diff --git a/.prettierrc b/.prettierrc
index ec986c7a..2caa9822 100644
--- a/.prettierrc
+++ b/.prettierrc
@@ -3,6 +3,7 @@
   "trailingComma": "es5",
   "semi": true,
   "singleQuote": true,
+  "tabWidth": 2,
   "overrides": [
     {
       "files": "*.sol",
diff --git a/contracts/configuration/LendingPoolAddressesProviderRegistry.sol b/contracts/configuration/LendingPoolAddressesProviderRegistry.sol
index 07d416f8..ee0caf16 100644
--- a/contracts/configuration/LendingPoolAddressesProviderRegistry.sol
+++ b/contracts/configuration/LendingPoolAddressesProviderRegistry.sol
@@ -5,6 +5,7 @@ import {Ownable} from '@openzeppelin/contracts/access/Ownable.sol';
 import {
   ILendingPoolAddressesProviderRegistry
 } from '../interfaces/ILendingPoolAddressesProviderRegistry.sol';
+import {Errors} from '../libraries/helpers/Errors.sol';
 
 /**
  * @title LendingPoolAddressesProviderRegistry contract
@@ -63,7 +64,7 @@ contract LendingPoolAddressesProviderRegistry is Ownable, ILendingPoolAddressesP
    * @param provider the pool address to be unregistered
    **/
   function unregisterAddressesProvider(address provider) external override onlyOwner {
-    require(addressesProviders[provider] > 0, 'Provider is not registered');
+    require(addressesProviders[provider] > 0, Errors.PROVIDER_NOT_REGISTERED);
     addressesProviders[provider] = 0;
     emit AddressesProviderUnregistered(provider);
   }
diff --git a/contracts/lendingpool/LendingPool.sol b/contracts/lendingpool/LendingPool.sol
index ec587920..e38ee13a 100644
--- a/contracts/lendingpool/LendingPool.sol
+++ b/contracts/lendingpool/LendingPool.sol
@@ -11,6 +11,7 @@ import {
 import {ILendingPoolAddressesProvider} from '../interfaces/ILendingPoolAddressesProvider.sol';
 import {IAToken} from '../tokenization/interfaces/IAToken.sol';
 import {Helpers} from '../libraries/helpers/Helpers.sol';
+import {Errors} from '../libraries/helpers/Errors.sol';
 import {WadRayMath} from '../libraries/math/WadRayMath.sol';
 import {ReserveLogic} from '../libraries/logic/ReserveLogic.sol';
 import {GenericLogic} from '../libraries/logic/GenericLogic.sol';
@@ -55,7 +56,10 @@ contract LendingPool is ReentrancyGuard, VersionedInitializable, ILendingPool {
    * @dev only lending pools configurator can use functions affected by this modifier
    **/
   modifier onlyLendingPoolConfigurator {
-    require(_addressesProvider.getLendingPoolConfigurator() == msg.sender, '30');
+    require(
+      _addressesProvider.getLendingPoolConfigurator() == msg.sender,
+      Errors.CALLER_NOT_LENDING_POOL_CONFIGURATOR
+    );
     _;
   }
 
@@ -344,7 +348,7 @@ contract LendingPool is ReentrancyGuard, VersionedInitializable, ILendingPool {
     uint256 stableBorrowBalance = IERC20(address(stableDebtToken)).balanceOf(user);
 
     // user must be borrowing on asset at a stable rate
-    require(stableBorrowBalance > 0, 'User does not have any stable rate loan for this reserve');
+    require(stableBorrowBalance > 0, Errors.NOT_ENOUGH_STABLE_BORROW_BALANCE);
 
     uint256 rebalanceDownRateThreshold = reserve.currentStableBorrowRate.rayMul(
       WadRayMath.ray().add(REBALANCE_DOWN_RATE_DELTA)
@@ -359,7 +363,7 @@ contract LendingPool is ReentrancyGuard, VersionedInitializable, ILendingPool {
 
     require(
       userStableRate < reserve.currentLiquidityRate || userStableRate > rebalanceDownRateThreshold,
-      'Interest rate rebalance conditions were not met'
+      Errors.INTEREST_RATE_REBALANCE_CONDITIONS_NOT_MET
     );
 
     //burn old debt tokens, mint new ones
@@ -435,7 +439,7 @@ contract LendingPool is ReentrancyGuard, VersionedInitializable, ILendingPool {
         receiveAToken
       )
     );
-    require(success, 'Liquidation call failed');
+    require(success, Errors.LIQUIDATION_CALL_FAILED);
 
     (uint256 returnCode, string memory returnMessage) = abi.decode(result, (uint256, string));
 
@@ -469,11 +473,8 @@ contract LendingPool is ReentrancyGuard, VersionedInitializable, ILendingPool {
     //calculate amount fee
     uint256 amountFee = amount.mul(FLASHLOAN_FEE_TOTAL).div(10000);
 
-    require(
-      availableLiquidityBefore >= amount,
-      'There is not enough liquidity available to borrow'
-    );
-    require(amountFee > 0, 'The requested amount is too small for a FlashLoan.');
+    require(availableLiquidityBefore >= amount, Errors.NOT_ENOUGH_LIQUIDITY_TO_BORROW);
+    require(amountFee > 0, Errors.REQUESTED_AMOUNT_TOO_SMALL);
 
     //get the FlashLoanReceiver instance
     IFlashLoanReceiver receiver = IFlashLoanReceiver(receiverAddress);
@@ -489,7 +490,7 @@ contract LendingPool is ReentrancyGuard, VersionedInitializable, ILendingPool {
 
     require(
       availableLiquidityAfter == availableLiquidityBefore.add(amountFee),
-      'The actual balance of the protocol is inconsistent'
+      Errors.INCONSISTENT_PROTOCOL_ACTUAL_BALANCE
     );
 
     //compounding the cumulated interest
diff --git a/contracts/lendingpool/LendingPoolConfigurator.sol b/contracts/lendingpool/LendingPoolConfigurator.sol
index 5a2d732b..e9c0a292 100644
--- a/contracts/lendingpool/LendingPoolConfigurator.sol
+++ b/contracts/lendingpool/LendingPoolConfigurator.sol
@@ -13,6 +13,7 @@ import {ReserveConfiguration} from '../libraries/configuration/ReserveConfigurat
 import {ILendingPoolAddressesProvider} from '../interfaces/ILendingPoolAddressesProvider.sol';
 import {ILendingPool} from '../interfaces/ILendingPool.sol';
 import {IERC20Detailed} from '../interfaces/IERC20Detailed.sol';
+import {Errors} from '../libraries/helpers/Errors.sol';
 
 /**
  * @title LendingPoolConfigurator contract
@@ -178,7 +179,7 @@ contract LendingPoolConfigurator is VersionedInitializable {
   modifier onlyLendingPoolManager {
     require(
       addressesProvider.getLendingPoolManager() == msg.sender,
-      'The caller must be a lending pool manager'
+      Errors.CALLER_NOT_LENDING_POOL_MANAGER
     );
     _;
   }
@@ -425,7 +426,7 @@ contract LendingPoolConfigurator is VersionedInitializable {
     ) = pool.getReserveData(asset);
     require(
       availableLiquidity == 0 && totalBorrowsStable == 0 && totalBorrowsVariable == 0,
-      'The liquidity of the reserve needs to be 0'
+      Errors.RESERVE_LIQUIDITY_NOT_0
     );
 
     ReserveConfiguration.Map memory currentConfig = pool.getConfiguration(asset);
diff --git a/contracts/lendingpool/LendingPoolLiquidationManager.sol b/contracts/lendingpool/LendingPoolLiquidationManager.sol
index a36ed3f3..34cb6f38 100644
--- a/contracts/lendingpool/LendingPoolLiquidationManager.sol
+++ b/contracts/lendingpool/LendingPoolLiquidationManager.sol
@@ -21,6 +21,7 @@ import {Helpers} from '../libraries/helpers/Helpers.sol';
 import {WadRayMath} from '../libraries/math/WadRayMath.sol';
 import {PercentageMath} from '../libraries/math/PercentageMath.sol';
 import {SafeERC20} from '@openzeppelin/contracts/token/ERC20/SafeERC20.sol';
+import {Errors} from '../libraries/helpers/Errors.sol';
 
