What this tool does
Decode a query string into a parameter list. Repeated keys are preserved and represented as arrays in the JSON result, rather than overwritten by later values.
- Supports leading question marks, null values, Unicode and repeated keys.
- URLSearchParams will interpret the plus sign as a space according to query form rules.
- The input is only parsed as a string, no URL is accessed or any parameters are sent.
How to use it
- Paste Query String.
- Click "Parse Parameters".
- Check the table for original order and duplicates.
- Copy the JSON result preserving duplicate values.
Common uses
- Debug query parameters in the address bar.
- View the Chinese value after percent encoding.
- Confirm duplicate keys generated by multi-select fields.
Privacy and security
Your input and results stay in your browser and are not uploaded or saved automatically. Copy any results you want to keep and save them yourself before leaving the page.
Query String Parser Features
Parse a query string while preserving repeated parameters, empty values, and standard percent-encoding behavior. Review the result, then copy it for use.
FAQ
Will duplicate Keys be overwritten?
No. All values are retained, and JSON views use arrays for duplicate keys.
Does it have to have a question mark at the beginning?
No, both query strings with and without question marks can be parsed.
Why does the plus sign become a space?
URLSearchParams follows query form encoding rules, where the plus sign indicates whitespace.
Will the URL be requested when parsing?
No, this tool only processes input text.