diff --git a/src/main/kotlin/org/ethereum/lists/chains/Env.kt b/src/main/kotlin/org/ethereum/lists/chains/Env.kt
index 2d8824d9..f96c8d02 100644
--- a/src/main/kotlin/org/ethereum/lists/chains/Env.kt
+++ b/src/main/kotlin/org/ethereum/lists/chains/Env.kt
@@ -1,7 +1,9 @@
 package org.ethereum.lists.chains
 
+import com.squareup.moshi.JsonAdapter
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
+import org.ethereum.lists.chains.model.Chain
 
 val mandatory_fields = listOf(
         "name",
@@ -21,3 +23,4 @@ val optionalFields = listOf(
 )
 
 val moshi: Moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
+val chainAdapter: JsonAdapter<Chain> = moshi.adapter(Chain::class.java)
diff --git a/src/main/kotlin/org/ethereum/lists/chains/Main.kt b/src/main/kotlin/org/ethereum/lists/chains/Main.kt
index 952e2e9b..aafde6bd 100644
--- a/src/main/kotlin/org/ethereum/lists/chains/Main.kt
+++ b/src/main/kotlin/org/ethereum/lists/chains/Main.kt
@@ -8,6 +8,9 @@ import org.kethereum.erc55.isValid
 import org.kethereum.model.Address
 import org.kethereum.rpc.HttpEthereumRPC
 
+val parsedShortNames= mutableSetOf<String>()
+val parsedNames= mutableSetOf<String>()
+
 fun main(args: Array<String>) {
 
     File("_data/chains").listFiles()?.forEach {
@@ -83,7 +86,16 @@ moshi fails for extra commas
 https://github.com/ethereum-lists/chains/issues/126
 */
 private fun parseWithMoshi(fileToParse: File) {
-    moshi.adapter(Chain::class.java).fromJson(fileToParse.readText())
+    val parsedChain = chainAdapter.fromJson(fileToParse.readText())
+    if (parsedNames.contains(parsedChain!!.name)) {
+        throw NameMustBeUnique(parsedChain.name)
+    }
+    parsedNames.add(parsedChain.name)
+
+    if (parsedShortNames.contains(parsedChain.shortName)) {
+        throw ShortNameMustBeUnique(parsedChain.shortName)
+    }
+    parsedShortNames.add(parsedChain.shortName)
 }
 
 private fun getNumber(jsonObject: JsonObject, field: String): Long {
diff --git a/src/main/kotlin/org/ethereum/lists/chains/model/Exceptions.kt b/src/main/kotlin/org/ethereum/lists/chains/model/Exceptions.kt
index e02fc556..39b89769 100644
--- a/src/main/kotlin/org/ethereum/lists/chains/model/Exceptions.kt
+++ b/src/main/kotlin/org/ethereum/lists/chains/model/Exceptions.kt
@@ -9,3 +9,5 @@ class RPCMustBeListOfStrings : Exception("rpc must be a list of strings")
 class ENSMustBeObject: Exception("ens must be an object")
 class ENSMustHaveOnlyRegistry: Exception("ens can only have a registry currently")
 class ENSRegistryAddressMustBeValid: Exception("ens registry must have valid address")
+class NameMustBeUnique(dup: String): Exception(" name must be unique - but found `$dup` more than once")
+class ShortNameMustBeUnique(dup: String): Exception("short name must be unique - but found `$dup` more than once")
\ No newline at end of file
diff --git a/src/test/kotlin/TheChainChecker.kt b/src/test/kotlin/TheChainChecker.kt
index c1c2ccf6..8f8b9910 100644
--- a/src/test/kotlin/TheChainChecker.kt
+++ b/src/test/kotlin/TheChainChecker.kt
@@ -1,11 +1,18 @@
 import com.squareup.moshi.JsonEncodingException
 import org.ethereum.lists.chains.*
 import org.ethereum.lists.chains.model.*
+import org.junit.Before
 import org.junit.Test
 import java.io.File
 
 class TheChainChecker {
 
+    @Before
+    fun setup() {
+        parsedNames.clear()
+        parsedShortNames.clear()
+    }
+
     @Test
     fun shouldPassForValidChain() {
         val file = getFile("valid/1.json")
@@ -84,6 +91,23 @@ class TheChainChecker {
         checkChain(file, false)
     }
 
+    @Test(expected = NameMustBeUnique::class)
+    fun shouldFailOnNonUniqueName() {
+        checkChain(getFile("valid/1.json"), false)
+        checkChain(getFile("valid/1.json"), false)
+    }
+
+    @Test(expected = ShortNameMustBeUnique::class)
+    fun shouldFailOnNonUniqueShortName() {
+        checkChain(getFile("invalid/sameshortname/5.json"), false)
+        checkChain(getFile("invalid/sameshortname/1.json"), false)
+    }
+
+    @Test
+    fun canParse2chains() {
+        checkChain(getFile("valid/1.json"), false)
+        checkChain(getFile("valid/5.json"), false)
+    }
 
     private fun getFile(s: String) = File(javaClass.classLoader.getResource("test_chains/$s").file)
 
diff --git a/src/test/resources/test_chains/invalid/sameshortname/1.json b/src/test/resources/test_chains/invalid/sameshortname/1.json
new file mode 100644
index 00000000..d3f9eee1
--- /dev/null
+++ b/src/test/resources/test_chains/invalid/sameshortname/1.json
@@ -0,0 +1,14 @@
+{
+  "name": "Ethereum Mainnet",
+  "shortName": "willfail",
+  "chain": "ETH",
+  "network": "mainnet",
+  "chainId": 1,
+  "networkId": 1,
+  "rpc": [
+    "https://mainnet.infura.io/v3/${INFURA_API_KEY}",
+    "https://api.mycryptoapi.com/eth"
+  ],
+  "faucets": [],
+  "infoURL": "https://ethereum.org"
+}
diff --git a/src/test/resources/test_chains/invalid/sameshortname/5.json b/src/test/resources/test_chains/invalid/sameshortname/5.json
new file mode 100644
index 00000000..d479df95
--- /dev/null
+++ b/src/test/resources/test_chains/invalid/sameshortname/5.json
@@ -0,0 +1,26 @@
+{
+  "name": "Ethereum Testnet Görli",
+  "chain": "ETH",
+  "network": "goerli",
+  "rpc": [
+    "https://rpc.goerli.mudit.blog/",
+    "https://rpc.slock.it/goerli ",
+    "https://goerli.prylabs.net"
+  ],
+  "faucets": [
+    "https://goerli-faucet.slock.it/?address=${ADDRESS}",
+    "https://faucet.goerli.mudit.blog"
+  ],
+  "nativeCurrency": {
+    "name": "Görli Ether",
+    "symbol": "GOR",
+    "decimals": 18
+  },
+  "infoURL": "https://goerli.net/#about",
+  "shortName": "willfail",
+  "chainId": 5,
+  "networkId": 5,
+  "ens": {
+    "registry":"0x112234455c3a32fd11230c42e7bccd4a84e02010"
+  }
+}