JSON to Form Data

Every time a browser submits a form, it sends application/x-www-form-urlencoded data: percent-encoded key=value pairs joined with &. When you need to reproduce that body from a JSON object — for an integration test, a curl command or a mock server — doing the encoding by hand is slow and full of edge cases (spaces, &, =, Unicode).

Convert JSON to Form Data flattens a JSON object into valid form encoding with one click. Nested objects become user[name] paths, arrays become items[0] indices, values are URL-encoded, and you can choose between the compact body string and readable key=value lines.

• Bracket-path nesting: user[name] and items[0][name] forms for nested objects and arrays.
• URL-encoded output: A ready-to-send application/x-www-form-urlencoded body string.
• Readable mode: Decoded key=value lines for eyeballing and debugging.
• Framework-friendly: Express, PHP, Rails and Spring parse the bracket paths back into structures.
• Typed literals: Numbers, booleans and null become their text form, as form data is always textual.
• Live preview: Output updates as you type.
• Copy and download: Grab the body for curl, fetch or Postman instantly.
• Private: All processing happens in your browser; nothing is uploaded.

1. Paste your JSON object into the input pane.
2. Pick the output style — the urlencoded body or readable lines.
3. Copy the body and use it with curl --data, fetch or Postman.
4. Or download the lines for review.

Example 1 — curl reproduction. A developer captures a form submission as JSON in devtools, converts it here, and pastes the body into curl --data "user[name]=Ada&port=5432" to reproduce the request from the terminal.

Example 2 — Mock server. An integration team generates expected request bodies for a mock from their JSON fixtures, guaranteeing byte-identical form data for the test run.

Example 3 — Framework debugging. A PHP engineer converts a payload to form lines to confirm how bracket notation maps onto $_POST nesting before writing the handler.

Example 4 — API documentation. A writer includes a form body example in docs, generated from the JSON version so the two never drift apart.

• Correct encoding: Percent-encoding matches browser behavior for every character.
• Structure preserved: Bracket paths carry nesting and array order.
• Immediately usable: Paste the body straight into curl, fetch or Postman.
• Zero data movement: The document is converted locally and never uploaded.
• Instant results: Live output updates with every keystroke.