JSON
JSON has the odd distinction of being simple enough to learn in ten minutes and strict enough to reject your file for a reason you cannot see. Most of the time it just works; the rest of the time you are staring at "Unexpected token } in JSON at position 412" wondering which of four hundred lines is at fault.
This cluster covers both halves. The format itself — its six value types, the handful of grammar rules, and the parts of the specification that surprise people who have used it for years. And the failure modes: what each parser error actually means, why a payload that works in JavaScript is rejected as JSON, and what happens to a sixteen-digit number on its way through.
ToolForge has a dozen tools in this area, and the guides here sit alongside them rather than duplicating them. Where a tool page explains how to operate the widget, these explain the format underneath it — with the specification cited, because JSON is one of the few subjects where the primary sources are short, free and worth reading.
Start with the guide
GuideWhat Is JSON?
JSON is a text format for structured data, with six value types and a grammar you can read in an afternoon. What it is, where it came from, and where it bites.
Tools for this
The tools these guides refer to, most relevant first.
JSON Formatter
Format, validate, and beautify JSON online
JSON Parse Tool
Parse JSON strings into JavaScript objects
JSON Escape / Unescape
Escape and unescape JSON strings
JSON Diff Comparator
Compare two JSON files and find differences
JSON Path Finder
Find and extract values from JSON using JSONPath
YAML ↔ JSON Converter
Bidirectional YAML and JSON conversion with error reporting
XML to JSON Converter
Parse XML strings to clean JSON objects in your browser
JSON to CSV Converter
Convert JSON data to CSV format
Guides & tutorials
How to Format JSON
Turn minified JSON into something readable, or the reverse. What formatting changes about your data, what it silently normalises, and when to minify.
How to Validate JSON
Validating JSON answers three different questions: is it well-formed, does it match a schema, and is the data right. How to check each, and where each stops.
How to Escape Strings in JSON
Escaping JSON is easy until there are layers. How to escape a string, how to nest JSON inside JSON, and how to get a payload through a shell intact.
Comparisons
JSON vs XML: Which Should You Use?
JSON is smaller and easier to parse; XML carries attributes, namespaces and real validation. Where each one wins, and why the choice is rarely close any more.
JSON vs YAML: What Is the Difference?
YAML is JSON with comments, less punctuation and more ways to shoot yourself. What differs, why config chose YAML, and the traps in converting between them.
Troubleshooting
Reference
Frequently asked questions
Is JSON a programming language?
No. It is a data format — a set of rules for writing structured values as text. The name comes from JavaScript, whose object syntax it borrowed, but it defines no behaviour, no variables and no logic. ECMA-404 is explicit that it specifies syntax only and deliberately says nothing about what the data means.
Why does JSON not allow comments?
Because the grammar has no production for them, and a conforming parser must reject anything the grammar does not permit — ECMA-404 defines the syntax exhaustively and comments are simply not in it. The omission is deliberate rather than an oversight. Formats that do allow comments, such as JSON5, JSONC and YAML, are separate formats even where they look similar.
Do JSON keys have to be in a particular order?
No, and you cannot rely on order being preserved either. RFC 8259 notes that parsing libraries differ over whether they expose the ordering of object members at all. Treat an object as an unordered bag of named values; if sequence matters, use an array.
Is JSON secure to paste into an online tool?
It depends entirely on the tool. Every JSON tool on ToolForge runs in your browser and sends nothing anywhere, which matters because real payloads carry tokens, customer records and internal identifiers. Before pasting a production response into any other site, check where it is processed.
