JSON Guides & Tutorials
Learn everything about JSON: from basics to advanced topics. Each guide includes practical examples you can try with our free tools.
Six guides, written against the tools on this site. When a guide states what a parser does with a trailing comma or how much gzip saves on a minified payload, that number came from running it, not from another article.
They are meant to be read in order if JSON is new to you, or dipped into when you hit a specific problem. Each one ends with the tools that apply to it.
Where to start
If you are learning the format, read What is JSON, then Common Syntax Errors. Together they cover the structure and the mistakes that structure invites.
If you already ship JSON and are choosing between formats or designing an API, start with JSON vs YAML vs XML and JSON in REST APIs. Add JSON Schema when you need the shape enforced rather than documented.
If your files stopped fitting in memory, go straight to Working with Large JSON Files. It is the only guide here that assumes the naive approach has already failed.
What is JSON? A Complete Beginner's Guide
Learn what JSON is, its syntax, data types, and why it became the web's standard data format.
Covers- Objects, arrays, and the six value types
- Why the format won over its alternatives
- Day-to-day habits that prevent breakage later
Common JSON Syntax Errors and How to Fix Them
Fix the most common JSON errors: trailing commas, single quotes, comments, and more.
Covers- Trailing commas, single quotes, unquoted keys
- Why comments are rejected and what to do instead
- Locating the exact character a parser choked on
JSON vs YAML vs XML: When to Use Which
Compare JSON, YAML, and XML. Understand when to use each format and how to convert between them.
Covers- A side-by-side comparison of the three formats
- What each format is actually good at
- Choosing one for config, for the wire, for documents
How to Use JSON in REST APIs
Master JSON in REST APIs: request/response formats, headers, status codes, and best practices.
Covers- Content-Type, Accept, and request bodies
- Response envelopes, error shapes, status codes
- Response designs that survive their second version
JSON Schema: Validate Your Data Structure
Validate your JSON data with JSON Schema. Learn types, required fields, and constraints.
Covers- types, required, and the constraint keywords
- A worked registration payload, validated
- Where a schema beats a TypeScript interface
Working with Large JSON Files: Tips and Best Practices
Strategies for handling large JSON files efficiently. Performance tips and alternative formats.
Covers- What actually breaks first as size grows
- Minifying, streaming, splitting, and NDJSON
- The point where a browser tool is the wrong tool