---
title: Indexers
description: Discover blockchain indexers. Enhance data access, enable fast and complex queries, and optimize blockchain data for seamless app performance.
categories:
- Tooling
- Parachains
url: https://docs.polkadot.com/parachains/integrations/indexers/
word_count: 295
token_estimate: 410
version_hash: sha256:5ab02e49d6c91e066fd55f466b965e8cdcf7bc3f41cf9d89058e26b6cdc9a2ec
last_updated: '2026-06-04T16:08:37+00:00'
---

# Indexers

## The Challenge of Blockchain Data Access

Blockchain data is inherently sequential and distributed, with information stored chronologically across numerous blocks. While retrieving data from a single block through JSON-RPC API calls is straightforward, more complex queries that span multiple blocks present significant challenges:

- Data is scattered and unorganized across the blockchain.
- Retrieving large datasets can take days or weeks to sync.
- Complex operations (like aggregations, averages, or cross-chain queries) require additional processing.
- Direct blockchain queries can impact dApp performance and responsiveness.

## What is a Blockchain Indexer?

A blockchain indexer is a specialized infrastructure tool that processes, organizes, and stores blockchain data in an optimized format for efficient querying. Think of it as a search engine for blockchain data that:

- Continuously monitors the blockchain for new blocks and transactions.
- Processes and categorizes this data according to predefined schemas.
- Stores the processed data in an easily queryable database.
- Provides efficient APIs (typically [GraphQL](https://graphql.org/)) for data retrieval.

## Indexer Implementations

<div class="grid cards" markdown>

-   __Subsquid__

    ---

    Subsquid is a data network that allows rapid and cost-efficient retrieval of blockchain data from 100+ chains using Subsquid's decentralized data lake and open-source SDK. In simple terms, Subsquid can be considered an ETL (extract, transform, and load) tool with a GraphQL server included. It enables comprehensive filtering, pagination, and even full-text search capabilities. Subsquid has native and full support for EVM and Substrate data, even within the same project.

    [:octicons-arrow-right-24: Reference](https://sqd.dev/)

-   __Subquery__

    ---

    SubQuery is a fast, flexible, and reliable open-source data decentralised infrastructure network that provides both RPC and indexed data to consumers worldwide.
    It provides custom APIs for your web3 project across multiple supported chains.

    [:octicons-arrow-right-24: Reference](https://subquery.network/)

</div>