 /**
  * @title LendingPoolLiquidationManager contract
@@ -132,7 +133,7 @@ contract LendingPoolLiquidationManager is ReentrancyGuard, VersionedInitializabl
     if (vars.healthFactor >= GenericLogic.HEALTH_FACTOR_LIQUIDATION_THRESHOLD) {
       return (
         uint256(LiquidationErrors.HEALTH_FACTOR_ABOVE_THRESHOLD),
-        'Health factor is not below the threshold'
+        Errors.HEALTH_FACTOR_NOT_BELOW_THRESHOLD
       );
     }
 
@@ -148,7 +149,7 @@ contract LendingPoolLiquidationManager is ReentrancyGuard, VersionedInitializabl
     if (!vars.isCollateralEnabled) {
       return (
         uint256(LiquidationErrors.COLLATERAL_CANNOT_BE_LIQUIDATED),
-        'The collateral chosen cannot be liquidated'
+        Errors.COLLATERAL_CANNOT_BE_LIQUIDATED
       );
     }
 
@@ -161,7 +162,7 @@ contract LendingPoolLiquidationManager is ReentrancyGuard, VersionedInitializabl
     if (vars.userStableDebt == 0 && vars.userVariableDebt == 0) {
       return (
         uint256(LiquidationErrors.CURRRENCY_NOT_BORROWED),
-        'User did not borrow the specified currency'
+        Errors.SPECIFIED_CURRENCY_NOT_BORROWED_BY_USER
       );
     }
 
@@ -202,7 +203,7 @@ contract LendingPoolLiquidationManager is ReentrancyGuard, VersionedInitializabl
       if (currentAvailableCollateral < vars.maxCollateralToLiquidate) {
         return (
           uint256(LiquidationErrors.NOT_ENOUGH_LIQUIDITY),
-          "There isn't enough liquidity available to liquidate"
+          Errors.NOT_ENOUGH_LIQUIDITY_TO_LIQUIDATE
         );
       }
     }
@@ -268,7 +269,7 @@ contract LendingPoolLiquidationManager is ReentrancyGuard, VersionedInitializabl
       receiveAToken
     );
 
-    return (uint256(LiquidationErrors.NO_ERROR), 'No errors');
+    return (uint256(LiquidationErrors.NO_ERROR), Errors.NO_ERRORS);
   }
 
   struct AvailableCollateralToLiquidateLocalVars {
diff --git a/contracts/libraries/helpers/Errors.sol b/contracts/libraries/helpers/Errors.sol
new file mode 100644
index 00000000..079d1b9f
--- /dev/null
+++ b/contracts/libraries/helpers/Errors.sol
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: agpl-3.0
+pragma solidity ^0.6.8;
+
+/**
+ * @title Errors library
+ * @author Aave
+ * @notice Implements error messages.
+ */
+library Errors {
+  // require error messages - ValidationLogic
+  string public constant AMOUNT_NOT_GREATER_THAN_0 = '1'; // 'Amount must be greater than 0'
+  string public constant NO_ACTIVE_RESERVE = '2'; // 'Action requires an active reserve'
+  string public constant NO_UNFREEZED_RESERVE = '3'; // 'Action requires an unfreezed reserve'
+  string public constant CURRENT_AVAILABLE_LIQUIDITY_NOT_ENOUGH = '4'; // 'The current liquidity is not enough'
+  string public constant NOT_ENOUGH_AVAILABLE_USER_BALANCE = '5'; // 'User cannot withdraw more than the available balance'
+  string public constant TRANSFER_NOT_ALLOWED = '6'; // 'Transfer cannot be allowed.'
+  string public constant BORROWING_NOT_ENABLED = '7'; // 'Borrowing is not enabled'
+  string public constant INVALID_INTEREST_RATE_MODE_SELECTED = '8'; // 'Invalid interest rate mode selected'
+  string public constant COLLATERAL_BALANCE_IS_0 = '9'; // 'The collateral balance is 0'
+  string public constant HEALTH_FACTOR_LOWER_THAN_LIQUIDATION_THRESHOLD = '10'; // 'Health factor is lesser than the liquidation threshold'
+  string public constant COLLATERAL_CANNOT_COVER_NEW_BORROW = '11'; // 'There is not enough collateral to cover a new borrow'
+  string public constant STABLE_BORROWING_NOT_ENABLED = '12'; // stable borrowing not enabled
+  string public constant CALLATERAL_SAME_AS_BORROWING_CURRENCY = '13'; // collateral is (mostly) the same currency that is being borrowed
+  string public constant AMOUNT_BIGGER_THAN_MAX_LOAN_SIZE_STABLE = '14'; // 'The requested amount is greater than the max loan size in stable rate mode
+  string public constant NO_DEBT_OF_SELECTED_TYPE = '15'; // 'for repayment of stable debt, the user needs to have stable debt, otherwise, he needs to have variable debt'
+  string public constant NO_EXPLICIT_AMOUNT_TO_REPAY_ON_BEHALF = '16'; // 'To repay on behalf of an user an explicit amount to repay is needed'
+  string public constant NO_STABLE_RATE_LOAN_IN_RESERVE = '17'; // 'User does not have a stable rate loan in progress on this reserve'
+  string public constant NO_VARIABLE_RATE_LOAN_IN_RESERVE = '18'; // 'User does not have a variable rate loan in progress on this reserve'
+  string public constant UNDERLYING_BALANCE_NOT_GREATER_THAN_0 = '19'; // 'The underlying balance needs to be greater than 0'
+  string public constant DEPOSIT_ALREADY_IN_USE = '20'; // 'User deposit is already being used as collateral'
+
+  // require error messages - LendingPool
+  string public constant NOT_ENOUGH_STABLE_BORROW_BALANCE = '21'; // 'User does not have any stable rate loan for this reserve'
+  string public constant INTEREST_RATE_REBALANCE_CONDITIONS_NOT_MET = '22'; // 'Interest rate rebalance conditions were not met'
+  string public constant LIQUIDATION_CALL_FAILED = '23'; // 'Liquidation call failed'
+  string public constant NOT_ENOUGH_LIQUIDITY_TO_BORROW = '24'; // 'There is not enough liquidity available to borrow'
+  string public constant REQUESTED_AMOUNT_TOO_SMALL = '25'; // 'The requested amount is too small for a FlashLoan.'
+  string public constant INCONSISTENT_PROTOCOL_ACTUAL_BALANCE = '26'; // 'The actual balance of the protocol is inconsistent'
+  string public constant CALLER_NOT_LENDING_POOL_CONFIGURATOR = '27'; // 'The actual balance of the protocol is inconsistent'
+
+  // require error messages - aToken
+  string public constant CALLER_MUST_BE_LENDING_POOL = '28'; // 'The caller of this function must be a lending pool'
+  string public constant INTEREST_REDIRECTION_NOT_ALLOWED = '29'; // 'Caller is not allowed to redirect the interest of the user'
+  string public constant CANNOT_GIVE_ALLOWANCE_TO_HIMSELF = '30'; // 'User cannot give allowance to himself'
+  string public constant TRANSFER_AMOUNT_NOT_GT_0 = '31'; // 'Transferred amount needs to be greater than zero'
+  string public constant INTEREST_ALREADY_REDIRECTED = '32'; // 'Interest is already redirected to the user'
+  string public constant NO_VALID_BALANCE_FOR_REDIRECTION = '33'; // 'Interest stream can only be redirected if there is a valid balance'
+
+  // require error messages - ReserveLogic
+  string public constant RESERVE_ALREADY_INITIALIZED = '34'; // 'Reserve has already been initialized'
+
+  //require error messages - LendingPoolConfiguration
+  string public constant CALLER_NOT_LENDING_POOL_MANAGER = '35'; // 'The caller must be a lending pool manager'
+  string public constant RESERVE_LIQUIDITY_NOT_0 = '36'; // 'The liquidity of the reserve needs to be 0'
+
+  //require error messages - LendingPoolAddressesProviderRegistry
+  string public constant PROVIDER_NOT_REGISTERED = '37'; // 'Provider is not registered'
+
+  //return error messages - LendingPoolLiquidationManager
+  string public constant HEALTH_FACTOR_NOT_BELOW_THRESHOLD = '38'; // 'Health factor is not below the threshold'
+  string public constant COLLATERAL_CANNOT_BE_LIQUIDATED = '39'; // 'The collateral chosen cannot be liquidated'
+  string public constant SPECIFIED_CURRENCY_NOT_BORROWED_BY_USER = '40'; // 'User did not borrow the specified currency'
+  string public constant NOT_ENOUGH_LIQUIDITY_TO_LIQUIDATE = '41'; // "There isn't enough liquidity available to liquidate"
+  string public constant NO_ERRORS = '42'; // 'No errors'
+}
diff --git a/contracts/libraries/logic/ReserveLogic.sol b/contracts/libraries/logic/ReserveLogic.sol
index 893ca5c5..c4871668 100644
--- a/contracts/libraries/logic/ReserveLogic.sol
+++ b/contracts/libraries/logic/ReserveLogic.sol
@@ -10,6 +10,7 @@ import {IStableDebtToken} from '../../tokenization/interfaces/IStableDebtToken.s
 import {ReserveConfiguration} from '../configuration/ReserveConfiguration.sol';
 import {IReserveInterestRateStrategy} from '../../interfaces/IReserveInterestRateStrategy.sol';
 import {WadRayMath} from '../math/WadRayMath.sol';
+import {Errors} from '../helpers/Errors.sol';
 
