Celo Builder Codes

ERC-8021 builder-code attribution on Celo. One small suffix at the end of a transaction makes it identifiable as having come through your app.

Built for, in priority order: MiniPay apps, Proof of Ship cohort projects, and Celo ecosystem projects more broadly. Celo-only — ERC-8021 is the standard we conform to, nothing more.

Pick the doc for your role

• You're shipping an app on Celo and want your transactions attributed? → BUILDERS.md
• You're writing a parser, indexer, or Dune model that reads tagged Celo transactions? → INDEXERS.md

What's in this repo

.
├── README.md                      (this overview)
├── BUILDERS.md                    (for app builders)
├── INDEXERS.md                    (for parsers, indexers, Dune models)
├── sdk/                           (the npm package — @celo/builder-codes)
│   ├── src/index.ts
│   ├── tests/
│   ├── package.json
│   └── README.md                  (full SDK API reference)
├── docs/
│   └── integration-reports/
│       └── mondeto.md             (first real consumer integration)
└── .claude/commands/              (Claude Code slash commands for testing)

Status

The SDK is published on npm as @celo/builder-codes. The wire format and derivation algorithm are stable.

Contact

Lena Hierzi (DevRel Lead, Celo Core Co) — file an issue or reach out on Telegram / Discord.

License

MIT.