ProofRails
ProofRails

Make onchain payments finance-ready.

Turn onchain payments and paid API calls into receipts, delivery evidence, ISO 20022-style artifacts, signed evidence bundles and verifiable onchain commitments.

Use the APIHow it worksUnderstand x402
RECEIPT API
POST /v1/iso/record-tip

{
  "tip_tx_hash": "0x…",
  "chain": "flare",
  "amount": "12.50",
  "currency": "USD₮0",
  "reference": "order-1842"
}

receipt_id · evidence.zip · bundle_hash

A blockchain transaction proves that value moved. It does not explain the purchase, identify the delivered API result, or produce the records that finance and operations teams need.

ProofRails accepts a settlement reference and business context, then creates a receipt with linked evidence. The same engine can process a payment submitted through the Receipt API or a paid API call completed through x402.

Payment sources enter the ProofRails evidence engine and produce receipts, financial artifacts, signed evidence and an onchain commitment

What ProofRails produces

Output Purpose Where to access it
Receipt Connects the payment, parties, amount, chain, business reference and processing state. Hosted app, public receipt page or Receipts API.
Delivery evidence Binds a purchased file or API response to the receipt with a SHA-256 resource hash when one is supplied or generated. Receipt and evidence bundle.
ISO 20022-style artifacts Maps receipt data into finance-readable payment and reporting files. Artifact API and evidence files.
Signed evidence bundle Packages the receipt, manifest, file hashes, signature and public key into a portable ZIP. Receipt bundle_url.
Onchain commitment Commits the current bundle hash through EvidenceAnchor on Flare. Receipt anchor transaction and public verifier.
Verification result Recomputes the bundle hash and compares it with the committed value. Public verifier or Verification API.

The engine and the hosted service

The ProofRails engine performs normalization, artifact generation, hashing, signing, anchoring and verification. The hosted service runs that engine for you and adds API authentication, storage, background workers, receipt pages and a public verifier.

You can also run the source yourself and configure your own storage, projects, keys and contracts.

Where x402 fits

x402 is a payment protocol for HTTP resources. A server returns HTTP 402 with payment requirements, an x402 client authorizes the payment, and the client retries the request.

ProofRails uses x402 as one way to trigger the evidence engine. After a paid request succeeds, ProofRails records the settlement, hashes the returned resource, creates the receipt and evidence bundle, and anchors the bundle hash. x402 handles the payment exchange. ProofRails handles the business record that remains afterward.

The current hosted x402 path uses real USD₮0 on Flare mainnet. Read x402 and ProofRails before sending a paid request.

Choose a starting point

If you want to... Start here
Record an existing onchain payment Create a receipt
Add receipts to an application Hosted API quickstart
Verify a receipt without credentials Verify a receipt
Build an agent that pays for an API x402 client integration
Understand the processing engine Evidence engine
Inspect contracts and events Flare contracts
Give an AI coding agent complete context Machine-readable documentation

ProofRails uses the term ISO 20022-style artifacts. It does not claim that generated files are certified for a particular institution or market practice.