diff --git a/packages/contracts/evm-contracts/contracts/token/InverseAppProjected1155.sol b/packages/contracts/evm-contracts/contracts/token/InverseAppProjected1155.sol
index b2298802c..6e435f306 100644
--- a/packages/contracts/evm-contracts/contracts/token/InverseAppProjected1155.sol
+++ b/packages/contracts/evm-contracts/contracts/token/InverseAppProjected1155.sol
@@ -45,6 +45,7 @@ contract InverseAppProjected1155 is IInverseAppProjected1155, ERC1155Supply, Own
         name = _name;
         symbol = _symbol;
         currentTokenId = 1;
+        baseExtension = ".json";
     }
 
     /// @dev Returns true if this contract implements the interface defined by `interfaceId`. See EIP165.
diff --git a/packages/contracts/evm-contracts/contracts/token/InverseBaseProjected1155.sol b/packages/contracts/evm-contracts/contracts/token/InverseBaseProjected1155.sol
index e52ce34e2..e90a81fb4 100644
--- a/packages/contracts/evm-contracts/contracts/token/InverseBaseProjected1155.sol
+++ b/packages/contracts/evm-contracts/contracts/token/InverseBaseProjected1155.sol
@@ -36,6 +36,7 @@ contract InverseBaseProjected1155 is IInverseBaseProjected1155, ERC1155Supply, O
         name = _name;
         symbol = _symbol;
         currentTokenId = 1;
+        baseExtension = ".json";
     }
 
     /// @dev Returns true if this contract implements the interface defined by `interfaceId`. See EIP165.
diff --git a/packages/contracts/evm-contracts/test/InverseAppProjected1155.t.sol b/packages/contracts/evm-contracts/test/InverseAppProjected1155.t.sol
index 719d0a3cb..a38b40f0d 100644
--- a/packages/contracts/evm-contracts/test/InverseAppProjected1155.t.sol
+++ b/packages/contracts/evm-contracts/test/InverseAppProjected1155.t.sol
@@ -135,7 +135,8 @@ contract InverseAppProjected1155Test is CTest, ERC1155Holder {
                 "/",
                 userTokenId.toString(),
                 "/",
-                value.toString()
+                value.toString(),
+                ".json"
             )
         );
     }
@@ -158,7 +159,8 @@ contract InverseAppProjected1155Test is CTest, ERC1155Holder {
                 "/",
                 userTokenId.toString(),
                 "/",
-                value.toString()
+                value.toString(),
+                ".json"
             )
         );
     }
diff --git a/packages/contracts/evm-contracts/test/InverseBaseProjected1155.t.sol b/packages/contracts/evm-contracts/test/InverseBaseProjected1155.t.sol
index a3261a5c1..d17627717 100644
--- a/packages/contracts/evm-contracts/test/InverseBaseProjected1155.t.sol
+++ b/packages/contracts/evm-contracts/test/InverseBaseProjected1155.t.sol
@@ -100,7 +100,14 @@ contract InverseBaseProjected1155Test is CTest, ERC1155Holder {
         string memory result = token.uri(tokenId);
         assertEq(
             result,
-            string.concat(baseURI, "eip155:", block.chainid.toString(), "/", tokenId.toString())
+            string.concat(
+                baseURI,
+                "eip155:",
+                block.chainid.toString(),
+                "/",
+                tokenId.toString(),
+                ".json"
+            )
         );
     }
 
@@ -111,7 +118,14 @@ contract InverseBaseProjected1155Test is CTest, ERC1155Holder {
         string memory result = token.uri(tokenId, customUri);
         assertEq(
             result,
-            string.concat(customUri, "eip155:", block.chainid.toString(), "/", tokenId.toString())
+            string.concat(
+                customUri,
+                "eip155:",
+                block.chainid.toString(),
+                "/",
+                tokenId.toString(),
+                ".json"
+            )
         );
     }