Functional Testing of GraphQL APIs: Simple Checks That Catch Real Bugs

In this talk, I will share simple and practical ways to test GraphQL APIs using tools like opensource (Altair)/Postman. The focus will be on real testing scenarios that help catch actual bugs.

I will cover how to test positive and negative cases, validate query inputs, and check how APIs behave with wrong or missing data. I will also explain how to test GraphQL-specific concepts like cost parameters (cost, height, depth) to avoid heavy queries.

Another important part is datatype validation—how to verify nullable and non-nullable fields, and ensure correct data mapping in responses.

This session is based on real testing experience and will focus on simple steps that testers and developers can apply directly in their projects.