How to use this developer tool
- Choose JSON, query string, or key-value lines.
- Enter an optional base URL.
- Enable empty-value or tracking cleanup options.
- Build, copy, or download the result.
#071 · Web Meta & Server Files Developer Tool
Query String Builder
Build encoded query strings and complete URLs from key-value parameters while preserving duplicates, empty values, array notation, and parameter order.
Developer Input
Web Meta & Server FilesAd space
What this developer tool does
The tool converts structured parameters into an encoded query string while retaining duplicate values as repeated keys.
Parse input → preserve duplicate keys → encode with URLSearchParams → optionally remove tracking parameters → append to the base URL.
Duplicate keys are preserved with append(), so arrays are not silently overwritten.
Example
Input JSON: {"tag":["css","html"],"page":2}
Output: ?tag=css&tag=html&page=2
Tips for better output
- Use repeated keys for APIs that accept multiple values.
- Remove tracking parameters before sharing clean links.
- Keep a base URL to generate a complete, testable URL.
FAQ
How do I build a URL query string from JSON?
Convert each property to a URLSearchParams entry and append array values as repeated keys.
How do I preserve duplicate query parameters?
Use append instead of set so repeated keys remain in their original order.
How do I remove UTM and click-tracking parameters?
Enable tracking removal to skip utm_ keys, gclid, fbclid, and msclkid.
How do I merge a query string with an existing URL?
Provide the base URL; generated parameters are appended to its existing search parameters.
How do I encode spaces as plus signs in a query string?
URLSearchParams serializes spaces as plus signs in query parameter values.
Related developer tools
Query outputs
| Output | Purpose |
|---|---|
| Query string | Ready to append to a URL |
| Full URL | Complete testable link |
| JavaScript | URLSearchParams implementation |