P402.io

What is P402.io

P402.io provides a routing control plane for reliable x402 crypto micropayments on the Base blockchain, enabling paid APIs for agents.

How to use P402.io

1. Return 402 Payment Required: Respond to unpaid requests with the standard 402 status and price headers.
2. Client Signs the Challenge: The client wallet signs the payment request (EIP-712) and retries.
3. Router Verifies & Settles: P402 verifies the signature, ensures funds, and settles the transaction on-chain.

Features of P402.io

• Dynamic Routing: Selects the best path for every request, tracking provider health and speed in real-time.
• Global Spend Caps: Enforces strict limits for every agent and route.
• Auto-Discovery: Automatically lists services on the Bazaar with up-to-date metadata.
• Cost Intelligence: Tracks every penny from request to settlement, providing reasons for failed calls.
• Intent-Based Routing: Routes requests based on cost, speed, or quality, with semantic caching.
• Policy Enforcement: Cryptographically enforces budgets and access rules.
• Decision Tracing: Provides full observability into payment decisions and settlement events.
• Replay Safety: Implements idempotency controls to reduce duplicate settles and noisy retries.
• Role-based access: For admin actions, key rotation, least-privilege secrets, and audit logs.

Use Cases of P402.io

• Pay-per-call APIs: Meter every request without subscriptions.
• MCP servers: Charge per tool invocation.
• Agent-to-agent: Policies gate spend and domains.
• Internal chargeback: Facilitates paid edges between services across teams.
• Self-Healing Data Pipelines: Agents automatically switch to premium access via P402 challenges when hitting rate limits.
• Autonomous Swap Research: Agents purchase high-fidelity intelligence on-demand to validate trades.

Pricing

P402.io charges a 1% fee on settled transactions.

FAQ

• I still get 402 after attaching the payment header. Why?
  1. Use PAYMENT-SIGNATURE, not legacy X-PAYMENT.
  2. Signature could be invalid.
  3. Amount too low.
  4. Address lacks USDC or KYT flagged.
• What does Bazaar do? Bazaar lists payable endpoints using machine-readable metadata, enabling developers and agents to discover pricing and routes.
• Do different facilitators exist? Yes. The ecosystem lists multiple facilitators with different network, token, and feature profiles.
• What changes in v2 matter for Router? V2 adds lifecycle hooks for custom logic at key points in the flow, plus an extension system for discovery.