Online URL Encoder and Decoder for Percent Encoding, Query Strings, and Form Mode

• Encode to percent-encoding

  Convert spaces, Unicode text, emoji, and reserved symbols into percent-encoded output for query values, path segments, and callback URLs.

• Decode from percent-encoding

  Turn %XX sequences from browser URLs, logs, redirects, and third-party callbacks back into readable text for inspection.

• Form-data mode

  Handle the space and + convention used by application/x-www-form-urlencoded payloads, form posts, and legacy query strings.

• Full-encode mode

  Full URL mode preserves structure characters such as :, /, ?, &, =, and #, while value mode treats them as plain content.

• Bidirectional swap

  Send output back into the input area to compare strict decode, tolerant decode, form mode, and standard percent-encoding behavior.

• Instant copy and clear

  Copy clean results into API clients, code snippets, or documentation, then clear the editor for the next link.

1. 1

   Select Encode or Decode to set the conversion direction.

2. 2

   Type or paste your input into the text area.

3. 3

   The result updates in real time in the output area.

4. 4

   Use Copy to grab the output, or Swap to exchange input and output.

5. 5

   Toggle form-data mode or full-encode mode depending on your use case.

• Use text/value mode for one parameter value so ?, &, and = are encoded as content.
• Use full URL mode for an already assembled URL so the protocol, path, query string, and fragment stay intact.
• Use query mode when you only need to transform a=1&b=2 style parameters, with control over keys and values.
• Enable form mode when plus signs should be interpreted as spaces in form payloads or legacy query strings.

• Query parameter encoding

  Encode search terms, filters, pagination state, and multilingual tags before appending them to a query string.

• API request preparation

  Encode path segments and parameter values separately when composing REST requests, webhook URLs, or temporary debugging links.

• Form submission debugging

  Decode form payloads from developer tools, gateway logs, or server logs to verify the actual submitted values.

• Data extraction from URLs

  Inspect redirect chains, OAuth callbacks, SSO parameters, and share links by decoding fields such as redirect_uri, state, and next.

• Multilingual parameter handling

  Handle Chinese, Japanese, Korean, emoji, and mixed punctuation consistently across browsers, proxies, and backend frameworks.

• Campaign and tracking link cleanup

  Clean up UTM fields, ad redirects, and channel links that contain nested or repeated encoding before reporting or archiving.

• First identify whether the input is a full URL, one parameter value, or a query string. That choice controls which characters must be preserved.
• If the string already contains segments such as %E4%BD%A0, decode and inspect it before encoding again to avoid turning % into %25.
• For API parameters, think in encodeURIComponent terms; for complete URLs, preserve structural characters such as :, /, ?, &, =, and #.
• Use form mode only for application/x-www-form-urlencoded data. General URL parameters usually represent spaces as %20 rather than +.
• Leftover isolated percent signs, half UTF-8 sequences, or unreadable output usually means the source log was truncated, escaped twice, or mixed with non-URL-encoded text.
• URL encoding is a transport-format tool, not a privacy or security layer. Inspect tokens, signatures, or hashes separately when credentials are involved.
• Document team rules for spaces, Unicode, array parameters, and redirect_uri values so frontend and backend code do not drift apart.

For auth headers, API credentials, or text that needs Base64 conversion, use the Base64 Encode & Decode tool. For Token header, payload, and expiry inspection, open the JWT Inspector tool. When the task expands from one parameter to full URL parsing, domains, paths, query items, and fragments, pair this page with URL Tools .

• Percent-encoding is a formatting convention, not a security mechanism. It does not encrypt, hash, or protect data in any way.
• Double-encoding happens when an already-encoded string is encoded again. This page does not automatically detect double-encoding.
• Very long input strings may cause performance slowdowns in browser rendering. This page is designed for typical text payloads.
• This page uses the browser native encodeURI, encodeURIComponent, decodeURI, and decodeURIComponent APIs for standard encoding operations.
• Form mode focuses on the common space and + difference; it does not simulate a complete form serialization pipeline.
• Tolerant decode is designed for dirty or legacy inputs; use strict mode for protocol validation and QA checks.
• Query mode assumes standard & and = separators. Custom protocols, nested query strings, and unusual delimiters may need manual review first.