What is the difference between encodeURIComponent and encodeURI?

encodeURIComponent escapes every character that has meaning in URI components (including ?, #, /, &, and =), so it is safe for query parameter values and form fields. encodeURI leaves those structural characters intact and is meant for encoding an entire URI while preserving its syntax. Use encodeURIComponent for values you embed inside a query string; use encodeURI when you need to encode a mostly-valid URL string without breaking delimiters.

Why does decoding fail with “URI malformed”?

That usually means the percent-encoding is invalid—for example a lone %, an incomplete % sequence, or the wrong encoding mode. Try switching between encodeURIComponent and decodeURIComponent versus encodeURI and decodeURI to match how the string was produced. Also ensure copied text was not truncated or corrupted.

Is URL encoding the same as encryption?

No. Percent-encoding only maps characters to a safe ASCII representation so URLs and forms can transport special characters. Anyone can decode it instantly. Never rely on URL encoding for secrecy or authentication.

Does this tool send my data to a server?

No. Encoding and decoding run entirely in your browser. Your strings stay on your device unless you choose to share them elsewhere.

What is “auto-encode on paste”?

When enabled, pasting into the decoded field replaces its contents and immediately fills the encoded field using your selected mode (encodeURIComponent or encodeURI). It saves a click when you are batch-processing plain text into encoded form.

Free URL Encoder & Decoder Online

URL Encoder & Decoder

Encoding:encodeURIComponentencodeURIAuto-encode on paste

Decoded text

0 chars

Percent-encoded

0 chars

Input is capped at 500,000 characters. Use Encode for plain → percent-encoding, Decode for the reverse. Match the mode to how the string will be used (query values vs full URLs).

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What is URL encoding?

URL encoding (percent-encoding) represents characters outside the unreserved set as a percent sign followed by two hexadecimal digits, for example %20 for a space. It keeps URLs, query strings, and form submissions safe when characters would otherwise break parsing or conflict with reserved delimiters like ?, &, and #.

Browsers and HTTP clients apply encoding automatically in many cases, but developers still need encoders when building links by hand, debugging APIs, or comparing client versus server behavior.

How to use this tool

Choose encodeURIComponent for values (query parameters, path segments in APIs) or encodeURI when preserving URL structure matters.
Type or paste text in the Decoded pane and click Encode, or paste an encoded string in the Percent-encoded pane and click Decode.
Use Swap to exchange panes when iterating between plain and encoded forms.
Enable Auto-encode on paste to update the encoded pane immediately when you paste into decoded text.
Copy either side with the per-pane Copy buttons; character counts help compare lengths before and after encoding.

Common use cases

Query parameters: Encode names and values that contain spaces, slashes, or unicode before appending them to a URL.
OAuth and redirects: Inspect redirect URIs and state parameters where encoding mistakes cause “invalid_request” errors.
Deep links and analytics: Verify campaign URLs and deep-link payloads match what servers expect after decoding.
Debugging: Compare raw versus encoded representations when logs show percent-encoded values.

Tips for correct encoding

Always decode with the same family of functions used to encode: pairing encodeURIComponent with decodeURIComponent, and encodeURI with decodeURI. Mixing modes on strings that include reserved characters often yields double-encoding or decode errors.

For international text, JavaScript encodes UTF-8 bytes as percent sequences. If you see unexpected sequences, confirm the source text is valid Unicode and that no intermediate layer has already encoded the string twice.

Frequently asked questions about URL encoding

What is URL encoding?

Browsers and HTTP clients apply encoding automatically in many cases, but developers still need encoders when building links by hand, debugging APIs, or comparing client versus server behavior.

How to use this tool

Choose encodeURIComponent for values (query parameters, path segments in APIs) or encodeURI when preserving URL structure matters.

Type or paste text in the Decoded pane and click Encode, or paste an encoded string in the Percent-encoded pane and click Decode.

Use Swap to exchange panes when iterating between plain and encoded forms.

Enable Auto-encode on paste to update the encoded pane immediately when you paste into decoded text.

Copy either side with the per-pane Copy buttons; character counts help compare lengths before and after encoding.

Common use cases

Query parameters: Encode names and values that contain spaces, slashes, or unicode before appending them to a URL.

OAuth and redirects: Inspect redirect URIs and state parameters where encoding mistakes cause “invalid_request” errors.

Deep links and analytics: Verify campaign URLs and deep-link payloads match what servers expect after decoding.

Debugging: Compare raw versus encoded representations when logs show percent-encoded values.

Tips for correct encoding