 /**
  * @title ReserveLogic library
@@ -180,7 +181,7 @@ library ReserveLogic {
     address variableDebtTokenAddress,
     address interestRateStrategyAddress
   ) external {
-    require(reserve.aTokenAddress == address(0), 'Reserve has already been initialized');
+    require(reserve.aTokenAddress == address(0), Errors.RESERVE_ALREADY_INITIALIZED);
     if (reserve.lastLiquidityIndex == 0) {
       //if the reserve has not been initialized yet
       reserve.lastLiquidityIndex = WadRayMath.ray();
diff --git a/contracts/libraries/logic/ValidationLogic.sol b/contracts/libraries/logic/ValidationLogic.sol
index abba4592..4541f489 100644
--- a/contracts/libraries/logic/ValidationLogic.sol
+++ b/contracts/libraries/logic/ValidationLogic.sol
@@ -12,6 +12,7 @@ import {SafeERC20} from '@openzeppelin/contracts/token/ERC20/SafeERC20.sol';
 import {ReserveConfiguration} from '../configuration/ReserveConfiguration.sol';
 import {UserConfiguration} from '../configuration/UserConfiguration.sol';
 import {IPriceOracleGetter} from '../../interfaces/IPriceOracleGetter.sol';
+import {Errors} from '../helpers/Errors.sol';
 
 /**
  * @title ReserveLogic library
@@ -32,15 +33,12 @@ library ValidationLogic {
    * @param reserve the reserve state on which the user is depositing
    * @param amount the amount to be deposited
    */
-  function validateDeposit(ReserveLogic.ReserveData storage reserve, uint256 amount)
-    internal
-    view
-  {
+  function validateDeposit(ReserveLogic.ReserveData storage reserve, uint256 amount) internal view {
     (bool isActive, bool isFreezed, , ) = reserve.configuration.getFlags();
 
-    require(amount > 0, 'Amount must be greater than 0');
-    require(isActive, 'Action requires an active reserve');
-    require(!isFreezed, 'Action requires an unfreezed reserve');
+    require(amount > 0, Errors.AMOUNT_NOT_GREATER_THAN_0);
+    require(isActive, Errors.NO_ACTIVE_RESERVE);
+    require(!isFreezed, Errors.NO_UNFREEZED_RESERVE);
   }
 
   /**
@@ -60,13 +58,13 @@ library ValidationLogic {
     address[] calldata reserves,
     address oracle
   ) external view {
-    require(amount > 0, 'Amount must be greater than 0');
+    require(amount > 0, Errors.AMOUNT_NOT_GREATER_THAN_0);
 
     uint256 currentAvailableLiquidity = IERC20(reserveAddress).balanceOf(address(aTokenAddress));
 
-    require(currentAvailableLiquidity >= amount, '4');
+    require(currentAvailableLiquidity >= amount, Errors.CURRENT_AVAILABLE_LIQUIDITY_NOT_ENOUGH);
 
-    require(amount <= userBalance, 'User cannot withdraw more than the available balance');
+    require(amount <= userBalance, Errors.NOT_ENOUGH_AVAILABLE_USER_BALANCE);
 
     require(
       GenericLogic.balanceDecreaseAllowed(
@@ -78,7 +76,7 @@ library ValidationLogic {
         reserves,
         oracle
       ),
-      'Transfer cannot be allowed.'
+      Errors.TRANSFER_NOT_ALLOWED
     );
   }
 
@@ -138,22 +136,22 @@ library ValidationLogic {
       vars.stableRateBorrowingEnabled
     ) = reserve.configuration.getFlags();
 
-    require(vars.isActive, 'Action requires an active reserve');
-    require(!vars.isFreezed, 'Action requires an unfreezed reserve');
+    require(vars.isActive, Errors.NO_ACTIVE_RESERVE);
+    require(!vars.isFreezed, Errors.NO_UNFREEZED_RESERVE);
 
-    require(vars.borrowingEnabled, '5');
+    require(vars.borrowingEnabled, Errors.BORROWING_NOT_ENABLED);
 
     //validate interest rate mode
     require(
       uint256(ReserveLogic.InterestRateMode.VARIABLE) == interestRateMode ||
         uint256(ReserveLogic.InterestRateMode.STABLE) == interestRateMode,
-      'Invalid interest rate mode selected'
+      Errors.INVALID_INTEREST_RATE_MODE_SELECTED
     );
 
     //check that the amount is available in the reserve
     vars.availableLiquidity = IERC20(reserveAddress).balanceOf(address(reserve.aTokenAddress));
 
-    require(vars.availableLiquidity >= amount, '7');
+    require(vars.availableLiquidity >= amount, Errors.CURRENT_AVAILABLE_LIQUIDITY_NOT_ENOUGH);
 
     (
       vars.userCollateralBalanceETH,
@@ -169,9 +167,12 @@ library ValidationLogic {
       oracle
     );
 
-    require(vars.userCollateralBalanceETH > 0, 'The collateral balance is 0');
+    require(vars.userCollateralBalanceETH > 0, Errors.COLLATERAL_BALANCE_IS_0);
 
-    require(vars.healthFactor > GenericLogic.HEALTH_FACTOR_LIQUIDATION_THRESHOLD, '8');
+    require(
+      vars.healthFactor > GenericLogic.HEALTH_FACTOR_LIQUIDATION_THRESHOLD,
+      Errors.HEALTH_FACTOR_LOWER_THAN_LIQUIDATION_THRESHOLD
+    );
 
     //add the current already borrowed amount to the amount requested to calculate the total collateral needed.
     vars.amountOfCollateralNeededETH = vars.userBorrowBalanceETH.add(amountInETH).percentDiv(
@@ -180,7 +181,7 @@ library ValidationLogic {
 
     require(
       vars.amountOfCollateralNeededETH <= vars.userCollateralBalanceETH,
-      'There is not enough collateral to cover a new borrow'
+      Errors.COLLATERAL_CANNOT_COVER_NEW_BORROW
     );
 
     /**
@@ -195,20 +196,20 @@ library ValidationLogic {
     if (vars.rateMode == ReserveLogic.InterestRateMode.STABLE) {
       //check if the borrow mode is stable and if stable rate borrowing is enabled on this reserve
 
-      require(vars.stableRateBorrowingEnabled, '11');
+      require(vars.stableRateBorrowingEnabled, Errors.STABLE_BORROWING_NOT_ENABLED);
 
       require(
         !userConfig.isUsingAsCollateral(reserve.index) ||
           reserve.configuration.getLtv() == 0 ||
           amount > IERC20(reserve.aTokenAddress).balanceOf(msg.sender),
-        '12'
+        Errors.CALLATERAL_SAME_AS_BORROWING_CURRENCY
       );
 
       //calculate the max available loan size in stable rate mode as a percentage of the
       //available liquidity
       uint256 maxLoanSizeStable = vars.availableLiquidity.percentMul(maxStableLoanPercent);
 
-      require(amount <= maxLoanSizeStable, '13');
+      require(amount <= maxLoanSizeStable, Errors.AMOUNT_BIGGER_THAN_MAX_LOAN_SIZE_STABLE);
     }
   }
 
