x402
09 agent-services/Coinbase/ACTIVE/aka HTTP 402, x402 Protocol
x402 is Coinbase's open payment protocol — it revives HTTP 402 Payment Required so an agent that hits a paid resource can settle programmatically in stablecoins (USDC on Base) and get the resource, no human checkout step.
What it does
- 01HTTP 402 status as payment handshake
- 02USDC settlement on Base
- 03Client and facilitator SDKs
- 04Middleware for paid endpoints
- 05Open spec with Coinbase backing
Who it's for
API sellers who want machine-payable endpoints, and builders whose agents should buy data, compute, or services without card rails.
Pricing
Open protocol (free); settlement on-chain. List prices as checked against the vendor's pricing page on 2026-09-25; plans change often, so confirm before deciding.
caveat · before you adopt
Crypto rails only — card-network payments are AP2's territory; adoption is early outside the Coinbase ecosystem.
Other agent services (14)
AgentMail
AgentMail · agent-services
Agent Payments Protocol
Google · agent-services
Skyfire
Skyfire · agent-services
Payman
Payman · agent-services
Nevermined
Nevermined · agent-services
AgentCard
AgentCard · agent-services
Keycard
Keycard · agent-services
Arcade
Arcade · agent-services
Scalekit
Scalekit · agent-services
Composio
Composio · agent-services
E2B
E2B · agent-services
Browserbase
Browserbase · agent-services
Exa
Exa · agent-services
Mem0
Mem0 · agent-services
Head-to-head (1)
Frequently asked
What is x402?
x402 is Coinbase's open payment protocol — it revives HTTP 402 Payment Required so an agent that hits a paid resource can settle programmatically in stablecoins (USDC on Base) and get the resource, no human checkout step.
Who is x402 for?
API sellers who want machine-payable endpoints, and builders whose agents should buy data, compute, or services without card rails.
How much does x402 cost?
Open protocol (free); settlement on-chain. List prices as checked against the vendor's pricing page on 2026-09-25; plans change often, so confirm before deciding.
Does x402 run locally or in the cloud?
x402 runs locally on your machine and in the vendor's cloud. Its interfaces are an API or protocol.
What are alternatives to x402?
Other agent service entries in the catalog: AgentMail, Agent Payments Protocol, Skyfire, Payman, Nevermined, AgentCard, Keycard, Arcade, Scalekit, Composio, E2B, Browserbase, Exa, Mem0. Different categories solve the same problem differently — see the Agent services category page for tradeoffs.
What should I know before adopting x402?
Crypto rails only — card-network payments are AP2's territory; adoption is early outside the Coinbase ecosystem.