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Real-time and historical custom data indexing for any evm chain.

Flair offers reusable indexing primitives (such as fault-tolerant RPC ingestors, custom processors, re-org aware database integrations) to make it easy to receive, transform, store and access your on-chain data.

flair architecture

Why Flair?

Compared to other alternatives the main reasons are:

  • 🚀 Adopting parallel and distributed processing paradigm means high scalability and resiliency for your indexing stack. Instead of constrained sequential processing (e.g Subgraph).
  • 🧩 Focused on primitives, which means on the left you plug-in an RPC and on the right you output the data to any destination database.
  • 🚄 Native real-time stream processing for certain data workload (such as aggregations, rollups) for things like total volume per pool, or total portfolio per user wallet.
  • ☁️ Managed cloud services avoid DevOps and irrelevant engineering costs for dApp developers.
  • 🧑‍💻 Avoid decentralization overhead (consensus, network hops, etc) since we believe to enable best UX for dApps reading data must be as close to the developers as possible.


  • ✅ Listen to any EVM chain with just an RPC URL.
  • Free managed RPC URLs for +8 popular chains already included.
  • Works with both websocket and https-only RPCs.
  • ✅ Track and ingest any contract for any event topic.
  • Auto-track new contracts deployed from factory contracts.
  • Custom processor scripts with Javascript runtime (with Typescript support)
  • Make external API or Webhook calls to third-party or your backend.
  • Get current or historical USD value of any ERC20 token amount of any contract address on any chain.
  • Use any external NPM library.
  • Stream any stored data to your destination database (Postgres, MongoDB, MySQL, Kafka, Elasticsearch, Timescale, etc).

Getting started

1️⃣ Clone the starter boilerplate template and follow the instructions

git clone
# ... follow instructions in


Boilerplate instructions will create a new cluster, generate an API Key, and set up a manifest.yml to index your first contract with sample custom processor scripts.

Learn more about the structure of manifest.yml.

2️⃣ Configure Polygon RPC nodes

Set a unique namespace, Polygon chainId and RPC endpoint in your config. Remember that you can add up to 10 RPC endpoints for resiliency.

  "cluster": "dev",
  "namespace": "my-awesome-polygon-indexing-dev",
  "indexers": [
      "chainId": 137,
      "enabled": true,
      "ingestionFilterGroup": "default",
      "processingFilterGroup": "default",
      "sources": [
        # Highly-recommended to have at least 1 websocket endpoint
        # You can put multiple endpoints for failover

3️⃣ Sync some historical data using backfill command. Remember that enabled: true flag in your config enabled your indexer to capture data in real-time already.

# backfill certain contracts or block ranges
pnpm flair backfill --chain 137 --address
0x06c9823460b76acf26a9af2acfdcac0d03ca6555  -d backward --max-blocks 10000

# backfill for a specific block number, if you have certain events you wanna test with
pnpm flair backfill --chain 137 -b 47807770

# backfill for the recent data in the last X minute
pnpm flair backfill --chain 137 --min-timestamp="30 mins ago" -d backward

4️⃣ Query your custom indexed data.

5️⃣ Stream the data to your own database.


Explore real-world usage of Flair indexing primitives for various use-cases.



Need help?

Our engineers are available to help you at any stage.