@@ -230,21 +231,21 @@ library ValidationLogic {
   ) external view {
     bool isActive = reserve.configuration.getActive();
 
-    require(isActive, 'Action requires an active reserve');
+    require(isActive, Errors.NO_ACTIVE_RESERVE);
 
-    require(amountSent > 0, 'Amount must be greater than 0');
+    require(amountSent > 0, Errors.AMOUNT_NOT_GREATER_THAN_0);
 
     require(
       (stableDebt > 0 &&
         ReserveLogic.InterestRateMode(rateMode) == ReserveLogic.InterestRateMode.STABLE) ||
         (variableDebt > 0 &&
           ReserveLogic.InterestRateMode(rateMode) == ReserveLogic.InterestRateMode.VARIABLE),
-      '16'
+      Errors.NO_DEBT_OF_SELECTED_TYPE
     );
 
     require(
       amountSent != uint256(-1) || msg.sender == onBehalfOf,
-      'To repay on behalf of an user an explicit amount to repay is needed'
+      Errors.NO_EXPLICIT_AMOUNT_TO_REPAY_ON_BEHALF
     );
   }
 
@@ -265,19 +266,13 @@ library ValidationLogic {
   ) external view {
     (bool isActive, bool isFreezed, , bool stableRateEnabled) = reserve.configuration.getFlags();
 
-    require(isActive, 'Action requires an active reserve');
-    require(!isFreezed, 'Action requires an unfreezed reserve');
+    require(isActive, Errors.NO_ACTIVE_RESERVE);
+    require(!isFreezed, Errors.NO_UNFREEZED_RESERVE);
 
     if (currentRateMode == ReserveLogic.InterestRateMode.STABLE) {
-      require(
-        stableBorrowBalance > 0,
-        'User does not have a stable rate loan in progress on this reserve'
-      );
+      require(stableBorrowBalance > 0, Errors.NO_STABLE_RATE_LOAN_IN_RESERVE);
     } else if (currentRateMode == ReserveLogic.InterestRateMode.VARIABLE) {
-      require(
-        variableBorrowBalance > 0,
-        'User does not have a variable rate loan in progress on this reserve'
-      );
+      require(variableBorrowBalance > 0, Errors.NO_VARIABLE_RATE_LOAN_IN_RESERVE);
       /**
        * user wants to swap to stable, before swapping we need to ensure that
        * 1. stable borrow rate is enabled on the reserve
@@ -285,17 +280,17 @@ library ValidationLogic {
        * more collateral than he is borrowing, artificially lowering
        * the interest rate, borrowing at variable, and switching to stable
        **/
-      require(stableRateEnabled, '11');
+      require(stableRateEnabled, Errors.STABLE_BORROWING_NOT_ENABLED);
 
       require(
         !userConfig.isUsingAsCollateral(reserve.index) ||
           reserve.configuration.getLtv() == 0 ||
           stableBorrowBalance.add(variableBorrowBalance) >
           IERC20(reserve.aTokenAddress).balanceOf(msg.sender),
-        '12'
+        Errors.CALLATERAL_SAME_AS_BORROWING_CURRENCY
       );
     } else {
-      revert('Invalid interest rate mode selected');
+      revert(Errors.INVALID_INTEREST_RATE_MODE_SELECTED);
     }
   }
 
@@ -318,7 +313,7 @@ library ValidationLogic {
   ) external view {
     uint256 underlyingBalance = IERC20(reserve.aTokenAddress).balanceOf(msg.sender);
 
-    require(underlyingBalance > 0, '22');
+    require(underlyingBalance > 0, Errors.UNDERLYING_BALANCE_NOT_GREATER_THAN_0);
 
     require(
       GenericLogic.balanceDecreaseAllowed(
@@ -330,7 +325,7 @@ library ValidationLogic {
         reserves,
         oracle
       ),
-      'User deposit is already being used as collateral'
+      Errors.DEPOSIT_ALREADY_IN_USE
     );
   }
 }
diff --git a/contracts/tokenization/AToken.sol b/contracts/tokenization/AToken.sol
index 0deb6dc2..3ec3eac5 100644
--- a/contracts/tokenization/AToken.sol
+++ b/contracts/tokenization/AToken.sol
@@ -4,6 +4,7 @@ pragma solidity ^0.6.8;
 import {ERC20} from './ERC20.sol';
 import {LendingPool} from '../lendingpool/LendingPool.sol';
 import {WadRayMath} from '../libraries/math/WadRayMath.sol';
+import {Errors} from '../libraries/helpers/Errors.sol';
 import {SafeERC20} from '@openzeppelin/contracts/token/ERC20/SafeERC20.sol';
 import {
   VersionedInitializable
@@ -34,12 +35,12 @@ contract AToken is VersionedInitializable, ERC20, IAToken {
   uint256 public constant ATOKEN_REVISION = 0x1;
 
   modifier onlyLendingPool {
-    require(msg.sender == address(_pool), 'The caller of this function must be a lending pool');
+    require(msg.sender == address(_pool), Errors.CALLER_MUST_BE_LENDING_POOL);
     _;
   }
 
   modifier whenTransferAllowed(address from, uint256 amount) {
-    require(isTransferAllowed(from, amount), 'Transfer cannot be allowed.');
+    require(isTransferAllowed(from, amount), Errors.TRANSFER_NOT_ALLOWED);
     _;
   }
 
@@ -100,7 +101,7 @@ contract AToken is VersionedInitializable, ERC20, IAToken {
   function redirectInterestStreamOf(address from, address to) external override {
     require(
       msg.sender == _interestRedirectionAllowances[from],
-      'Caller is not allowed to redirect the interest of the user'
+      Errors.INTEREST_REDIRECTION_NOT_ALLOWED
     );
     _redirectInterestStream(from, to);
   }
@@ -112,7 +113,7 @@ contract AToken is VersionedInitializable, ERC20, IAToken {
    * the allowance.
    **/
   function allowInterestRedirectionTo(address to) external override {
-    require(to != msg.sender, 'User cannot give allowance to himself');
+    require(to != msg.sender, Errors.CANNOT_GIVE_ALLOWANCE_TO_HIMSELF);
     _interestRedirectionAllowances[msg.sender] = to;
     emit InterestRedirectionAllowanceChanged(msg.sender, to);
   }
@@ -434,15 +435,12 @@ contract AToken is VersionedInitializable, ERC20, IAToken {
     address to,
     uint256 value
   ) internal {
-    require(value > 0, 'Transferred amount needs to be greater than zero');
+    require(value > 0, Errors.TRANSFER_AMOUNT_NOT_GT_0);
 
     //cumulate the balance of the sender
-    (
-      ,
-      uint256 fromBalance,
-      uint256 fromBalanceIncrease,
-      uint256 fromIndex
-    ) = _cumulateBalance(from);
+    (, uint256 fromBalance, uint256 fromBalanceIncrease, uint256 fromIndex) = _cumulateBalance(
+      from
+    );
 
     //cumulate the balance of the receiver
     (, , uint256 toBalanceIncrease, uint256 toIndex) = _cumulateBalance(to);
@@ -486,7 +484,7 @@ contract AToken is VersionedInitializable, ERC20, IAToken {
   function _redirectInterestStream(address from, address to) internal {
     address currentRedirectionAddress = _interestRedirectionAddresses[from];
 
-    require(to != currentRedirectionAddress, 'Interest is already redirected to the user');
+    require(to != currentRedirectionAddress, Errors.INTEREST_ALREADY_REDIRECTED);
 
     //accumulates the accrued interest to the principal
     (
@@ -496,7 +494,7 @@ contract AToken is VersionedInitializable, ERC20, IAToken {
       uint256 fromIndex
     ) = _cumulateBalance(from);
 
-    require(fromBalance > 0, 'Interest stream can only be redirected if there is a valid balance');
+    require(fromBalance > 0, Errors.NO_VALID_BALANCE_FOR_REDIRECTION);
 
     //if the user is already redirecting the interest to someone, before changing
     //the redirection address we substract the redirected balance of the previous
diff --git a/contracts/tokenization/base/DebtTokenBase.sol b/contracts/tokenization/base/DebtTokenBase.sol
index 87b83e0e..33d7222d 100644
--- a/contracts/tokenization/base/DebtTokenBase.sol
+++ b/contracts/tokenization/base/DebtTokenBase.sol
@@ -9,6 +9,7 @@ import {
   VersionedInitializable
 } from '../../libraries/openzeppelin-upgradeability/VersionedInitializable.sol';
 import {IERC20Detailed} from '../../interfaces/IERC20Detailed.sol';
+import {Errors} from '../../libraries/helpers/Errors.sol';
 
