> ## Documentation Index
> Fetch the complete documentation index at: https://sequence-0fb8d9e6-api_docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Indexer Overview

> Real-time balances, transfers, NFTs, prices, and contract events across EVM chains with webhooks and subscriptions. Use it as your production read layer for onchain apps.

**Indexer** gives you low-latency reads across EVM chains: balances and portfolio, token and NFT ownership, transfers and logs, prices, and contract events. It is built for production: cursor-based pagination, filters, webhooks, and event subscriptions. All in a scalable, 99.99% uptime service.

<CardGroup>
  <Card title="API Reference" href="/api-references/indexer/overview">
    Endpoints, filters, pagination, and response shapes.
  </Card>

  <Card title="Cross-Chain Token Balances" href="/solutions/indexer/cross-chain-balances">
    Fetch token balances across multiple EVM chains with a single API call.
  </Card>

  <Card title="Token Balances" href="/solutions/indexer/token-balances">
    Fetch token balances for any wallet or contract address.
  </Card>

  <Card title="Transaction History" href="/solutions/indexer/transaction-history">
    Fetch transaction history for any wallet or contract address.
  </Card>

  <Card title="Subscriptions" href="/solutions/indexer/subscriptions">
    Subscribe to events, receipts, balance updates for any wallet or contract address.
  </Card>

  <Card title="Webhooks" href="/solutions/indexer/webhooks">
    Receive webhook triggers for any contract emitted event.
  </Card>
</CardGroup>

## What you can build

* **Wallet and portfolio views**: unified balances and positions across chains.
* **Activity feeds**: transfers, mints, burns, sales.
* **Collection browsers**: NFTs with metadata and ownership.
* **Analytics**: prices, volumes, holders, and contract events.

## Quickstart

Use the SDKs for the fastest path, or call the REST API directly. The examples below illustrate typical requests; see the API reference for exact parameters and response fields.

<CodeGroup>
  ```shell Curl theme={null}
  curl -X POST https://polygon-indexer.sequence.app/rpc/Indexer/GetTokenBalances \
   -H "Content-Type: application/json" \
   -H "X-Access-Key: AQAAAAAAAF_JvPALhBthL7VGn6jV0YDqaFY" \
   -d '{ "accountAddress": "0x8e3E38fe7367dd3b52D1e281E4e8400447C8d8B9", "includeMetadata": true }'
  ```

  ```ts Typescript theme={null}
  // Make sure to install the @0xsequence/indexer package:
  // npm install @0xsequence/indexer
  // or
  // yarn add @0xsequence/indexer

  import { SequenceIndexer } from '@0xsequence/indexer'

  const indexer = new SequenceIndexer('https://polygon-indexer.sequence.app', 'AQAAAAAAAF_JvPALhBthL7VGn6jV0YDqaFY')

  // try any account address you'd like :)
  const accountAddress = '0xabc...'

  // query Sequence Indexer for all token balances of the account on Polygon
  const tokenBalances = await indexer.getTokenBalances({
  	accountAddress: accountAddress,
  	includeMetadata: true
  })
  console.log('tokens in your account:', tokenBalances)
  ```

  ```go Go theme={null}
  import (
  	"context"
  	"fmt"
  	"log"
  	"net/http"

  	"github.com/0xsequence/go-sequence/indexer"
  )

  func GetTokenBalances(accountAddress string) {
  	seqIndexer := indexer.NewIndexer("https://polygon-indexer.sequence.app", "AQAAAAAAAF_JvPALhBthL7VGn6jV0YDqaFY")

  	includeMetadata := true

  	tokenBalances, _, err := seqIndexer.GetTokenBalances(context.Background(), &accountAddress, nil, &includeMetadata, nil, nil)
  	if err != nil {
  		log.Fatal(err)
  	}
  	fmt.Println("tokenBalances:", tokenBalances)
  }
  ```
</CodeGroup>

## Supported Networks

You can see the [full list of supported networks here](https://status.sequence.info).

## Further Reading

Here are a few example queries you can make to a blockchain from your app, game, or wallet:

* [Fetch all tokens & NFTS in a wallet across all EVMs](/solutions/indexer/cross-chain-balances)
* [Fetch all tokens & NFTS in any wallet including all metadata](/solutions/indexer/token-balances)
* [Fetch the transaction history for any wallet address](/solutions/indexer/transaction-history)
* [Fetch all unique tokens in a particular ERC20/721/1155 contract, including total supplies](/solutions/indexer/token-balances)
* [Fetch the transaction history for any token contract address](/solutions/indexer/transaction-history)
* [Listen to transactions for particular tokens/contracts/addresses via webhooks](/solutions/indexer/webhooks)
* [Subscribe to events, receipts, balance updates for any wallet or contract address](/solutions/indexer/subscriptions)