> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sqd.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Packages overview

> The Squid SDK packages used in a Substrate squid and what each one does.

Squid SDK is modular: a squid combines a chain-specific data source, a store, and optional
code-generation and serving tools. This page lists the packages relevant to Substrate
squids.

## Data source

* [`@subsquid/substrate-processor`](./substrate-processor/general) — `SubstrateBatchProcessor`,
  the Substrate data source and runner

## Typegen and Substrate utilities

* [`@subsquid/substrate-typegen`](../guides/substrate/data-sourcing-miniguide) — runtime-aware
  pallet data decoding and storage queries
* `@subsquid/ink-typegen` — decoders for [ink! contracts](../examples-tutorials/ink)
* `@subsquid/ss58` — SS58 address encoding/decoding
* [`@subsquid/frontier`](./frontier) — Frontier EVM pallet data extraction

## Stores

Any store works with any data source:

* [`@subsquid/typeorm-store`](./data-stores/typeorm-store) — PostgreSQL, with
  [`@subsquid/typeorm-codegen`](./typeorm-codegen) (dev dependency) and
  [`@subsquid/typeorm-migration`](./typeorm-migration)
* [`@subsquid/file-store`](./data-stores/file-store) — filesystem datasets (CSV, JSON, Parquet,
  local or S3)
* [`@subsquid/bigquery-store`](./data-stores/bigquery-store) — Google BigQuery

The store contract itself is documented in [Store interface](./data-stores/store-interface).

## Serving and tooling

* [`@subsquid/graphql-server`](./openreader/overview) — the OpenReader GraphQL server, derived
  from the [schema file](./schema-files/schema-files-codegen)
* [Hasura configuration tool](./hasura-configuration) — for Hasura-based APIs
* [`@subsquid/logger`](./logger) — structured logging
* [Squid CLI](/en/cloud/reference/cli/installation) — scaffolding
  ([`sqd init`](./create-squid)), command runner, and SQD Cloud deployment