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URL Query Builder

Build an encoded query string from key-value pairs.

JWT & API ToolsBrowser-only • PrivateFree

Base URL

https://example.com/page?utm_source=newsletter&page=2

Privacy First: All processing happens locally in your browser. Your data never leaves your device and is never uploaded to any server.

About URL Query Builder

The URL Query Builder lets you add key-value pairs and produces a correctly percent-encoded query string ready to append to any URL. It handles the encoding so special characters in your values never break the resulting link or API call. Building runs locally in your browser with nothing uploaded. To take apart an existing query string, use the URL Query Parser, and for campaign links the UTM Builder.

How to Use

1Open URL Query Builder and paste or type your data into the input area.
2Adjust any available options to match the result you want.
3Your output is generated instantly — no button-clicking required for most tools.
4Use the Copy or Download button to save your result.

Common Use Cases

Inspecting JWT claims while debugging authentication
Converting cURL commands into fetch or Axios code
Building and parsing query strings and tracking URLs
Looking up HTTP status codes during API development

Frequently Asked Questions

Are values encoded automatically?

Yes. Each value is percent-encoded as the query string is assembled, so spaces, ampersands, and other special characters are safely escaped and won't break the URL.

Can I build UTM tracking links here?

You can add any parameters including utm_ ones, but for marketing campaigns the dedicated UTM Builder guides you through the standard tracking fields.

Is URL Query Builder free to use?

Yes. URL Query Builder is completely free with no sign-up, no subscription, and no usage limits. Every tool on CodeUtilityKit is free forever.

Is my data safe when I use URL Query Builder?

Absolutely. URL Query Builder runs entirely in your browser. Your input is processed locally with JavaScript and is never sent to, stored on, or logged by any server — so it is safe even for private or sensitive data.