GraphQL

GraphQL gives clients a precise way to ask for data and gives teams a strongly typed contract for evolving APIs. This course takes you from core concepts to production-minded patterns so you can design, read, and ship GraphQL APIs confidently.

By the end, you should be comfortable with schema design, query and mutation modeling, subscription flows, validation behavior, and runtime resolver execution.

Each topic includes a player. Use it to walk through the content with clear, step-by-step explanations, and feel free to pause anywhere to revisit a section at your own pace.

This course is framework-agnostic and focuses on core GraphQL concepts, so no specific library or framework is required.

Course Path

If you are new to GraphQL, follow the lessons in this order:

• Getting Started
• Type System
• Reading Data
• Writing Data
• Realtime Updates
• Validating Requests
• Field Resolution
• Response Format
• Schema Discovery
• HTTP Transport

What You Will Learn

• How GraphQL differs from REST, and when it is a better fit.
• How the type system (scalars, objects, enums, interfaces, unions, input types) shapes API design.
• How to read and write GraphQL operations with fields, arguments, variables, fragments, and directives.
• How errors, partial data, and response metadata are represented in real responses.
• How subscriptions and transport choices affect real-time architecture and scaling.
• How request validation and resolver execution influence correctness and performance.
• How introspection and schema discovery support tooling and developer experience.

How To Use This Course

• Follow the lessons in order and focus on understanding the examples.
• Revisit Field Resolution, Validating Requests, and HTTP Transport before interviews or production work; these are common weak spots.

Prerequisites

• Basic API knowledge (request/response, status codes, auth).
• Comfort with JSON and backend fundamentals.
• Any programming language is fine; GraphQL concepts are language-agnostic.

Outcome

After this course, you should be able to design a clean schema, implement resolvers correctly, choose transport and execution patterns deliberately, and debug GraphQL behavior with confidence.