Build Your Own Blockchain Indexer Using Our Framework

Install. Describe your model. Run your indexer in minutes.
Self-hosted, cost-effective, and feels like regular backend development.

Works on

index.ts· Your complete blockchain indexer

import { bootstrap, compileStateModelBTC } from '@easylayer/bitcoin-crawler';

export const AddressUtxoWatcherModel = {
  modelId: 'wallet-utxo-watcher',
  state: { wallets: new Set(['1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa']), utxos: new Map() },
  sources: {
    async vout(ctx) { return { a: ctx.vout.scriptPubKey.addresses?.[0], k: `${ctx.tx.txid}:${ctx.vout.n}`, v: toSat(ctx.vout.value) }; },
    async vin(ctx) { return { k: `${ctx.vin.txid}:${ctx.vin.vout}` }; },
    async block(ctx) { ctx.applyEvent('Deposit', ctx.block.height, { o: ctx.locals.vout, i: ctx.locals.vin }); },
  },
  reducers: {
    Deposit(s, e) {
      const { o = [], i = [] } = e.payload || {};
      for (const x of o) (s.utxos.get(x.a) || s.utxos.set(x.a, new Map()).get(x.a)).set(x.k, x.v);
      for (const y of i)
        for (const [a, bag] of s.utxos)
          if (bag.delete(y.k) && !bag.size) s.utxos.delete(a);
    },
  },
};

Custom Data Models: Describe what blockchain data you need—wallet balances, fees, specific addresses. Store only relevant data, not the entire blockchain. Simple declarative or class-based syntax.
Learn more about Custom Data Models
Network Providers: Just 2 RPC requests per block for Bitcoin. Connect to your node or external providers like QuickNode. Multiple strategies: RPC pulling, P2P, ZMQ subscriptions with automatic failover.
Learn more about Network Providers
Mempool Monitoring: Track unconfirmed transactions in real time before they hit blocks. Built-in mempool model or integrate into custom models. Essential for payment processors and wallets.
Learn more about Mempool Monitoring
API & Transports: Built-in APIs over HTTP, WebSocket, IPC, Electron, and browser. Real-time event streams and request–response queries. Use the Transport SDK for easy client integration.
Learn more about API & Transports
Event Store & Databases: Event Sourcing with automatic reorg handling. Choose SQLite for development, PostgreSQL for production, or IndexedDB for browser. Your infra, your data, auto-managed schema.
Learn more about Event Store & Databases
System Models: Built-in models for chain validation and mempool monitoring work out of the box. Subscribe to their events immediately. Network integrity checks with Merkle proofs (configurable).
Learn more about System Models

How does it work? 🧐

Install crawler package and describe your custom Model - what blockchain data you need to track. Configure blockchain Node Provider (your self node or external like QuickNode) and Event Store (SQLite,PostgreSQL or IndexDB). That's it - framework handles everything else.

Your model parses blocks and generates domain events. Framework stores them with Event Sourcing pattern, automatically handles blockchain reorgs, and exposes Transport APIs (HTTP, WebSocket, IPC) for queries and real-time event streams.