A2A Compatible Agent

Index any EVM event,
on any chain

Register any smart contract on any EVM-compatible chain and automatically index historical and real-time events. Query, stream, and deliver via webhooks.

API Reference Agent Card OpenAPI
Google A2A Protocol

Built for AI Agents

evmindexer exposes a standard Agent Card following the Google A2A protocol. Any compatible AI agent can discover capabilities, authentication schemes, and available skills automatically — no manual integration needed.

A2A Agent Card /.well-known/agent.json OpenAPI 3.0 /openapi.json Swagger UI /docs
Exposed Skills

Query Events

Fetch indexed on-chain events by chain, contract, event name, block range, or decoded args. Paginated results with x402 pay-per-use billing.

GET /events x402

Manage Listeners

Register listeners for any contract on any EVM chain. Auto-detects indexed params, backfills history, and switches to real-time WebSocket.

POST /listeners admin

Manage Webhooks

Receive real-time event notifications scoped by chain, contract, event name, or arg values. Batched per block for efficiency.

POST /webhooks admin
Authentication Schemes
Bearer / Admin Secret

Full access. Pass Authorization: Bearer <secret> or X-Admin-Secret.

x402 Pay-per-Use

Event queries billed in USDC on Base. Call GET /events/quote for pricing, then pay and include X-Payment.

Capabilities

What evmindexer does

A single service handles the full lifecycle — from historical backfill to live streaming to webhook delivery.

Any EVM Chain

BSC, Ethereum, Base, Arbitrum — any chain with an EVM-compatible RPC. Configure via environment variables.

Historical + Live Sync

Backfills from a given block via eth_getLogs, then switches to real-time WebSocket subscription with zero gap.

Auto Indexed Param Detection

Automatically detects which event parameters are indexed from on-chain logs at registration time.

Flexible Webhooks

Subscribe by chain, contract, event name, or arg values. All events from a block are batched into one HTTP call.

REST Management API

Create, update, and delete listeners and webhooks at runtime. No restart required. Full Swagger UI at /docs.

x402 Pay-per-Use

Event queries priced per result in USDC on Base. Get a free quote, pay, retrieve data. Admin accounts bypass payment.

REST API

Endpoints

All endpoints are available at https://evmindexer.com. Interactive docs at /docs.

MethodPathDescriptionAuth
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Admin endpoints require Authorization: Bearer <ADMIN_SECRET> or X-Admin-Secret: <secret>. x402 endpoints require a USDC payment on Base — see /events/quote.

Get Started

Quick Start

Register a listener and start receiving events in under a minute.

# Register a listener on BSC
curl -X POST https://evmindexer.com/listeners \
  -H "Authorization: Bearer $ADMIN_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "chain_id": 56,
    "contract_address": "0x...",
    "from_block": 47000000,
    "events": ["Transfer(address indexed from, address indexed to, uint256 value)"],
    "historical_sync": true
  }'

# Get a quote for querying events
curl "https://evmindexer.com/events/quote?chain_id=56&event_name=Transfer&limit=100"

# Fetch events (admin)
curl "https://evmindexer.com/events?chain_id=56&event_name=Transfer&limit=100" \
  -H "Authorization: Bearer $ADMIN_SECRET"