Open Standard · Linux Foundation

HTTP has a payment code.
Now it works.

x402 turns 402 Payment Required into a real protocol. AI agents discover services, pay in USDC, and get results — no API keys, no accounts, no humans in the loop.

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Three exchanges. Zero friction.

No signup. No dashboard. No API key rotation.

1

Request

Send a normal HTTP request. No auth headers.

agent → server 
POST /api/v1/explain-code
Content-Type: application/json

{"code": "def fib(n): ..."}
→
2

402 + Price

Server returns the exact price. Agent reads it.

server → agent 
HTTP/1.1 402 Payment Required
PAYMENT-REQUIRED: <base64>

# Decoded:
# amount: 50000 (USDC micro)
# network: eip155:8453 (Base)
→
3

Pay + Result

Agent signs USDC transfer. Server verifies and responds.

agent → server → agent 
POST /api/v1/explain-code
PAYMENT-SIGNATURE: <base64>

HTTP/1.1 200 OK
PAYMENT-RESPONSE: <base64>
{"result": "This function..."}

API keys don't scale to agents.

x402 is how machine-to-machine commerce actually works.

🔑

No credentials to manage

The payment receipt is the credential. An agent with a USDC balance can call any x402 service in the world without a single API key.

🤖

Built for autonomous agents

Agents discover services, evaluate prices, and pay — all without human intervention. The protocol was designed for this. OAuth wasn't.

⛓

Every payment on-chain

Settled in USDC on Base L2. Instant, auditable, final. No chargebacks, no billing disputes, no monthly invoices.

📡

Discovery built in

Any x402 service exposes /.well-known/x402.json — a machine-readable manifest of what it does, what it costs, and where to pay.

Open Standard

Backed by the Linux Foundation

x402 is a vendor-neutral open standard with 50+ member organizations. Not a startup's proprietary protocol — shared infrastructure for the future of machine commerce.

Coinbase Cloudflare Stripe Visa AWS Adyen Shopify 50+ members
75M+
Transactions / 30 days
$24M+
Volume / 30 days
26,000+
Live services
Base L2
Primary network

Where 24K Labs fits

We don't own the protocol. We build what runs on it.

Layer 1

The Protocol

x402 spec, facilitators, SDKs. Owned by the Linux Foundation. We use it, we don't build it.

Linux Foundation · Coinbase · Cloudflare
Layer 2

Discovery & Authority

Gold-402 directory. 26,000+ services. The editorial layer that tells agents what's worth using.

24K Labs ← We are here
Layer 3

Services

The AI tools agents actually pay for. Code analysis, time context, and more. Also 24K Labs.

24K Labs · 26,000+ others

Start building on x402.

Use our services, list in our directory, or build your own x402 endpoint.

Quickstart Guide Browse Directory Our Services