Query String Parser

About this tool

The query part of a URL carries key-value parameters after the question mark, using percent encoding and often repeated keys. The Query String Parser converts a full URL or raw query string into readable JSON and can rebuild a query string from a JSON object.

Repeated parameters such as tag=php&tag=seo may represent an array, while plus signs are commonly decoded as spaces in form-style encoding. The order of parameters usually should not affect server behavior, but signatures and caching systems can be sensitive to normalization. Do not place passwords or long-lived secrets in query strings because URLs are frequently stored in browser history, server logs and analytics systems. For general URL-safe text slugs, use the URL Slug Generator.

How to use it

1. Select query-to-JSON mode and paste either a full URL or only the text after the question mark.
2. Keep repeated keys as arrays when the receiving application treats them as multiple values.
3. Convert and inspect decoded spaces, Unicode characters and empty values.
4. Switch to JSON-to-query mode when building parameters from a simple object.
5. Copy the result and test it against the exact framework or API that will parse it.

Useful ways to apply it

• Inspecting tracking, filter and pagination parameters in a copied URL.
• Turning an API query into JSON for easier debugging and comparison.
• Building a correctly percent-encoded query from a small object.
• Checking how repeated keys and blank values are represented.
• Finding double-encoding or unexpected plus/space behavior.