Browser-first privacy
The website interface converts input locally and does not transmit the pasted value. This is the preferred mode for sensitive samples.
All tools
Developer utility · Guide
Form URL-encoded to JSON
Decode application/x-www-form-urlencoded data with repeated keys, percent escapes, plus-sign spaces, and complete URL support.
Open the tool- Input
- Form body, query string, or URL
- Output
- Formatted JSON
- Processing
- Local in the UI; server-side via API
- Cost
- Free to use
Purpose
What problem does it solve?
Form submissions, OAuth callbacks, webhook samples, and copied URLs frequently arrive as dense key-value strings. Reading percent escapes and repeated fields by eye is slow, and quick split-on-ampersand snippets often lose information.
The converter applies standard form-decoding behavior, accepts raw form data, a leading-question-mark query string, or a complete URL, and groups repeated field names into arrays before producing formatted JSON.
Workflow
From input to useful output.
- 01
Paste the available input
Use a raw form body, a query string, or an entire URL. The interface identifies which part should be parsed.
- 02
Decode using form rules
Percent escapes become characters, plus signs become spaces, empty values remain present, and equals signs inside values are preserved.
- 03
Copy structured JSON
Repeated keys become arrays so values are not silently overwritten. Values remain strings because form encoding carries no JSON types.
Under the surface
Behavior you can reason about.
Repeated keys
Inputs such as tag=design&tag=web become one array rather than retaining only the final value.
Complete URLs
When a complete URL is supplied, the converter parses its query component and ignores the fragment.
Documented API
A versioned JSON endpoint is available for automation. Unlike browser mode, API input necessarily reaches the server for processing and is not persisted by the application.
Known limits
Where this tool stops.
- Form encoding does not represent numbers, booleans, null, or nested objects, so values remain strings.
- Bracket conventions such as user[name] and items[] remain literal key names rather than inferred object structures.
- Malformed percent escapes follow browser URL parsing behavior and may differ from a framework-specific decoder.
- The public API is unauthenticated; use local browser conversion when input should not leave the device.
Questions
Before you use it.
Does the browser converter send my input anywhere?
No. Interactive conversion runs locally. Only deliberate requests to the separate API send input to the server.
Why are numbers and booleans returned as strings?
application/x-www-form-urlencoded has no native JSON value types, so preserving strings avoids guessing and changing the submitted data.
What happens to repeated field names?
Repeated names are preserved in order as an array rather than overwriting earlier values.
Can I automate conversion?
Yes. The tool publishes a versioned API and OpenAPI document on the converter host.