21 Free Online JSON Tools
These 21 JSON tools cover the whole life of a JSON document: reading it, checking it, reshaping it, and turning it into code. Paste a minified payload into the JSON Formatter for readable indentation, run it through the JSON Validator when a parser rejects it and you need the exact line and column, or open the JSON Viewer to collapse the parts you do not care about right now. When JSON has to become something else, there are converters for CSV, XML, YAML, and a flat table view, plus code generators that emit TypeScript interfaces, Go structs, Java POJOs, and C# classes from one sample payload. Schema work is covered too — build a schema by hand, validate a payload against it, or generate one for LLM structured outputs. Every tool here runs entirely in your browser, so payloads carrying customer data or API keys never leave your machine.
All 21 JSON tools
What you can do with these JSON tools
The set breaks down into four jobs, and most debugging sessions use two or three of them in sequence.
- Read and inspect — JSON Formatter for indentation, JSON Viewer and JSON Tree Viewer for collapsible exploration, JSON to Table for a flat Key / Value grid.
- Check and fix — JSON Validator for syntax errors with line and column, JSON Schema Validator for structural rules, JSON Escape / Unescape for payloads that arrived double-encoded.
- Convert — to and from CSV, XML, and YAML, in both directions, with header detection and type inference where it matters.
- Generate code — TypeScript, Go, Java, and C# type definitions from an example payload, so you stop hand-typing models that already exist in the response.
- Compare and compress — JSON Diff for two versions of the same document, JSON Minifier to strip whitespace before shipping.
Choosing the right JSON tool
Three of these overlap enough to be worth separating. JSON Viewer is the one to reach for when a payload is large and you want to collapse branches and search keys. JSON Tree Viewer draws the same data as a diagram with connector lines, which suits explaining a structure to someone else more than debugging it. JSON to Table flattens everything into rows, which is what you want when the payload is really a list of records. On the writing side, JSON Formatter and JSON Minifier are the same operation in opposite directions — format while you work, minify before it ships. And if a value in your JSON looks like "{\"id\":1}" with backslashes, you need JSON Escape / Unescape first; no formatter will fix a string that has been stringified twice.