fee-payer

Fee Payer Service

A Cloudflare Worker that provides fee sponsorship for Tempo transactions.

cp .env.example .env  # Copy example environment variables
pnpm install          # Install dependencies
pnpm dev              # Start development server
pnpm dev:playground   # Start playground

Testing

pnpm test                            # Run integration tests (requires Docker)
TEMPO_ENV=moderato pnpm test         # Run tests against moderato (42431)

Tests use Cloudflare's vitest-pool-workers to run the Worker in a local Miniflare environment.

Transaction sponsorship tests require a local Tempo node. The test setup automatically starts a Tempo container via Prool when Docker is running. No manual setup is required - the sponsor account is derived from a deterministic test mnemonic and is pre-funded on localnet.

Environment variables:

• TEMPO_ENV - localnet (default), moderato, or devnet (testnet is accepted as a backwards-compatible alias of moderato)
• TEMPO_TAG - Docker image tag for localnet (default: latest)

API

Method	Route	Params
GET	/usage	- optional: blockTimestampFrom (epoch seconds) - optional: blockTimestampTo (epoch seconds)
POST	*	JSON-RPC request body for fee sponsorship Supported methods: eth_signTransaction, eth_signRawTransaction, eth_sendRawTransaction, eth_sendRawTransactionSync