URL Query Builder

How to use

1. Type the base URL. If it already has a `?`, the builder will append the rest with `&`.
2. Add key-value rows. Toggle the checkbox to include / exclude a row without deleting it.
3. 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.

Which characters must be encoded inside a value?

Anything that would otherwise be read as structure: the ampersand, the equals sign, the space, and above all the hash. Everything after a hash is the fragment and is never sent to the server, so one unencoded hash silently cuts the rest of your value off the request. Slashes and colons are legal inside a query string and can be left alone, though encoding them harms nothing.

Does the order of parameters matter?

Not to the server, which is free to read them in any order. It matters everywhere else: caches and CDNs key on the exact URL text, so the same parameters in a different order are a different cache entry, and anything that signs or compares URLs — analytics, signed links, deduplication — sees two distinct strings. Keep the order stable even though nothing forces you to.

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