What is GraphQL? Flexible Queries for Modern APIs
GraphQL is a query language for APIs and a runtime for executing those queries. Unlike REST, clients specify exactly what data they need. Learn how GraphQL works, its trade-offs versus REST, and where it fits in enterprise integrations.
What is GraphQL?
GraphQL is a query language for APIs developed by Meta and released as open source in 2015. Instead of multiple fixed REST endpoints returning predefined shapes, a GraphQL API exposes a single endpoint and lets clients declare precisely what data they want in a query — no more, no less. This eliminates over-fetching (receiving more data than needed) and under-fetching (making multiple requests to assemble one logical result).
- Single endpoint; clients specify the exact fields they want
- Eliminates over-fetching and under-fetching
- Strongly typed schema defines all available data and operations
- Supports queries (read), mutations (write), and subscriptions (real-time)
- Used by GitHub, Shopify, Twitter/X, and thousands of enterprise APIs
How GraphQL Works
The server defines a strongly typed schema describing all available types, fields, and operations. Clients send a query document specifying the fields they need — nested as deep as the schema allows. The server resolves each field and returns exactly the requested shape as JSON.
Define the schema
The server declares all available types (User, Order, Product), their fields, and the root Query/Mutation types. The schema is the contract.
Client writes a query
The client writes a query specifying exactly which fields to return — including nested relationships — in a single request: query { user(id: '1') { name, email, orders { total } } }
Resolver execution
The GraphQL runtime calls resolver functions for each requested field. Resolvers fetch data from databases, REST APIs, or other sources and compose the result.
Typed JSON response
The server returns a JSON object matching the query shape exactly — only the requested fields, no more, no less.
Common GraphQL Use Cases
Mobile and frontend apps
Mobile apps request only the fields needed for a screen — reducing payload size and battery usage compared to fixed REST endpoints.
API aggregation layer
A GraphQL gateway aggregates multiple microservices — user service, billing service, product catalog — into a single queryable graph, simplifying frontend development.
Developer portals and tooling
GitHub's GraphQL API lets developers build precisely targeted integrations — fetching only the repository data relevant to their automation, not full REST payloads.
GraphQL in FlowGenX AI
FlowGenX supports GraphQL connectors in Integration Studio alongside REST. You can define GraphQL queries and mutations as reusable workflow actions, and your AI agents can invoke them just like any REST tool. GraphQL subscriptions can also trigger FlowGenX workflows via the webhook listener, enabling real-time event-driven automation on GraphQL-backed SaaS platforms.
Frequently Asked Questions
See It In FlowGenX
Related Terms