JSON Guides & Tutorials
Free, practical guides to help you understand, write, debug and master JSON — from absolute basics to common gotchas.
Each guide is checked against primary specifications or official runtime documentation, includes examples tested with the current editor, and carries a publication or revision date. Read our editorial and testing method.
What Is JSON? A Beginner’s Guide
JSON is the most widely used data format on the web. This guide explains what it is, how it is structured, and where you will run into it as a developer.
JSON Syntax Rules Explained (With Examples)
JSON has a small but strict grammar. This reference walks through every rule with valid and invalid examples so your data parses the first time.
Common JSON Errors and How to Fix Them
Every developer hits "Unexpected token in JSON" eventually. Here are the most common JSON errors, what causes them, and exactly how to fix each one.
JSON vs XML vs YAML: A Practical Comparison
JSON, XML and YAML all store structured data, but each suits different jobs. See the same data in all three and learn when to reach for which.
How to Format and Validate JSON Online
Turn messy, minified JSON into clean readable output and catch errors instantly. A step-by-step walkthrough of formatting and validating JSON online.
Escaping and Stringifying JSON Explained
Escaping and stringifying trip up a lot of developers. Here is what each operation does, when you need it, and how to do it with clear examples.
JSON Schema: Validating the Shape of Your Data
JSON tells you the data is well-formed; JSON Schema tells you it is correct. Learn to describe and validate the shape of your JSON with a reusable schema.
Querying JSON with JSONPath
When a JSON response is big and deeply nested, JSONPath lets you pull out exactly the values you want with a compact expression. Here is the full syntax.
How to Work With Large JSON Files
A 2GB JSON file will crash a naive parser. Learn the techniques — streaming, NDJSON, jq and chunking — that let you process huge JSON without exhausting memory.
Parsing JSON in JavaScript and Python
A side-by-side guide to reading and writing JSON in the two most common languages, including error handling, dates, and the gotchas that bite people.
How to Compare Two JSON or API Responses
Two API responses that should be identical often differ in ways that are hard to spot by eye. Here is a reliable workflow for diffing JSON and reading the result.
Converting JSON to CSV (and Back) Without Losing Data
CSV is where spreadsheets live and JSON is where apps live. Converting between them is easy until nested objects, commas and leading zeros get involved.
Generating Types and Code From a JSON Sample
Hand-writing model classes to match an API is tedious and error-prone. Generating them from a real JSON sample is faster — if you understand how inference works.
A Practical jq Cookbook
jq is the Swiss-army knife for JSON on the command line. Here are the recipes that cover most day-to-day tasks, each ready to copy, paste and adapt.
Transforming JSON With JSONata
Where JSONPath only selects, JSONata transforms. Learn how to filter, aggregate and build entirely new JSON shapes with this concise expression language.
Safely Sharing JSON: Redacting Sensitive Data
That API response you are about to paste into a bug report probably contains more than you think. Here is how to find and redact secrets before you share JSON.
Understanding JSON Web Tokens (JWT)
JWTs are everywhere in modern auth, but they are widely misunderstood. Here is how they are built, what the claims mean, and the mistakes that cause breaches.