diff --git a/tests/erc1155/transfer-batch-handler.test.ts b/tests/erc1155/transfer-batch-handler.test.ts
index ab4b9fc..feba0f0 100644
--- a/tests/erc1155/transfer-batch-handler.test.ts
+++ b/tests/erc1155/transfer-batch-handler.test.ts
@@ -24,7 +24,7 @@ describe('ERC-1155 Transfer Batch Handler', () => {
         assert.fieldEquals('Nft', _id, 'tokenId', TokenIds[i].toString())
         assert.fieldEquals('Nft', _id, 'owner', Addresses[1])
         assert.fieldEquals('Nft', _id, 'amount', Amounts[i].toString())
-        assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155.toString())
+        assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155)
       }
     })
 
@@ -45,7 +45,7 @@ describe('ERC-1155 Transfer Batch Handler', () => {
         assert.fieldEquals('Nft', _id, 'tokenId', TokenIds[i].toString())
         assert.fieldEquals('Nft', _id, 'owner', Addresses[1])
         assert.fieldEquals('Nft', _id, 'amount', Amounts[i].toString())
-        assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155.toString())
+        assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155)
       }
     })
   })
@@ -68,7 +68,7 @@ describe('ERC-1155 Transfer Batch Handler', () => {
         assert.fieldEquals('Nft', _id, 'tokenId', TokenIds[i].toString())
         assert.fieldEquals('Nft', _id, 'owner', Addresses[1])
         assert.fieldEquals('Nft', _id, 'amount', Amounts[i].toString())
-        assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155.toString())
+        assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155)
       }
     })
 
@@ -82,7 +82,7 @@ describe('ERC-1155 Transfer Batch Handler', () => {
         assert.fieldEquals('Nft', _id, 'tokenId', TokenIds[i].toString())
         assert.fieldEquals('Nft', _id, 'owner', Addresses[1])
         assert.fieldEquals('Nft', _id, 'amount', Amounts[i].toString())
-        assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155.toString())
+        assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155)
       }
 
       const event2 = createTransferBatchEvent(Addresses[0], Addresses[1], Addresses[2], TokenIds, Amounts, ZERO_ADDRESS)
@@ -94,7 +94,7 @@ describe('ERC-1155 Transfer Batch Handler', () => {
         assert.fieldEquals('Nft', _id2, 'tokenId', TokenIds[i].toString())
         assert.fieldEquals('Nft', _id2, 'owner', Addresses[2])
         assert.fieldEquals('Nft', _id2, 'amount', Amounts[i].toString())
-        assert.fieldEquals('Nft', _id2, 'type', NftType.ERC1155.toString())
+        assert.fieldEquals('Nft', _id2, 'type', NftType.ERC1155)
       }
     })
   })
diff --git a/tests/erc1155/transfer-single-handler.test.ts b/tests/erc1155/transfer-single-handler.test.ts
index b9d0b64..1a6b7f2 100644
--- a/tests/erc1155/transfer-single-handler.test.ts
+++ b/tests/erc1155/transfer-single-handler.test.ts
@@ -28,7 +28,7 @@ describe('ERC-1155 Transfer Single Handler', () => {
       assert.fieldEquals('Nft', _id, 'tokenId', TokenIds[0].toString())
       assert.fieldEquals('Nft', _id, 'owner', Addresses[1])
       assert.fieldEquals('Nft', _id, 'amount', Amounts[0].toString())
-      assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155.toString())
+      assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155)
     })
 
     test('should transfer NFT and create Account when NFT exist Account does not', () => {
@@ -53,7 +53,7 @@ describe('ERC-1155 Transfer Single Handler', () => {
       assert.fieldEquals('Nft', _id, 'tokenId', TokenIds[0].toString())
       assert.fieldEquals('Nft', _id, 'owner', Addresses[1])
       assert.fieldEquals('Nft', _id, 'amount', Amounts[0].toString())
-      assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155.toString())
+      assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155)
     })
   })
   describe('When NFT or Account exists', () => {
@@ -79,7 +79,7 @@ describe('ERC-1155 Transfer Single Handler', () => {
       assert.fieldEquals('Nft', _id, 'tokenId', TokenIds[0].toString())
       assert.fieldEquals('Nft', _id, 'owner', Addresses[1])
       assert.fieldEquals('Nft', _id, 'amount', Amounts[0].toString())
-      assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155.toString())
+      assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155)
     })
 
