We build developer infrastructure at the boundary where code becomes execution.
Together with Ethereum Foundation & Argot Collective,
we lead the implementation of ETHDebug in solc, the Solidity compiler.
Tools for inspecting, testing, and reproducing transaction execution.
Debugger for Miden.
Debugger for EVM & Starknet.
CLI debugger for MultiVM.
Compilers and intermediate representations for turning code into executable programs.
The Solidity compiler.
Frontends for navigating and understanding onchain activity.
Open-source block explorer for Superchain.
Interactive environments for writing and running programs.
Interactive playground for Miden VM.
Web playground for the CairoVM.
“Transaction Debugging and Simulations are a big missing piece on Starknet, so it’s great to see Walnut providing developers with these essential tools.”
“Debugger and transaction simulator is a big missing piece in Starknet. At Argent, we are excited that this gap is being filled with Walnut.”
“Debugging or simulating transactions is an absolutely critical task for any on-chain developer. We cannot wait to have Walnut integrated with Karnot and Madara Appchains.”
“Debugging transactions and performance monitoring are pain points on Starknet today. Every DeFi protocol builder woud benefit from better tooling, and it’s great to see Walnut addressing this need.”
“I think Walnut is very important and that you [the Walnut team] are doing very valuable work for Starknet.”
“Walnut is an essential tool for debugging complex transactions with nested calls and large amounts of calldata. Walnut helped me with a massive blocker on the Bitcoin inscriptions project. 🌰”
“At Cartridge, we see a lot of interest in transaction debugging and simulation. Walnut has the potential to become a critical tool for game developers building on Starknet.”
“With Enso, we are not yet on Starknet. However, seeing a debugger and simulator like Walnut is a great testament to Starknet’s maturing devtools ecosystem, making it more appealing to new developers. We need a debugger and simulator to ship anything on Starknet, as we rely on this tooling in all EVM ecosystems and cannot build without it.”
“We are thrilled about the Walnut integration with Dojo. Step-by-step debugging with instant replay of transactions will be another string to the bow for all the sensei building on Dojo.”
“At Nimbora, we are big supporters of Walnut and the transaction debugger and simulator for Starknet. We are looking forward to using it with Nimbora and integrating it with Devnet and Rivet, our new developer-focused wallet.”
“Had to debug an OpenZeppelin tx on Starknet Sepolia—Walnut made it way too easy. Lifesaver!”
Vesu uses Walnut Debugger to trace transactions, step through execution, and catch issues before they ship.
Miden is a leading project bringing privacy to Ethereum, and we've been working with the team for over a year. This post covers our contributions to the Miden ecosystem during Q1 2026.
If you've ever looked at a Starknet transaction and wondered where all the gas goes — we’ve got the answer.
Starknet is an ecosystem that made a bold decision: it launched with its own custom language—Cairo. That means, among other things, it had to build everything from scratch. Cairo devs couldn’t rely on any of the existing blockchain tooling available for Solidity, Ethereum, or other blockchain ecosystems.
