^{Originally posted by @TSKHot July 7, 2025}
We're trying to test our ERC-4337 based contracts. So far we've been using Geth running in dev mode with the Stackup Bundler running in private mode. Everything works successfully - contract deployment, making direct contract calls, submitting user operations through Stackup, etc.

Now we need to start testing using a mainnet fork (to add functionality for interacting with on-chain DAOs such as Uniswap), so we're trying to use Anvil (v1.2.3-stable). However, when running against the Anvil node and submitting user operations via Stackup we're getting the error "Error: Invalid params: unsupported tracer type".

Can anyone tell me if there's a way around this?