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Free Online JSON Converter and Developer Tools
Format, validate and convert JSON, XML, YAML and CSV directly in your browser. No account, no upload, no waiting.
Everything runs on your device — your data never reaches a server.
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Format, validate, compare and explore JSON documents without leaving the browser tab.
Move data between JSON, XML, YAML, CSV, TSV, HTML tables and query strings with the options each format actually needs.
Turn a JSON sample into typed models for thirteen languages, with the annotations and naming conventions each ecosystem expects.
Encoding, hashing, time, colour, regex and formatting utilities that come up in everyday work.
Each category above shows only the first few tools. Browse all 72 tools to see the complete list, or search by format name.
Why use convert2json
Processed in your browser
Parsing, conversion and code generation all run in JavaScript on your own device. There is no upload step, so a payload from a private staging environment never leaves your machine.
No account, no limits
Nothing is gated behind a sign-up form, a trial, or a daily quota. Open a tool, paste, convert, close the tab.
Fast on real payloads
Documents up to a few megabytes convert in milliseconds. Larger inputs are handed to a background worker so the page stays responsive and the conversion can be cancelled.
Errors you can act on
A failed parse reports the line, the column, the surrounding text and the most likely cause — not a character offset you have to count to by hand.
Works on a phone
The two-pane layout stacks vertically on small screens, controls meet touch target sizes, and every tool is reachable without a mouse.
Keyboard first
Ctrl or Cmd + Enter runs the conversion, Ctrl or Cmd + Shift + C copies the result, and every control is reachable by tab with a visible focus ring.
Working with data formats
Choosing between JSON, XML, YAML and CSV
These four formats are not interchangeable, and most conversion pain comes from pretending they are. JSON has arrays and a small set of scalar types but no comments and no attributes. XML has attributes, namespaces and mixed content but no native array. YAML is JSON plus comments, anchors and significant whitespace. CSV is a flat table with no types at all.
Converting therefore always loses something or requires a decision. Turning JSON into XML means choosing a root element name, because JSON does not have one. Turning XML into JSON means deciding where attributes go. Turning anything into CSV means flattening a tree into columns. Every converter on this site exposes those decisions as options rather than guessing silently.
Why generate types from a real response
API documentation drifts. The response you actually receive is the specification that matters, and generating models from a captured payload catches the field that was quietly renamed last sprint.
The generators here analyse structure recursively rather than pattern-matching text. Nested objects become their own named types, structurally identical shapes are emitted once and reused, array element types are unified, and keys that collide with language keywords are escaped so the output compiles rather than nearly compiles.
A note on sensitive data
Because everything runs locally, pasting a payload here does not transmit it. That said, good habits still apply: production access tokens, customer records and credentials do not belong in any browser tool, ours included. The JWT decoder in particular decodes content only and never verifies a signature, so it should be pointed at test tokens.
If you want to confirm the claim rather than take our word for it, open your browser network panel and run a conversion. You will see no request. Loading the page offline and converting again works for the same reason.
Frequently asked questions
Is convert2json really free?
Yes. Every tool is available without an account, a trial or a usage limit. The site is funded by advertising, which is why you may see ad placeholders in the layout, and no feature is held back behind a paywall.
Does my data get uploaded to a server?
No. All parsing, conversion and code generation happen in JavaScript inside your browser tab. There is no backend that receives your content, which you can verify by watching the network panel while you convert, or by disconnecting from the internet after the page loads.
How large a file can I convert?
File uploads are capped at 25 MB, and in practice the real limit is your browser memory rather than a fixed number. Documents up to a few megabytes convert almost instantly; beyond that the work moves to a background worker so the page stays usable and you can cancel it.
Do the tools work offline?
Once a tool page has loaded, yes. The conversion logic is already in your browser, so it keeps working if you lose your connection. Navigating to a page you have not visited yet still requires the network.
Why are there so many code generators?
Because every language expresses the same JSON shape differently — Go needs struct tags, Swift needs CodingKeys, Rust needs serde attributes, Java needs a serialisation annotation per field. A generic generator would produce code you then have to rewrite, so each language gets its own emitter with its own options.
Can I use the generated code commercially?
Yes. Output generated from your own data is yours, with no attribution requirement and no licence attached by us.
Do you store anything in my browser?
Only your light or dark theme preference, in localStorage. Documents you paste are held in memory for the life of the page and are gone when you close the tab.
Your data stays on your device
Your data is processed locally in your browser and is not uploaded to our server. This page keeps working after you go offline, because there is nothing to send. Read the full privacy policy for details on cookies and analytics.
브라우저에서 처리되는 JSON 변환·포맷·검증 도구