About this tool

JSON Mutual Conversion Postman Parameters Tool

Convert JSON to Postman query params, form-data, x-www-form-urlencoded bodies, raw JSON, dynamic headers, and cURL with real-time two-way parsing.

The JSON Mutual Conversion Postman Parameters Tool moves an API payload between the four shapes a request can take — nested JSON, a query string, a form-data key list and an x-www-form-urlencoded body — and back again. Nested objects are flattened with dot notation (`user.role`), arrays are emitted in whichever of three conventions your backend expects (`tags[]`, a repeated `tags`, or indexed `tags[0]`), and parsing in the reverse direction rebuilds the nesting and coerces `true`, `false`, `null` and numeric strings back to real JSON types. Each conversion also produces the matching Content-Type header and a ready-to-run cURL command.

How to use JSON Mutual Conversion Postman Parameters Tool

1. 1

   Open JSON Mutual Conversion Postman Parameters Tool on AltFTool — it loads instantly in your browser.

2. 2

   Paste the payload into the Live Input Editor, or use Upload for a .json, .txt or .csv file.

3. 3

   Choose a Conversion Mode - JSON to Query Params, JSON to form-data, JSON to x-www-form-urlencoded, Params to JSON or Raw JSON - and an Array Handling chip: tags[], tags or tags[0].

4. 4

   Copy the Synced Output Preview or Download it as output.json or params.txt, with Dynamic Headers and Dynamic cURL generated beside it.

Why use JSON Mutual Conversion Postman Parameters Tool

• Three array conventions, one click

  Switch between bracket, repeated-key and indexed array encoding instead of rewriting every element by hand.

• Round-trips with types intact

  Going back from parameters to JSON restores nesting from dot and bracket paths and converts `true`, `false`, `null` and numeric strings to their JSON types.

• cURL and headers come with it

  Every mode emits the right Content-Type and a matching cURL command — GET with the query appended, POST with the body attached.

Common use cases

• You have a working JSON request body and the endpoint you are now calling only accepts x-www-form-urlencoded, so you need the equivalent encoded body without hand-escaping it
• A colleague sent a long query string from a browser network tab and you want it as structured JSON, with `user.active=true` becoming a real nested boolean
• Your API rejects array parameters and you need to try `tags[]`, plain repeated `tags` and `tags[0]` to find out which convention its framework actually parses

Frequently asked questions