# Flair

## 🔮 Flair <a href="#user-content--flair" id="user-content--flair"></a>

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

[Flair](https://docs.flair.dev/) 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.

<figure><img src="https://1786307500-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqXsIo4b4WtOTfICyOIxa%2Fuploads%2Fgit-blob-0263d4f2fc638608e77ebb6e023f188930a20e2c%2F68747470733a2f2f696d6775722e636f6d2f30713562485a4b2e706e67.png?alt=media" alt=""><figcaption></figcaption></figure>

### Why Flair? <a href="#user-content-why-flair" id="user-content-why-flair"></a>

Compared to other alternatives the main reasons why are:

* 🚀 Adopting **parallel and distributed processing** paradigm means high scalability and resiliency for your indexing stack. Instead of constrained sequential processing (e.g Subgraph).
* 🧩 Work out-of-box with **any EVM chain**, you plug-in an RPC and indexer starts.
* 🚄 Native **real-time stream processing** for certain data workload (such as aggregations, rollups) for things like total volume per pool.
* **☁️ Managed** cloud services avoid DevOps and irrelevant engineering costs for dApp developers.

{% embed url="<https://youtu.be/rUczQjRnDaM>" %}

#### Features <a href="#features" id="features"></a>

* ✅ 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, MognoDB, Kafka, Elasticsearch, Timescale, etc)

### Getting Started <a href="#user-content-getting-started" id="user-content-getting-started"></a>

1️⃣ Clone the [starter boilerplate](https://github.com/flair-sdk/starter-boilerplate) template and follow the instructions

```
git clone https://github.com/flair-sdk/starter-boilerplate.git
# ... follow instructions in README.md
```

{% hint style="info" %}
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](https://docs.flair.dev/reference/manifest.yml).
{% endhint %}

2️⃣ Configure Cronos RPC nodes

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

```
{
  "cluster": "dev",
  "namespace": "my-awesome-cronos-indexing-dev",
  "indexers": [
    {
      "chainId": 25,
      "enabled": true,
      "ingestionFilterGroup": "default",
      "processingFilterGroup": "default",
      "sources": [
        # Highly-recommended to have at least 1 websocket endpoint
        "wss://XXX",
        # You can put multiple endpoints for failover
        "https://evm.cronos.org"
      ]
    }
  ]
}
```

3️⃣ Sync some historical data using [backfill command](https://docs.flair.dev/reference/backfilling). 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 25 --address 0x6911dE03899e040745bdAC855333E294B927945D -d backward --max-blocks 10000

# backfill for a specific block number, if you have certain events you wanna test with
pnpm flair backfill --chain 25 -b 10329277

# backfill for the recent data in the last X minute
pnpm flair backfill --chain 25 --min-timestamp="30 mins ago" -d backward
```

4️⃣ [Query](https://docs.flair.dev/#getting-started) your custom indexed data.

5️⃣ Stream the data to your [own database](https://docs.flair.dev/reference/database#your-own-database).

### Examples <a href="#user-content-examples" id="user-content-examples"></a>

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

#### DeFi <a href="#user-content-defi" id="user-content-defi"></a>

* [Aggregate protocol fees in USD across multiple chains](https://github.com/flair-sdk/examples/tree/main/aggregate-protocol-fees-in-usd)
* [Calculate "Health Factor" of positions with contract factory tracking](https://github.com/flair-sdk/examples/tree/main/health-factor-with-factory-tracking)
* [Index Uniswap v2 swaps with USD price for all addresses](https://github.com/flair-sdk/examples/tree/main/uniswap-v2-events-from-all-contracts-with-usd-price)

#### NFT <a href="#user-content-nft" id="user-content-nft"></a>

* [Index ERC721 and ERC1155 NFTs on any EVM chain with an RPC URL](https://github.com/flair-sdk/examples/tree/main/erc721-and-erc1155-nft-indexing)

### Need help? <a href="#user-content-need-help" id="user-content-need-help"></a>

[Our engineers](https://docs.flair.dev/talk-to-an-engineer) are available to help you at any stage.