JWT Decoder / Encoder
Decode payloads, verify signatures, test secrets, and generate JWT tokens.
URL Encoder & Decoder
Encode special characters in URLs or decode encoded URLs instantly.
Encoding Mode
Input
Output
Characters that remain un-encoded per mode
| Mode | Safe characters (not encoded) |
|---|---|
| encodeURIComponent | A-Z a-z 0-9 - _ . ! ~ * ' ( ) |
| encodeURI | A-Z a-z 0-9 ; , / ? : @ & = + $ - _ . ! ~ * ' ( ) # |
| Form encoding | A-Z a-z 0-9 - _ . ! ~ * ' ( ) (spaces become +) |
What Is URL Encoding?
URL encoding (also called percent-encoding) replaces characters that are not allowed in a URI with a percent sign followed by their hexadecimal byte value. For example, a space becomes %20 and an ampersand becomes %26. This ensures that query parameters, path segments, and fragment identifiers are transmitted without ambiguity across browsers and servers.
Encoding Modes Explained
encodeURIComponent encodes everything except unreserved characters and is the right choice for individual query-string values or path segments. encodeURI leaves URI-structural characters like /, ?, and # intact, making it suitable for encoding a full URL while preserving its structure. Form encoding follows the application/x-www-form-urlencoded specification used by HTML forms, where spaces are replaced with + instead of %20.
Common Use Cases
- Building query strings for REST API calls
- Encoding redirect URLs inside OAuth flows
- Debugging encoded values received from third-party APIs
- Preparing data for
application/x-www-form-urlencodedPOST bodies
Privacy and Security
All encoding and decoding happens entirely in your browser. No data is sent to any server, so you can safely work with tokens, secrets, and personally identifiable information without risk of interception.
FAQs
What is the difference between encodeURI and encodeURIComponent?
encodeURI encodes a full URL but preserves characters that have meaning in URLs (: / ? # @ etc.). encodeURIComponent encodes everything except letters, digits, and - _ . ~. Use encodeURIComponent for query parameter values.
Which characters need to be URL-encoded?
Characters outside the unreserved set (A-Z, a-z, 0-9, -, _, ., ~) should be percent-encoded. Common examples: space becomes %20, & becomes %26, = becomes %3D, and + becomes %2B.
What is form encoding (application/x-www-form-urlencoded)?
Form encoding is used in HTML form submissions. It is similar to encodeURIComponent but also replaces spaces with + instead of %20. This format is used for POST request bodies and query strings.
What is double encoding and how do I avoid it?
Double encoding occurs when already-encoded text is encoded again (e.g. %20 becomes %2520). Only encode raw values once. If you see %25 in your URL, you likely have double-encoded content.
Why do spaces sometimes appear as + and sometimes as %20?
In form encoding (application/x-www-form-urlencoded), spaces are encoded as +. In general percent-encoding (RFC 3986), spaces are encoded as %20. Both are valid in different contexts.
Is Free URL Encoder & Decoder Online — encodeURI vs encodeURIComponent free to use?
Free URL Encoder & Decoder Online — encodeURI vs encodeURIComponent is completely free and runs in your browser.
Does Free URL Encoder & Decoder Online — encodeURI vs encodeURIComponent send my data to a server?
No. Free URL Encoder & Decoder Online — encodeURI vs encodeURIComponent processes input directly in your browser.
Do I need to create an account to use Free URL Encoder & Decoder Online — encodeURI vs encodeURIComponent?
No account is required to use Free URL Encoder & Decoder Online — encodeURI vs encodeURIComponent.
Privacy-first by design
Tool inputs are processed in your browser. Review the Privacy Policy and Terms for full details.
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