 /**
  * @title contract DebtTokenBase
@@ -33,7 +34,7 @@ abstract contract DebtTokenBase is IERC20Detailed, VersionedInitializable {
    * @dev only lending pool can call functions marked by this modifier
    **/
   modifier onlyLendingPool {
-    require(msg.sender == address(_pool), 'The caller of this function must be a lending pool');
+    require(msg.sender == address(_pool), Errors.CALLER_MUST_BE_LENDING_POOL);
     _;
   }
 
diff --git a/helpers/types.ts b/helpers/types.ts
index 106e5376..f17d5e9f 100644
--- a/helpers/types.ts
+++ b/helpers/types.ts
@@ -44,25 +44,71 @@ export enum eContractid {
 }
 
 export enum ProtocolErrors {
-  INVALID_CONFIGURATOR_CALLER_MSG = 'The caller must be a lending pool configurator contract',
-  INVALID_POOL_CALLER_MSG = 'The caller must be a lending pool contract',
-  INVALID_POOL_CALLER_MSG_1 = 'The caller of this function must be a lending pool',
-  INVALID_POOL_MANAGER_CALLER_MSG = 'The caller must be a lending pool manager',
+  // require error messages - ValidationLogic
+  AMOUNT_NOT_GREATER_THAN_0 = '1', // 'Amount must be greater than 0'
+  NO_ACTIVE_RESERVE = '2', // 'Action requires an active reserve'
+  NO_UNFREEZED_RESERVE = '3', // 'Action requires an unfreezed reserve'
+  CURRENT_AVAILABLE_LIQUIDITY_NOT_ENOUGH = '4', // 'The current liquidity is not enough'
+  NOT_ENOUGH_AVAILABLE_USER_BALANCE = '5', // 'User cannot withdraw more than the available balance'
+  TRANSFER_NOT_ALLOWED = '6', // 'Transfer cannot be allowed.'
+  BORROWING_NOT_ENABLED = '7', // 'Borrowing is not enabled'
+  INVALID_INTEREST_RATE_MODE_SELECTED = '8', // 'Invalid interest rate mode selected'
+  COLLATERAL_BALANCE_IS_0 = '9', // 'The collateral balance is 0'
+  HEALTH_FACTOR_LOWER_THAN_LIQUIDATION_THRESHOLD = '10', // 'Health factor is lesser than the liquidation threshold'
+  COLLATERAL_CANNOT_COVER_NEW_BORROW = '11', // 'There is not enough collateral to cover a new borrow'
+  STABLE_BORROWING_NOT_ENABLED = '12', // stable borrowing not enabled
+  CALLATERAL_SAME_AS_BORROWING_CURRENCY = '13', // collateral is (mostly) the same currency that is being borrowed
+  AMOUNT_BIGGER_THAN_MAX_LOAN_SIZE_STABLE = '14', // 'The requested amount is greater than the max loan size in stable rate mode
+  NO_DEBT_OF_SELECTED_TYPE = '15', // 'for repayment of stable debt, the user needs to have stable debt, otherwise, he needs to have variable debt'
+  NO_EXPLICIT_AMOUNT_TO_REPAY_ON_BEHALF = '16', // 'To repay on behalf of an user an explicit amount to repay is needed'
+  NO_STABLE_RATE_LOAN_IN_RESERVE = '17', // 'User does not have a stable rate loan in progress on this reserve'
+  NO_VARIABLE_RATE_LOAN_IN_RESERVE = '18', // 'User does not have a variable rate loan in progress on this reserve'
+  UNDERLYING_BALANCE_NOT_GREATER_THAN_0 = '19', // 'The underlying balance needs to be greater than 0'
+  DEPOSIT_ALREADY_IN_USE = '20', // 'User deposit is already being used as collateral'
+
+  // require error messages - LendingPool
+  NOT_ENOUGH_STABLE_BORROW_BALANCE = '21', // 'User does not have any stable rate loan for this reserve'
+  INTEREST_RATE_REBALANCE_CONDITIONS_NOT_MET = '22', // 'Interest rate rebalance conditions were not met'
+  LIQUIDATION_CALL_FAILED = '23', // 'Liquidation call failed'
+  NOT_ENOUGH_LIQUIDITY_TO_BORROW = '24', // 'There is not enough liquidity available to borrow'
+  REQUESTED_AMOUNT_TOO_SMALL = '25', // 'The requested amount is too small for a FlashLoan.'
+  INCONSISTENT_PROTOCOL_ACTUAL_BALANCE = '26', // 'The actual balance of the protocol is inconsistent'
+  CALLER_NOT_LENDING_POOL_CONFIGURATOR = '27', // 'The actual balance of the protocol is inconsistent'
+
+  // require error messages - aToken
+  CALLER_MUST_BE_LENDING_POOL = '28', // 'The caller of this function must be a lending pool'
+  INTEREST_REDIRECTION_NOT_ALLOWED = '29', // 'Caller is not allowed to redirect the interest of the user'
+  CANNOT_GIVE_ALLOWANCE_TO_HIMSELF = '30', // 'User cannot give allowance to himself'
+  TRANSFER_AMOUNT_NOT_GT_0 = '31', // 'Transferred amount needs to be greater than zero'
+  INTEREST_ALREADY_REDIRECTED = '32', // 'Interest is already redirected to the user'
+  NO_VALID_BALANCE_FOR_REDIRECTION = '33', // 'Interest stream can only be redirected if there is a valid balance'
+
+  // require error messages - ReserveLogic
+  RESERVE_ALREADY_INITIALIZED = '34', // 'Reserve has already been initialized'
+
+  //require error messages - LendingPoolConfiguration
+  CALLER_NOT_LENDING_POOL_MANAGER = '35', // 'The caller must be a lending pool manager'
+  RESERVE_LIQUIDITY_NOT_0 = '36', // 'The liquidity of the reserve needs to be 0'
+
+  //require error messages - LendingPoolAddressesProviderRegistry
+  PROVIDER_NOT_REGISTERED = '37', // 'Provider is not registered'
+
+  //return error messages - LendingPoolLiquidationManager
+  HEALTH_FACTOR_NOT_BELOW_THRESHOLD = '38', // 'Health factor is not below the threshold'
+  COLLATERAL_CANNOT_BE_LIQUIDATED = '39', // 'The collateral chosen cannot be liquidated'
+  SPECIFIED_CURRENCY_NOT_BORROWED_BY_USER = '40', // 'User did not borrow the specified currency'
+  NOT_ENOUGH_LIQUIDITY_TO_LIQUIDATE = '41', // "There isn't enough liquidity available to liquidate"
+  NO_ERRORS = '42', // 'No errors'
+
+  // old
+
   INVALID_FROM_BALANCE_AFTER_TRANSFER = 'Invalid from balance after transfer',
   INVALID_TO_BALANCE_AFTER_TRANSFER = 'Invalid from balance after transfer',
   INVALID_OWNER_REVERT_MSG = 'Ownable: caller is not the owner',
   INVALID_REDIRECTED_BALANCE_BEFORE_TRANSFER = 'Invalid redirected balance before transfer',
   INVALID_REDIRECTED_BALANCE_AFTER_TRANSFER = 'Invalid redirected balance after transfer',
   INVALID_REDIRECTION_ADDRESS = 'Invalid redirection address',
-  TRANSFERRED_AMOUNT_GT_ZERO = 'Transferred amount needs to be greater than zero',
-  ZERO_COLLATERAL = 'The collateral balance is 0',
-  INCONSISTENT_PROTOCOL_BALANCE = 'The actual balance of the protocol is inconsistent',
-  TOO_SMALL_FLASH_LOAN = 'The requested amount is too small for a FlashLoan.',
-  NOT_ENOUGH_LIQUIDITY_TO_BORROW = 'There is not enough liquidity available to borrow',
-  HF_IS_NOT_BELLOW_THRESHOLD = 'Health factor is not below the threshold',
   INVALID_HF = 'Invalid health factor',
-  USER_DID_NOT_BORROW_SPECIFIED = 'User did not borrow the specified currency',
-  THE_COLLATERAL_CHOSEN_CANNOT_BE_LIQUIDATED = 'The collateral chosen cannot be liquidated',
 }
 
