What Is Brownie?

Brownie was built to give Python developers an alternative to JavaScript-based tools such as Truffle and Hardhat. It can compile contracts written in Solidity and Vyper, run them on a local test blockchain (usually Ganache), and deploy them to testnets or the mainnet. Users can interact with contracts through an interactive Python console and automation scripts.

Tests are written with pytest, a library widely used in the Python world, which shortens the learning curve for developers who already know Python. Brownie also offers features such as forking a copy of the mainnet locally to test against real protocols, generating transaction traces for debugging, and measuring test coverage. For example, a developer can test on a mainnet fork whether a DeFi contract they wrote interacts correctly with Uniswap.

Brownie's maintenance has been officially abandoned, and the project team has recommended Ape Framework to Python developers. New projects generally prefer actively developed tools such as Foundry, Hardhat or Ape. Scripts written with Brownie can still be encountered in older projects; keep in mind that unmaintained tools may become incompatible with current Solidity versions and network changes.