URL Decode Online — decodeURIComponent & decodeURI

Reverse percent-encoding on query strings and URLs. Opens in Decode mode — pick component, full URI, or form-urlencoded scope, then click Convert.

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URL encoder & decoder — query strings vs full URLs
Modern browsers expose encodeURIComponent for isolating parameter keys and values, while encodeURI targets entire href strings that still need :, ?, # and other structural symbols intact. FastMinify mirrors both APIs so you can reproduce backend behaviour during debugging.

Choosing the right encoding mode

Encode component mirrors encodeURIComponent: spaces become %20, slashes become %2F, ampersands become %26. Perfect when you craft query pairs programmatically or reverse-engineer analytics URLs. Encode URI mirrors encodeURI: reserved structural characters remain untouched while Unicode code points still gain percent escapes. Form data mirrors application/x-www-form-urlencoded: like component mode but spaces become + instead of %20. Decode performs the inverse transformation using decodeURIComponent or decodeURI respectively. Click Convert to run — conversions are not automatic while you type.

Choosing an encoding scope

Query component (encodeURIComponent)
Encodes every reserved character in a single parameter name or value. Spaces become %20, slashes become %2F, ampersands become %26. Use this when building ?key=value pairs for fetch, OAuth scopes, or analytics payloads.
Full URL (encodeURI)
Escapes Unicode and unsafe bytes while keeping URL scaffolding intact — :, /, ?, #, and & stay literal. Use when sanitizing an almost-complete href without mangling delimiters.
Form data (application/x-www-form-urlencoded)
Encodes like encodeURIComponent but turns spaces into + instead of %20. This mirrors how browsers serialize HTML <form> fields in POST bodies — not how query strings in links are typically built.

Quick comparisons

encodeURIComponent for parameters

Sample input

https://api.example.com/v2/search?q=hello world&filter=a&b&category=home office&price=$100&currency=USD&region=eu-west-1&sort=relevance&page=2&trace=abc123

Sample output

https%3A%2F%2Fapi.example.com%2Fv2%2Fsearch%3Fq%3Dhello%20world%26filter%3Da%26b%26category%3Dhome%20office%26price%3D%24100%26currency%3DUSD%26region%3Deu-west-1%26sort%3Drelevance%26page%3D2%26trace%3Dabc123

encodeURI keeps URL scaffolding

Sample input

https://shop.example.com/catalog?tag=sale%20items&sort=price

Sample output

https://shop.example.com/catalog?tag=sale%2520items&sort=price

Explore neighbouring tools

Binary payloads often ride alongside URLs — use the Base64 encoder. Escaping markup before injecting strings into templates belongs to the HTML entities utility, and shipping compressed bundles stays painless via CSS minification.

URL encoding FAQ

Solidify percent-encoding behaviour before touching APIs

Why does encodeURIComponent throw URI malformed?

decodeURIComponent surfaces errors when percent sequences are incomplete (% alone) or reference invalid UTF-8 bytes.

Should spaces become + or %20?

encodeURIComponent yields %20 — the default for REST query strings. Use the Form data scope when you need + for spaces, matching application/x-www-form-urlencoded bodies from HTML forms.

Does encodeURI protect XSS?

No — escaping URLs prevents delimiter breakage but never substitutes contextual HTML encoding.

Can I encode entire UTF-8 paths?

Yes — encodeURIComponent encodes outside ASCII automatically while preserving surrogate pairs.

Does FastMinify log URLs?

No server round-trip occurs; everything executes locally.

When should I use decodeURIComponent?

Use it to reverse strings produced by encodeURIComponent—typically query parameter names and values—before displaying or re-encoding them.

Does the tool handle non-ASCII text?

Yes. UTF-8 sequences are percent-encoded the same way modern browsers do before a request leaves the client.

Can I mix encodeURI and encodeURIComponent?

Usually you pick one strategy per layer: encodeURI for an almost-complete href, encodeURIComponent for each key and value you append to the query string.

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