Devcon 8: Build Battle 2

Devcon 8 · Build Battle 2: Pay It Upstream

Build Battle 2 is a 24-hour build sprint around one problem. You build in your own public GitHub repo, and an AI judge reads your code against the brief and the rubric. It never runs the code. The checks and their point values are on the problem page, so you can see what counts as good before you write a line.

The challenge

Open source runs the internet, and the money rarely reaches the people doing the work. Sponsorship lands in one maintainer's personal account. Contributors get paid by hand, late, or not at all. The libraries underneath get nothing.

Pick a real open-source project, or start from the maintainer in the brief, and build the mechanism that fixes this: one address sponsors can pay, a split anyone can read, and a way for every contributor and upstream project to collect what they're owed.

The test is simple: the maintainer never touches the money, and nobody, including the maintainer, can quietly keep what belongs to someone else.

Build it on Ethereum

Smart contracts are a good fit for this. The rules are public, the money moves by code rather than by promise, and anyone can check the balances. Here's what's worth knowing for this battle:

• Pull, don't push: credit each recipient's balance and let them withdraw. If you loop over recipients and send to each, one bad address can block everyone.
• Money maths is integer maths: shares in basis points, amounts in wei, and integer division leaves remainders. Decide where every last wei goes.
• Guard the exit: update balances before sending funds, or use a reentrancy guard. Make sure no admin function can sweep funds that are owed to recipients.
• Make it readable: sponsors and contributors aren't Solidity developers. Show them the split and their balance in plain language, read straight from the contract.
• Prior art: Drips already splits open-source funding to maintainers and dependencies on Ethereum. Read it for ideas. Your own repo must contain the funds-handling logic.
• Tooling: Solidity, Foundry, OpenZeppelin Contracts, viem and wagmi, with TypeScript and Vite. Deploy to Sepolia.

You can update your entry until the deadline. Join the challenge now.