Pay Any API.
Any Agent.
The premier smart escrow payment protocol on Solana. Empower your LLMs to autonomously negotiate and pay invoices on-chain via simple HTTP 402.
A Living Network of Autonomous Agents.
Watch LLMs negotiate, settle, and trade value in real-time across the globe. X402 provides the cryptographic rails for machine-to-machine commerce without intermediaries.
- Deterministic latency under 400ms globally.
- 100% on-chain cryptographic settlement.
- Permissionless agent identity verification.
The HTTP 402 Standard, Reimagined.
Seamless flow from inference request to cryptographic settlement.
1. AI Inference
LLM makes HTTP request to your premium API endpoint.
2. HTTP 402 Required
Server returns HTTP 402 with Solana Escrow PDA requirements.
3. Smart Settlement
Agent pays invoice on-chain. Funds unlock upon successful service.
Integrate with Two Lines of Code.
Inject the `@tx4/agentid` toolkit directly into your Langchain, Eliza, or Vercel AI SDK instances. Your agents will automatically handle `402 Payment Required` errors, fund the escrow on Solana, and retry the request completely autonomously.
- Vercel AI SDK Support
- Langchain & Langgraph
- Eliza Framework
- Raw HTTP Client for Rust/Go
Continuous Volume Decay Pricing.
First $15 in volume is 100% Free. After that, fees decay from 2% down to 0.1% as you grow. Mathematically enforced on-chain. No negotiation required.
Simulate Your Volume
First $15 is 100% Free! Drag the slider to see how your protocol fee decays from 2.0% as you scale.
Zero Counterparty Risk
Funds are cryptographically locked in a programmatic vault. If the API fails to deliver, an automated 60-second refund is issued directly back to the payer.
Native MCP Integration
Plug-and-play Model Context Protocol (MCP) packages available for Vercel AI SDK, Langchain, and Eliza. Your AI agents pay on their own.
Instant Settlement
Leverage Solana's sub-second finality. Tiered basis point fee structures mathematically verified via Anchor smart contracts with 100% test coverage.