     test('should transfer NFT and update amount after two transfers', () => {
@@ -98,7 +98,7 @@ describe('ERC-1155 Transfer Single Handler', () => {
       assert.fieldEquals('Nft', _id, 'tokenId', TokenIds[0].toString())
       assert.fieldEquals('Nft', _id, 'owner', Addresses[1])
       assert.fieldEquals('Nft', _id, 'amount', Amounts[1].toString())
-      assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155.toString())
+      assert.fieldEquals('Nft', _id, 'type', NftType.ERC1155)
 
       const event2 = createTransferSingleEvent(
         Addresses[0],
@@ -115,7 +115,7 @@ describe('ERC-1155 Transfer Single Handler', () => {
       assert.fieldEquals('Nft', _id2, 'tokenId', TokenIds[0].toString())
       assert.fieldEquals('Nft', _id2, 'owner', Addresses[2])
       assert.fieldEquals('Nft', _id2, 'amount', Amounts[0].toString())
-      assert.fieldEquals('Nft', _id2, 'type', NftType.ERC1155.toString())
+      assert.fieldEquals('Nft', _id2, 'type', NftType.ERC1155)
     })
   })
 })
diff --git a/tests/helpers/entities.ts b/tests/helpers/entities.ts
index 9df4c30..afeb501 100644
--- a/tests/helpers/entities.ts
+++ b/tests/helpers/entities.ts
@@ -14,7 +14,7 @@ export function createMockNft(tokenAddress: string, tokenId: string, ownerAddres
   const nft = new Nft(generateERC721NftId(tokenAddress, BigInt.fromString(tokenId)))
   nft.tokenAddress = tokenAddress
   nft.tokenId = BigInt.fromString(tokenId)
-  nft.type = NftType.ERC721.toString()
+  nft.type = NftType.ERC721
 
   const nftOwner = createMockAccount(ownerAddress)
 
diff --git a/utils/entities/nft/erc-1155.ts b/utils/entities/nft/erc-1155.ts
index d2af597..f266f9d 100644
--- a/utils/entities/nft/erc-1155.ts
+++ b/utils/entities/nft/erc-1155.ts
@@ -16,7 +16,7 @@ export function upsertERC1155Nft(tokenAddress: string, tokenId: BigInt, amount:
     nft.tokenId = tokenId
     nft.tokenAddress = tokenAddress
     nft.owner = findOrCreateAccount(to).id
-    nft.type = NftType.ERC1155.toString()
+    nft.type = NftType.ERC1155
   }
 
   return updateERC1155Balance(findOrCreateAccount(from), findOrCreateAccount(to), nft, amount)
@@ -30,7 +30,7 @@ export function findOrCreateERC1155Nft(tokenAddress: string, tokenId: BigInt, to
     nft = new Nft(nftId)
     nft.tokenId = tokenId
     nft.tokenAddress = tokenAddress
-    nft.type = NftType.ERC1155.toString()
+    nft.type = NftType.ERC1155
     nft.owner = to.id
     nft.save()
   }
diff --git a/utils/entities/nft/erc-721.ts b/utils/entities/nft/erc-721.ts
index 5b6160c..c917c6a 100644
--- a/utils/entities/nft/erc-721.ts
+++ b/utils/entities/nft/erc-721.ts
@@ -1,5 +1,5 @@
-import { NftType } from '../../enums'
 import { Nft } from '../../../generated/schema'
+import { NftType } from '../../enums'
 import { findOrCreateAccount } from '../account'
 import { BigInt } from '@graphprotocol/graph-ts'
 
@@ -14,7 +14,7 @@ export function upsertERC721Nft(tokenAddress: string, tokenId: BigInt, to: strin
     nft = new Nft(nftId)
     nft.tokenId = tokenId
     nft.tokenAddress = tokenAddress
-    nft.type = NftType.ERC721.toString()
+    nft.type = NftType.ERC721
   }
 
   nft.owner = findOrCreateAccount(to).id
diff --git a/utils/enums/nft.ts b/utils/enums/nft.ts
index 8e24bfe..e7dbff6 100644
--- a/utils/enums/nft.ts
+++ b/utils/enums/nft.ts
@@ -1,4 +1,7 @@
-export enum NftType {
-  ERC721,
-  ERC1155,
+// We are using a class instead of an enum because we need to use the values as string, but we need to map it enum alike
+export class NftType {
+  // eslint-disable-next-line @typescript-eslint/no-inferrable-types
+  static ERC721: string = 'ERC721'
+  // eslint-disable-next-line @typescript-eslint/no-inferrable-types
+  static ERC1155: string = 'ERC1155'
 }