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Core API Introduction

At the moment, Squid SDK GraphQL server can only be used with squids that use PostgreSQL as their target database.
GraphQL is an API query language, and a server-side runtime for executing queries using a custom type system. Head over to the official documentation website for more info. A GraphQL API served by the GraphQL server has two components:
  1. Core API is defined by the schema file.
  2. Extensions added via custom resolvers.
In this section we cover the core GraphQL API, with short explanations on how to perform GraphQL queries, how to paginate and sort results. This functionality is supported via OpenReader, SQD’s own implementation of OpenCRUD.

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Available for both EVM and Substrate

The OpenReader GraphQL server works with any squid that stores data in PostgreSQL, regardless of whether you’re indexing EVM or Substrate chains. The schema file defines your data model, and OpenReader automatically generates the GraphQL API based on that schema.

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Next steps

Queries

Learn how to query your data

Filters

Filter results with AND/OR conditions

Sorting

Sort query results

Pagination

Paginate large result sets