JSON Tools
Format, validate, compare, and convert JSON in this browser. Nothing is uploaded.
8 tools · 100% browser-based · No uploads · No signup
About these JSON tools
JSON is the default payload for APIs, config files, and browser storage. These tools format, validate, compare, and convert JSON in the page you already have open. Nothing is posted to a server, which matters when the payload includes tokens, PII, or internal URLs.
Start with the formatter if the document is minified or you need to see structure. Use the validator when a parser fails and you want the first syntax error with a line number. Diff two responses after an API change. The table and visualizer views help when an array of objects is easier to scan than nested braces.
Tools in this category
JSON Formatter
Pretty-print is not the hard part. The first syntax error is, and JSON will not mention the second one until you fix the first.
JSON Validator
Check whether a document is valid JSON and jump to the first parse error.
JSON Diff
Compare two JSON values structurally. Key order and whitespace do not count as changes.
JSON → Table
Turn a JSON array of objects into a sortable table you can copy as CSV or Markdown.
JSON Visualizer
Browse a JSON document as an expandable tree and search for keys or values.
Type Generator
Infer TypeScript interfaces or Go structs from a sample JSON payload.
Path Tester
Run JSONPath expressions against a document and inspect the matched values.
Relationship Visualizer
View object relationships as a node graph you can pan and zoom.
How these tools run in your browser
Every JSON tool here calls JSON.parse and related helpers in your browser. Large documents stay in memory on this tab. We do not stream the text to OneDev or a third-party formatter API.
JSONPath testing evaluates expressions against the parsed object. The type generator infers types from the values it sees, so optional fields that are missing in the sample will not appear. Diff compares parsed structures, not raw strings, so key order and whitespace do not count as changes.
Common Use Cases
- Pretty-print a minified API response before you file a bug
- Check a hand-edited config for a missing comma or trailing comma
- Compare staging and production JSON without uploading either file
- Turn a JSON array into a sortable table or export CSV
- Generate TypeScript interfaces or Go structs from a sample payload
Common Mistakes
Frequently Asked Questions
The text never leaves this browser tab. Still treat secrets with care: a compromised extension could read the page. For highly sensitive dumps, prefer a local editor.
JSON is stricter than JS. Keys must be double-quoted, there are no comments or trailing commas, and undefined is not a value. Convert the literal to JSON first.
The formatter pretty-prints and will refuse invalid input. The validator is better when you only need the error location and do not want the document rewritten.