402 Index
The paid API directory for AI agents — indexed, verified, and searchable
Ecosystem Overview
Agent Discovery
Search the directory like an AI agent would through the MCP server
{
"tool": "search_services",
"arguments": {}
}
Start typing or adjust filters to search...
Live Endpoint Health Check
Paste any API URL to run a real-time health check — see the protocol handshake live
Payment Flow
How an agent pays for an API call — step by step
Agent Sends Request
Agent discovers endpoint via 402index and sends request
GET https://llm402.ai/v1/chat/completions
Server Returns 402
Server requires payment — returns 402 with payment instructions
WWW-Authenticate: L402 macaroon="AGIAJEem...", invoice="lnbc21n1..."
Agent Pays Invoice
Agent pays Lightning invoice automatically via lnget or wallet
Lightning BOLT11 invoice Amount: 21 sats Expiry: 60 seconds
Agent Retries with Token
Agent retries request with proof of payment
Authorization: L402 <macaroon>:<preimage>
Server Returns 200
Server validates payment and returns the requested data
HTTP/1.1 200 OK
Content-Type: application/json
{ "data": "..." }