diff --git a/CHANGELOG.md b/CHANGELOG.md
index 50a17d73..cee57563 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - translation of cost models from numerical IDs to strings,
   required for `cardano-db-sync 13.1.1.3` and newer [#130](https://github.com/blockfrost/blockfrost-backend-ryo/pull/130)
 - indices improving `/assets/{asset}` when querying CIP68 assets and `/txs/{tx_hash}` with redeemers
+- IS_LOCAL env for testing
 
 ### Changed
 
diff --git a/default.nix b/default.nix
index 5f34c531..3a63d662 100644
--- a/default.nix
+++ b/default.nix
@@ -91,7 +91,7 @@ in
       machine.wait_for_open_port(3000)
       machine.succeed("cp -r ${blockfrost-tests} /tmp/tests")
       machine.succeed(
-          "cd /tmp/tests && NIX_PATH=nixpkgs=${nixpkgs} nix-shell --run 'SERVER_URL=http://localhost:3000/ TEST_AUTH=false IS_CACHED=true yarn test:mainnet --run' >&2"
+          "cd /tmp/tests && NIX_PATH=nixpkgs=${nixpkgs} nix-shell --run 'SERVER_URL=http://localhost:3000/ IS_LOCAL=true TEST_AUTH=false IS_CACHED=true yarn test:mainnet --run' >&2"
       )
     '';
   };
@@ -127,7 +127,7 @@ in
       machine.wait_for_open_port(3000)
       machine.succeed("cp -r ${blockfrost-tests} /tmp/tests")
       machine.succeed(
-          "cd /tmp/tests && NIX_PATH=nixpkgs=${nixpkgs} nix-shell --run 'SERVER_URL=http://localhost:3000/ TEST_AUTH=false IS_CACHED=true yarn test:preview --run' >&2"
+          "cd /tmp/tests && NIX_PATH=nixpkgs=${nixpkgs} nix-shell --run 'SERVER_URL=http://localhost:3000/ IS_LOCAL=true TEST_AUTH=false IS_CACHED=true yarn test:preview --run' >&2"
       )
     '';
   };
@@ -163,7 +163,7 @@ in
       machine.wait_for_open_port(3000)
       machine.succeed("cp -r ${blockfrost-tests} /tmp/tests")
       machine.succeed(
-          "cd /tmp/tests && NIX_PATH=nixpkgs=${nixpkgs} nix-shell --run 'SERVER_URL=http://localhost:3000/ TEST_AUTH=false IS_CACHED=true yarn test:preprod --run' >&2"
+          "cd /tmp/tests && NIX_PATH=nixpkgs=${nixpkgs} nix-shell --run 'SERVER_URL=http://localhost:3000/ IS_LOCAL=true TEST_AUTH=false IS_CACHED=true yarn test:preprod --run' >&2"
       )
     '';
   };