When do I use `+` for spaces?

When the server treats the query string as `application/x-www-form-urlencoded` — most older form handlers and CGI scripts do. Modern REST APIs typically accept either, but the safe default for `application/json` POST bodies is `%20`.

Are duplicate keys allowed?

Yes — most servers treat repeated keys as an array. Some only keep the last; check the API docs if you're unsure.

URL Query Builder

A clean form for adding, editing, and disabling query parameters one by one, with the resulting URL built live. Keys and values are run through `encodeURIComponent`; you can choose whether to keep spaces as `%20` or fold them to `+` (the form-urlencoded variant). Disabled rows stay in the list but don't appear in the output — handy for stashing alternatives without losing them.

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Base URL

Parameters (3)

Spaces as:

Built URL

https://api.example.com/search?q=cloudflare%20workers&page=1&sort=relevance

Keys and values are percent-encoded with encodeURIComponent — same rules every well-behaved client uses.

How to use

Type the base URL. If it already has a `?`, the builder will append the rest with `&`.
Add key-value rows. Toggle the checkbox to include / exclude a row without deleting it.
Pick `%20` or `+` for spaces depending on whether the server expects standard URI encoding or form-encoded.

Frequently asked questions

When do I use `+` for spaces?: When the server treats the query string as `application/x-www-form-urlencoded` — most older form handlers and CGI scripts do. Modern REST APIs typically accept either, but the safe default for `application/json` POST bodies is `%20`.
Are duplicate keys allowed?: Yes — most servers treat repeated keys as an array. Some only keep the last; check the API docs if you're unsure.

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