 export type tEthereumAddress = string;
diff --git a/test/atoken-modifiers.spec.ts b/test/atoken-modifiers.spec.ts
index 97115c0c..406d910a 100644
--- a/test/atoken-modifiers.spec.ts
+++ b/test/atoken-modifiers.spec.ts
@@ -3,17 +3,17 @@ import {makeSuite, TestEnv} from './helpers/make-suite';
 import {ProtocolErrors} from '../helpers/types';
 
 makeSuite('AToken: Modifiers', (testEnv: TestEnv) => {
-  const {INVALID_POOL_CALLER_MSG_1} = ProtocolErrors;
+  const {CALLER_MUST_BE_LENDING_POOL} = ProtocolErrors;
 
   it('Tries to invoke mint not being the LendingPool', async () => {
     const {deployer, aDai} = testEnv;
-    await expect(aDai.mint(deployer.address, '1')).to.be.revertedWith(INVALID_POOL_CALLER_MSG_1);
+    await expect(aDai.mint(deployer.address, '1')).to.be.revertedWith(CALLER_MUST_BE_LENDING_POOL);
   });
 
   it('Tries to invoke burn not being the LendingPool', async () => {
     const {deployer, aDai} = testEnv;
     await expect(aDai.burn(deployer.address, deployer.address, '1')).to.be.revertedWith(
-      INVALID_POOL_CALLER_MSG_1
+      CALLER_MUST_BE_LENDING_POOL
     );
   });
 
@@ -21,13 +21,13 @@ makeSuite('AToken: Modifiers', (testEnv: TestEnv) => {
     const {deployer, users, aDai} = testEnv;
     await expect(
       aDai.transferOnLiquidation(deployer.address, users[0].address, '1')
-    ).to.be.revertedWith(INVALID_POOL_CALLER_MSG_1);
+    ).to.be.revertedWith(CALLER_MUST_BE_LENDING_POOL);
   });
 
   it('Tries to invoke transferUnderlyingTo not being the LendingPool', async () => {
     const {deployer, users, aDai} = testEnv;
     await expect(aDai.transferUnderlyingTo(deployer.address, '1')).to.be.revertedWith(
-      INVALID_POOL_CALLER_MSG_1
+      CALLER_MUST_BE_LENDING_POOL
     );
   });
 });
diff --git a/test/atoken-transfer.spec.ts b/test/atoken-transfer.spec.ts
index 138eda61..1c161608 100644
--- a/test/atoken-transfer.spec.ts
+++ b/test/atoken-transfer.spec.ts
@@ -17,8 +17,10 @@ makeSuite('AToken: Transfer', (testEnv: TestEnv) => {
     INVALID_REDIRECTED_BALANCE_BEFORE_TRANSFER,
     INVALID_REDIRECTED_BALANCE_AFTER_TRANSFER,
     INVALID_REDIRECTION_ADDRESS,
-    ZERO_COLLATERAL,
-    TRANSFERRED_AMOUNT_GT_ZERO,
+    // ZERO_COLLATERAL,
+    TRANSFER_AMOUNT_NOT_GT_0,
+    COLLATERAL_BALANCE_IS_0,
+    TRANSFER_NOT_ALLOWED,
   } = ProtocolErrors;
 
   it('User 0 deposits 1000 DAI, transfers to user 1', async () => {
@@ -96,16 +98,14 @@ makeSuite('AToken: Transfer', (testEnv: TestEnv) => {
     await weth.connect(users[0].signer).mint(await convertToCurrencyDecimals(weth.address, '1'));
 
     await weth.connect(users[0].signer).approve(pool.address, APPROVAL_AMOUNT_LENDING_POOL);
-    
-    await pool
-      .connect(users[0].signer)
-      .deposit(weth.address, ethers.utils.parseEther('1.0'), '0');
+
+    await pool.connect(users[0].signer).deposit(weth.address, ethers.utils.parseEther('1.0'), '0');
     await expect(
       pool
         .connect(users[1].signer)
         .borrow(weth.address, ethers.utils.parseEther('0.1'), RateMode.Stable, AAVE_REFERRAL),
-      ZERO_COLLATERAL
-    ).to.be.revertedWith(ZERO_COLLATERAL);
+      COLLATERAL_BALANCE_IS_0
+    ).to.be.revertedWith(COLLATERAL_BALANCE_IS_0);
   });
 
   it('User 1 sets the DAI as collateral and borrows, tries to transfer everything back to user 0 (revert expected)', async () => {
@@ -120,25 +120,25 @@ makeSuite('AToken: Transfer', (testEnv: TestEnv) => {
 
     await expect(
       aDai.connect(users[1].signer).transfer(users[0].address, aDAItoTransfer),
-      'Transfer cannot be allowed.'
-    ).to.be.revertedWith('Transfer cannot be allowed.');
+      TRANSFER_NOT_ALLOWED
+    ).to.be.revertedWith(TRANSFER_NOT_ALLOWED);
   });
 
   it('User 0 tries to transfer 0 balance (revert expected)', async () => {
     const {users, pool, aDai, dai, weth} = testEnv;
     await expect(
       aDai.connect(users[0].signer).transfer(users[1].address, '0'),
-      TRANSFERRED_AMOUNT_GT_ZERO
-    ).to.be.revertedWith(TRANSFERRED_AMOUNT_GT_ZERO);
+      TRANSFER_AMOUNT_NOT_GT_0
+    ).to.be.revertedWith(TRANSFER_AMOUNT_NOT_GT_0);
   });
 
   it('User 1 repays the borrow, transfers aDAI back to user 0', async () => {
     const {users, pool, aDai, dai, weth} = testEnv;
- 
+
     await weth.connect(users[1].signer).mint(await convertToCurrencyDecimals(weth.address, '2'));
 
     await weth.connect(users[1].signer).approve(pool.address, APPROVAL_AMOUNT_LENDING_POOL);
- 
+
     await pool
       .connect(users[1].signer)
       .repay(weth.address, MAX_UINT_AMOUNT, RateMode.Stable, users[1].address);
diff --git a/test/configurator.spec.ts b/test/configurator.spec.ts
index 182f2f2b..a6513e54 100644
--- a/test/configurator.spec.ts
+++ b/test/configurator.spec.ts
@@ -6,7 +6,7 @@ import {ProtocolErrors} from '../helpers/types';
 const {expect} = require('chai');
 
 makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
-  const {INVALID_POOL_MANAGER_CALLER_MSG} = ProtocolErrors;
+  const {CALLER_NOT_LENDING_POOL_MANAGER, RESERVE_LIQUIDITY_NOT_0} = ProtocolErrors;
 
   it('Deactivates the ETH reserve', async () => {
     const {configurator, pool, weth} = testEnv;
@@ -27,16 +27,16 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).deactivateReserve(weth.address),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Check the onlyLendingPoolManager on activateReserve ', async () => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).activateReserve(weth.address),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Freezes the ETH reserve', async () => {
@@ -58,16 +58,16 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).freezeReserve(weth.address),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Check the onlyLendingPoolManager on unfreezeReserve ', async () => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).unfreezeReserve(weth.address),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Deactivates the ETH reserve for borrowing', async () => {
@@ -90,16 +90,16 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).disableBorrowingOnReserve(weth.address),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Check the onlyLendingPoolManager on enableBorrowingOnReserve ', async () => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).enableBorrowingOnReserve(weth.address, true),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Deactivates the ETH reserve as collateral', async () => {
@@ -121,8 +121,8 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).disableReserveAsCollateral(weth.address),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Check the onlyLendingPoolManager on enableReserveAsCollateral ', async () => {
@@ -131,8 +131,8 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
       configurator
         .connect(users[2].signer)
         .enableReserveAsCollateral(weth.address, '75', '80', '105'),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Disable stable borrow rate on the ETH reserve', async () => {
@@ -153,16 +153,16 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).disableReserveStableRate(weth.address),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Check the onlyLendingPoolManager on enableReserveStableRate', async () => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).enableReserveStableRate(weth.address),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Changes LTV of the reserve', async () => {
@@ -176,8 +176,8 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).setLtv(weth.address, '75'),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Changes liquidation threshold of the reserve', async () => {
@@ -194,8 +194,8 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).setLiquidationThreshold(weth.address, '80'),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Changes liquidation bonus of the reserve', async () => {
@@ -212,24 +212,24 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).setLiquidationBonus(weth.address, '80'),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Check the onlyLendingPoolManager on setReserveDecimals', async () => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).setReserveDecimals(weth.address, '80'),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Check the onlyLendingPoolManager on setLiquidationBonus', async () => {
     const {configurator, users, weth} = testEnv;
     await expect(
       configurator.connect(users[2].signer).setLiquidationBonus(weth.address, '80'),
-      INVALID_POOL_MANAGER_CALLER_MSG
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      CALLER_NOT_LENDING_POOL_MANAGER
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Reverts when trying to disable the DAI reserve with liquidity on it', async () => {
@@ -246,7 +246,7 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
 
