> ## Documentation Index > Fetch the complete documentation index at: https://bruno-a6972042-mintlify-ws-multi-message-1777871287.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Overview Bruno can send requests using GraphQL, an open-source query language and runtime for APIs. Each GraphQL request has a URL (the data endpoint) and a query (defining the data to retrieve or modify). ## GraphQL request interface GraphQL APIs let clients request only the data they need through a single endpoint. It’s schema-driven, allowing clients to introspect and avoid overfetching or underfetching data. **Query builder** is also supported to help you build your queries easily. gql-interface The API schema defines available fields, and the request may include authentication, headers, and settings as needed. GraphQL requests support three operations: * **Query**: Retrieves data, specifying fields and optional arguments for precise results. * **Mutation**: Modifies data (create, update, delete), with specified fields returned after the operation. * **Subscription**: Provides real-time updates by listening for changes to specific data fields over a persistent connection. 1. [GraphQL API](./graphql-api) 2. [GraphQL Variables](./graphql-variables)