URL Builder & UTM Generator Online

Construct and validate fully encoded URLs with UTM or custom query parameters, right in your browser.

The URL Builder runs entirely in your browser. The base URLs, UTM tags, and query parameters you enter never leave your device and nothing is uploaded to ArrayKit.

Built and maintained by Udit Agarwal

Try the URL Parser

About URL Builder & UTM Generator

The URL Builder is a visual form tool that helps developers and marketers construct fully encoded production URLs without manual string concatenation or guesswork. Paste your base URL, then easily toggle and append standard analytics flags like utm_source, utm_medium, and utm_campaign, or define an unlimited array of generic custom query parameters. As you type, it instantly computes a valid, percent-encoded URL with a one-click copy button. It is perfect for preparing links for social media, marketing email campaigns, or API webhooks. Everything runs locally in your browser, so your private endpoints and custom parameters are never uploaded to any server.

Features

  • Construct URLs with dedicated UTM parameter fields for quick analytics tagging
  • Add unlimited custom query parameters as key-value pairs
  • Toggle custom parameters on and off to preview different URL combinations
  • Automatically handles URL encoding and percent-encoding for all parameters
  • Smart protocol handling automatically prefixes missing https:// to your links
  • Safely overwrites or strips existing query parameters from pasted base URLs
  • Runs entirely locally in your browser with zero server uploads

How to use the URL Builder & UTM Generator

  1. Paste your destination link into the Base URL field.
  2. Fill out any standard analytics tags like utm_source or utm_campaign in the UTM Parameters section.
  3. Click 'Add' to append any custom query keys and values you need.
  4. Review the Generated URL output at the bottom and click the copy icon to use it.

Example

Input

Base: https://example.com/promo
utm_source: newsletter
key: user_id, value: 123

Output

https://example.com/promo?utm_source=newsletter&user_id=123

All parameters are combined and automatically URL-encoded.

Common errors & troubleshooting

  • The generated URL contains '%20' or other percent signs. — This is normal and required for a valid URL. The tool automatically encodes spaces to '%20' or '+' and encodes special characters so the link works correctly in browsers.
  • Parameters I added are not showing up in the output. — Check that the toggle switch next to your custom parameter is turned on, and ensure that the key field is not empty.
  • My base URL already had parameters and they got overwritten. — If you define a UTM or custom parameter that shares the same key as one already in the base URL, the tool will append the new one or replace it depending on the parameter type.

Frequently asked questions

What is a UTM Campaign Generator?
It is a tool used by marketers and developers to attach standard tracking tags (like utm_source, utm_medium, and utm_campaign) to a URL, allowing analytics platforms to track where traffic originated from.
Does this tool correctly URL-encode special characters?
Yes. Every parameter key and value is safely percent-encoded using native browser APIs, ensuring your generated URL is valid and won't break when clicked.
Can I add custom query parameters besides UTM tags?
Absolutely. You can add as many custom key-value pairs as you need using the Custom Query Parameters section. You can even toggle them on and off to test variations.
Are my URLs and parameters kept private?
Yes. The URL Builder computes everything locally on your device. Your base URLs and parameter data are never sent over the network or uploaded to our servers.

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