URL Builder

Construct URLs from protocol, hostname, path, query parameters and hash

What is it and how does it work?

A URL builder constructs a complete, valid URL from its parts — protocol, hostname, path, query parameters and hash — so you assemble a correct address instead of typing it by hand and hoping the punctuation is right. A URL has a precise structure, with each piece joined by specific characters: :// after the protocol, / for the path, ? to start the query, & between parameters and # for the hash. Building it from labelled fields means the separators always land in the right place.

It is the counterpart to a URL parser: where a parser breaks an address apart, a builder puts one together. The part it handles most usefully is the query string — you add parameters as name/value pairs and it encodes any special characters and joins them with & and =, which is exactly where hand-written URLs break. A space or an ampersand inside a value has to be percent-encoded or it corrupts the link, and the builder takes care of that automatically. This tool assembles the URL in your browser, so anything you enter stays on your device.

Common use cases

• Building an API request URL: assemble the endpoint with query parameters correctly encoded and joined.
• Adding tracking parameters: construct a link with UTM or campaign parameters without mistyping the separators.
• Creating a link with safe values: build a URL whose parameters contain spaces or symbols, encoded correctly.

Frequently asked questions

What are the parts of a URL?

A URL is made of the protocol (https), the hostname (example.com), an optional port, the path (/page), the query string (?key=value) and the hash or fragment (#section). Each is joined by specific characters, and a builder places those separators correctly so the address is valid.

Why do query parameter values need encoding?

Characters like spaces, &, = and ? have special meaning in a URL, so if a value contains them they must be percent-encoded — a space becomes %20 — or they break the URL's structure. A builder encodes parameter values automatically, which is the most common source of hand-written URL bugs.

What is the difference between the query string and the hash?

The query string (after ?) is sent to the server and usually carries parameters the page or API reads. The hash (after #) stays in the browser and is not sent to the server — it typically points to a section of the page or is used by client-side apps.

How are multiple parameters combined?

Parameters are written as key=value pairs and joined with an ampersand: ?a=1&b=2. The first parameter follows a ?, and each subsequent one is separated by &. A builder adds these separators for you, so adding or removing a parameter never leaves a stray ? or &.

Network

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