     await expect(
       configurator.deactivateReserve(dai.address),
-      'The liquidity of the reserve needs to be 0'
-    ).to.be.revertedWith('The liquidity of the reserve needs to be 0');
+      RESERVE_LIQUIDITY_NOT_0
+    ).to.be.revertedWith(RESERVE_LIQUIDITY_NOT_0);
   });
 });
diff --git a/test/flashloan.spec.ts b/test/flashloan.spec.ts
index fcda8c28..223ea890 100644
--- a/test/flashloan.spec.ts
+++ b/test/flashloan.spec.ts
@@ -11,8 +11,8 @@ const {expect} = require('chai');
 makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
   let _mockFlashLoanReceiver = {} as MockFlashLoanReceiver;
   const {
-    INCONSISTENT_PROTOCOL_BALANCE,
-    TOO_SMALL_FLASH_LOAN,
+    INCONSISTENT_PROTOCOL_ACTUAL_BALANCE,
+    REQUESTED_AMOUNT_TOO_SMALL,
     NOT_ENOUGH_LIQUIDITY_TO_BORROW,
   } = ProtocolErrors;
 
@@ -62,7 +62,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
 
     const reserveDataBefore = await pool.getReserveData(weth.address);
 
-    console.log("Total liquidity is ", reserveDataBefore.availableLiquidity.toString());
+    console.log('Total liquidity is ', reserveDataBefore.availableLiquidity.toString());
 
     const txResult = await pool.flashLoan(
       _mockFlashLoanReceiver.address,
@@ -99,7 +99,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
         ethers.utils.parseEther('0.8'),
         '0x10'
       )
-    ).to.be.revertedWith(INCONSISTENT_PROTOCOL_BALANCE);
+    ).to.be.revertedWith(INCONSISTENT_PROTOCOL_ACTUAL_BALANCE);
   });
 
   it('tries to take a very small flashloan, which would result in 0 fees (revert expected)', async () => {
@@ -112,7 +112,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
         '1', //1 wei loan
         '0x10'
       )
-    ).to.be.revertedWith(TOO_SMALL_FLASH_LOAN);
+    ).to.be.revertedWith(REQUESTED_AMOUNT_TOO_SMALL);
   });
 
   it('tries to take a flashloan that is bigger than the available liquidity (revert expected)', async () => {
@@ -194,7 +194,7 @@ makeSuite('LendingPool FlashLoan function', (testEnv: TestEnv) => {
         ethers.utils.parseEther('500'),
         '0x10'
       ),
-      INCONSISTENT_PROTOCOL_BALANCE
-    ).to.be.revertedWith(INCONSISTENT_PROTOCOL_BALANCE);
+      INCONSISTENT_PROTOCOL_ACTUAL_BALANCE
+    ).to.be.revertedWith(INCONSISTENT_PROTOCOL_ACTUAL_BALANCE);
   });
 });
diff --git a/test/liquidation-atoken.spec.ts b/test/liquidation-atoken.spec.ts
index 6e4af1e1..921114f0 100644
--- a/test/liquidation-atoken.spec.ts
+++ b/test/liquidation-atoken.spec.ts
@@ -13,10 +13,10 @@ const {expect} = chai;
 
 makeSuite('LendingPool liquidation - liquidator receiving aToken', (testEnv) => {
   const {
-    HF_IS_NOT_BELLOW_THRESHOLD,
+    HEALTH_FACTOR_NOT_BELOW_THRESHOLD,
     INVALID_HF,
-    USER_DID_NOT_BORROW_SPECIFIED,
-    THE_COLLATERAL_CHOSEN_CANNOT_BE_LIQUIDATED,
+    SPECIFIED_CURRENCY_NOT_BORROWED_BY_USER,
+    COLLATERAL_CANNOT_BE_LIQUIDATED,
   } = ProtocolErrors;
 
   it('LIQUIDATION - Deposits WETH, borrows DAI/Check liquidation fails because health factor is above 1', async () => {
@@ -71,7 +71,7 @@ makeSuite('LendingPool liquidation - liquidator receiving aToken', (testEnv) =>
     //someone tries to liquidate user 2
     await expect(
       pool.liquidationCall(weth.address, dai.address, borrower.address, 1, true)
-    ).to.be.revertedWith(HF_IS_NOT_BELLOW_THRESHOLD);
+    ).to.be.revertedWith(HEALTH_FACTOR_NOT_BELOW_THRESHOLD);
   });
 
   it('LIQUIDATION - Drop the health factor below 1', async () => {
@@ -96,7 +96,7 @@ makeSuite('LendingPool liquidation - liquidator receiving aToken', (testEnv) =>
     //user 2 tries to borrow
     await expect(
       pool.liquidationCall(weth.address, weth.address, borrower.address, oneEther.toString(), true)
-    ).revertedWith(USER_DID_NOT_BORROW_SPECIFIED);
+    ).revertedWith(SPECIFIED_CURRENCY_NOT_BORROWED_BY_USER);
   });
 
   it('LIQUIDATION - Tries to liquidate a different collateral than the borrower collateral', async () => {
@@ -105,7 +105,7 @@ makeSuite('LendingPool liquidation - liquidator receiving aToken', (testEnv) =>
 
     await expect(
       pool.liquidationCall(dai.address, dai.address, borrower.address, oneEther.toString(), true)
-    ).revertedWith(THE_COLLATERAL_CHOSEN_CANNOT_BE_LIQUIDATED);
+    ).revertedWith(COLLATERAL_CANNOT_BE_LIQUIDATED);
   });
 
   it('LIQUIDATION - Liquidates the borrow', async () => {
diff --git a/test/liquidation-underlying.spec.ts b/test/liquidation-underlying.spec.ts
index 676c9c26..064e3856 100644
--- a/test/liquidation-underlying.spec.ts
+++ b/test/liquidation-underlying.spec.ts
@@ -13,12 +13,7 @@ const chai = require('chai');
 const {expect} = chai;
 
 makeSuite('LendingPool liquidation - liquidator receiving the underlying asset', (testEnv) => {
-  const {
-    HF_IS_NOT_BELLOW_THRESHOLD,
-    INVALID_HF,
-    USER_DID_NOT_BORROW_SPECIFIED,
-    THE_COLLATERAL_CHOSEN_CANNOT_BE_LIQUIDATED,
-  } = ProtocolErrors;
+  const {INVALID_HF} = ProtocolErrors;
 
   it('LIQUIDATION - Deposits WETH, borrows DAI', async () => {
     const {dai, weth, users, pool, oracle} = testEnv;
@@ -67,7 +62,7 @@ makeSuite('LendingPool liquidation - liquidator receiving the underlying asset',
 
     expect(userGlobalDataAfter.currentLiquidationThreshold.toString()).to.be.bignumber.equal(
       '8000',
-      'Invalid liquidation threshold'
+      INVALID_HF
     );
   });
 
