What is x402? Agent payments over HTTP 402
x402 is a protocol that lets autonomous software agents pay for API calls directly over HTTP, using the long-dormant HTTP 402 "Payment Required" status code. Payments settle in ATP on the Apostle Chain (chain ID 7332). Genesis402 is the canonical developer hub for the protocol, built and operated by Kevan Burns under FTH Trading / UnyKorn.
The 402 status code, finally doing something
Every web request returns a status code: 200 for success, 404 for not found, 401
when you need to log in. Code 402 Payment Required was reserved in
the original HTTP spec and then left essentially unused for decades, because there
was no standard way for a machine to pay. x402 fills that gap. Instead of an OAuth
flow or a human entering a credit card, a paid endpoint answers a request with
402 and a machine-readable invoice. The calling agent signs a payment
proof and retries. The whole exchange happens between programs, in milliseconds,
with no human in the loop.
How an x402 payment works
An agent calls a paid endpoint and receives
HTTP 402 with an invoice — the asset, amount, and a nonce.The agent constructs and cryptographically signs a payment proof for that invoice.
The agent repeats the request with an
X-Payment-Proof header attached.The gateway verifies the proof, settles the payment in ATP on Apostle Chain 7332, and returns the resource with a persisted receipt.
Because there is no checkout page and no session, x402 fits machine-to-machine billing, agent-to-agent commerce, and metered pay-per-request APIs. You can inspect live settlement and receipts on the Apostle Chain explorer, or read the gateway details on the gateway page.
The settlement layer: Apostle Chain 7332 and ATP
Payments settle on the Apostle Chain, whose chain ID is
7332. The native settlement asset is ATP (the
Apostle Token): 18 decimals, Ed25519 signing, native mint authority. ATP can be
mirrored onto other networks — Stellar, Solana, TRON, and XRPL — where the mirrored
units are named aATP ("Apostle-anchored ATP") so they are never
confused with native canonical ATP. Mirrors are claims on locked canonical ATP:
lock-and-mint to issue, burn-and-release to redeem. Full details live on the
ATP page.
Key facts
| Protocol | x402 — agent payments over HTTP 402 (invoice → sign → retry with proof) |
|---|---|
| Settlement chain | Apostle Chain, chain ID 7332 |
| Settlement asset | ATP — 18 decimals, Ed25519; mirrors (aATP) on Stellar, Solana, TRON, XRPL |
| Facilitator API | x402.unykorn.org — /health, /v1/tx, /v1/agent, /v1/airdrop |
| Simulation engine | Genesis Protocol — DOI 10.5281/zenodo.18729652; 44 configurations, 6,820 worlds; crate genesis-multiverse |
| Operator | Kevan Burns — FTH Trading / UnyKorn |
The Genesis Protocol
Alongside the payment rails, the empire publishes the Genesis Protocol,
a deterministic multi-agent simulation engine. Its canonical published run covers
44 experiment configurations across 6,820 worlds and is citable via
DOI 10.5281/zenodo.18729652. The code ships as the Rust crate
genesis-multiverse on crates.io. A signed provenance manifest — with
IPFS-pinned artifacts — is published at
/genesis-provenance.json. It is
used for treasury and resilience stress modeling and agent-population experiments.
Products
The product ladder runs from micro x402 calls (fractions of an ATP) up to enterprise engagements around $75,000. Public rungs include a Wallet Check ($9), Risk Snapshot ($19), Deep Investigation Report ($9.99–$29), Pro Console/Portal ($29–$99/mo), Genesis Pipeline ($197), RWA Scan/ProofPack ($297), RWA Quick Screen ($2,500), RWA Readiness Packet ($7,500), and an Institutional Packet ($25,000). The developer tier on Genesis402 is a Dev API at roughly $49/mo plus 1-ATP simulations. See the full breakdown on the Money playbook.
Frequently asked questions
What is x402 in one sentence?
x402 is a protocol that lets AI agents pay for API requests over the HTTP 402 status code, settling in ATP on Apostle Chain 7332 — no OAuth, no card checkout, and no human in the loop.
What is HTTP 402?
HTTP 402 "Payment Required" is a status code reserved in the HTTP specification but historically unused. x402 activates it: a paid endpoint returns 402 with a machine-readable invoice, and the agent retries with a signed payment proof.
What is ATP and what is Apostle Chain 7332?
ATP (the Apostle Token) is the native settlement asset of the Apostle Chain, whose chain ID is 7332. ATP has 18 decimals, uses Ed25519 signing, and can be mirrored onto Stellar, Solana, TRON, and XRPL as aATP.
How do I register an agent and pay?
Register an agent at the facilitator (x402.unykorn.org, /v1/agent), claim a welcome ATP grant via /v1/airdrop when enabled, then call a paid endpoint. On a 402 response, sign the invoice and retry with the X-Payment-Proof header. Receipts appear in the explorer.
Who operates Genesis402?
Genesis402 is built and operated by Kevan Burns under FTH Trading / UnyKorn. It is real, working infrastructure run primarily by a single operator — not a large venture-funded company.