@@ -86,7 +81,7 @@ makeSuite('LendingPool liquidation - liquidator receiving the underlying asset',
 
     expect(userGlobalData.healthFactor.toString()).to.be.bignumber.lt(
       oneEther.toFixed(0),
-      'Invalid health factor'
+      INVALID_HF
     );
   });
 
diff --git a/test/stable-token.spec.ts b/test/stable-token.spec.ts
index e6c25573..1d6adcdb 100644
--- a/test/stable-token.spec.ts
+++ b/test/stable-token.spec.ts
@@ -5,7 +5,7 @@ import {getContract} from '../helpers/contracts-helpers';
 import {StableDebtToken} from '../types/StableDebtToken';
 
 makeSuite('Stable debt token tests', (testEnv: TestEnv) => {
-  const {INVALID_POOL_CALLER_MSG_1} = ProtocolErrors;
+  const {CALLER_MUST_BE_LENDING_POOL} = ProtocolErrors;
 
   it('Tries to invoke mint not being the LendingPool', async () => {
     const {deployer, pool, dai} = testEnv;
@@ -19,7 +19,7 @@ makeSuite('Stable debt token tests', (testEnv: TestEnv) => {
     );
 
     await expect(stableDebtContract.mint(deployer.address, '1', '1')).to.be.revertedWith(
-      INVALID_POOL_CALLER_MSG_1
+      CALLER_MUST_BE_LENDING_POOL
     );
   });
 
@@ -35,7 +35,7 @@ makeSuite('Stable debt token tests', (testEnv: TestEnv) => {
     );
 
     await expect(stableDebtContract.burn(deployer.address, '1')).to.be.revertedWith(
-      INVALID_POOL_CALLER_MSG_1
+      CALLER_MUST_BE_LENDING_POOL
     );
   });
 });
diff --git a/test/upgradeability.spec.ts b/test/upgradeability.spec.ts
index 41fc60ea..b2f50179 100644
--- a/test/upgradeability.spec.ts
+++ b/test/upgradeability.spec.ts
@@ -1,18 +1,22 @@
 import {expect} from 'chai';
 import {makeSuite, TestEnv} from './helpers/make-suite';
 import {ProtocolErrors, eContractid} from '../helpers/types';
-import {deployGenericAToken, getAToken, deployContract, getContract} from '../helpers/contracts-helpers';
+import {
+  deployGenericAToken,
+  getAToken,
+  deployContract,
+  getContract,
+} from '../helpers/contracts-helpers';
 import {MockAToken} from '../types/MockAToken';
-import { MockStableDebtToken } from '../types/MockStableDebtToken';
-import { MockVariableDebtToken } from '../types/MockVariableDebtToken';
+import {MockStableDebtToken} from '../types/MockStableDebtToken';
+import {MockVariableDebtToken} from '../types/MockVariableDebtToken';
 
 makeSuite('Upgradeability', (testEnv: TestEnv) => {
-  const {INVALID_POOL_MANAGER_CALLER_MSG} = ProtocolErrors;
+  const {CALLER_NOT_LENDING_POOL_MANAGER} = ProtocolErrors;
   let newATokenAddress: string;
   let newStableTokenAddress: string;
   let newVariableTokenAddress: string;
 
-
   before('deploying instances', async () => {
     const {dai, pool} = testEnv;
     const aTokenInstance = await deployContract<MockAToken>(eContractid.MockAToken, [
@@ -22,24 +26,19 @@ makeSuite('Upgradeability', (testEnv: TestEnv) => {
       'aDAI',
     ]);
 
-    const stableDebtTokenInstance = await deployContract<MockStableDebtToken>(eContractid.MockStableDebtToken, [
-      pool.address,
-      dai.address,
-      'Aave stable debt bearing DAI updated',
-      'stableDebtDAI',
-    ]);
+    const stableDebtTokenInstance = await deployContract<MockStableDebtToken>(
+      eContractid.MockStableDebtToken,
+      [pool.address, dai.address, 'Aave stable debt bearing DAI updated', 'stableDebtDAI']
+    );
 
-    const variableDebtTokenInstance = await deployContract<MockVariableDebtToken>(eContractid.MockVariableDebtToken, [
-      pool.address,
-      dai.address,
-      'Aave variable debt bearing DAI updated',
-      'variableDebtDAI',
-    ]);
+    const variableDebtTokenInstance = await deployContract<MockVariableDebtToken>(
+      eContractid.MockVariableDebtToken,
+      [pool.address, dai.address, 'Aave variable debt bearing DAI updated', 'variableDebtDAI']
+    );
 
     newATokenAddress = aTokenInstance.address;
     newVariableTokenAddress = variableDebtTokenInstance.address;
     newStableTokenAddress = stableDebtTokenInstance.address;
-
   });
 
   it('Tries to update the DAI Atoken implementation with a different address than the lendingPoolManager', async () => {
@@ -47,7 +46,7 @@ makeSuite('Upgradeability', (testEnv: TestEnv) => {
 
     await expect(
       configurator.connect(users[1].signer).updateAToken(dai.address, newATokenAddress)
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Upgrades the DAI Atoken implementation ', async () => {
@@ -66,8 +65,10 @@ makeSuite('Upgradeability', (testEnv: TestEnv) => {
     const {dai, configurator, users} = testEnv;
 
     await expect(
-      configurator.connect(users[1].signer).updateStableDebtToken(dai.address, newStableTokenAddress)
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      configurator
+        .connect(users[1].signer)
+        .updateStableDebtToken(dai.address, newStableTokenAddress)
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Upgrades the DAI stable debt token implementation ', async () => {
@@ -79,7 +80,10 @@ makeSuite('Upgradeability', (testEnv: TestEnv) => {
 
     const {stableDebtTokenAddress} = await pool.getReserveTokensAddresses(dai.address);
 
-    const debtToken = await getContract<MockStableDebtToken>(eContractid.MockStableDebtToken, stableDebtTokenAddress);
+    const debtToken = await getContract<MockStableDebtToken>(
+      eContractid.MockStableDebtToken,
+      stableDebtTokenAddress
+    );
 
     const tokenName = await debtToken.name();
 
@@ -90,8 +94,10 @@ makeSuite('Upgradeability', (testEnv: TestEnv) => {
     const {dai, configurator, users} = testEnv;
 
     await expect(
-      configurator.connect(users[1].signer).updateVariableDebtToken(dai.address, newVariableTokenAddress)
-    ).to.be.revertedWith(INVALID_POOL_MANAGER_CALLER_MSG);
+      configurator
+        .connect(users[1].signer)
+        .updateVariableDebtToken(dai.address, newVariableTokenAddress)
+    ).to.be.revertedWith(CALLER_NOT_LENDING_POOL_MANAGER);
   });
 
   it('Upgrades the DAI variable debt token implementation ', async () => {
@@ -103,11 +109,13 @@ makeSuite('Upgradeability', (testEnv: TestEnv) => {
 
     const {variableDebtTokenAddress} = await pool.getReserveTokensAddresses(dai.address);
 
-    const debtToken = await getContract<MockStableDebtToken>(eContractid.MockStableDebtToken, variableDebtTokenAddress);
+    const debtToken = await getContract<MockStableDebtToken>(
+      eContractid.MockStableDebtToken,
+      variableDebtTokenAddress
+    );
 
     const tokenName = await debtToken.name();
 
     expect(tokenName).to.be.eq('Aave variable debt bearing DAI updated', 'Invalid token name');
   });
-
 });
diff --git a/test/variable-debt-token.spec.ts b/test/variable-debt-token.spec.ts
index 28b35849..89bb1acc 100644
--- a/test/variable-debt-token.spec.ts
+++ b/test/variable-debt-token.spec.ts
@@ -5,7 +5,7 @@ import {getContract} from '../helpers/contracts-helpers';
 import {VariableDebtToken} from '../types/VariableDebtToken';
 
 makeSuite('Variable debt token tests', (testEnv: TestEnv) => {
-  const {INVALID_POOL_CALLER_MSG_1} = ProtocolErrors;
+  const {CALLER_MUST_BE_LENDING_POOL} = ProtocolErrors;
 
   it('Tries to invoke mint not being the LendingPool', async () => {
     const {deployer, pool, dai} = testEnv;
@@ -19,7 +19,7 @@ makeSuite('Variable debt token tests', (testEnv: TestEnv) => {
     );
 
     await expect(variableDebtContract.mint(deployer.address, '1')).to.be.revertedWith(
-      INVALID_POOL_CALLER_MSG_1
+      CALLER_MUST_BE_LENDING_POOL
     );
   });
 
@@ -35,7 +35,7 @@ makeSuite('Variable debt token tests', (testEnv: TestEnv) => {
     );
 
     await expect(variableDebtContract.burn(deployer.address, '1')).to.be.revertedWith(
-      INVALID_POOL_CALLER_MSG_1
+      CALLER_MUST_BE_LENDING_POOL
     );
   });
 });