URL Encoder & Decoder — Percent-Encode URLs & Query Strings
Encode and decode URLs and query string parameters. Percent-encoding for safe transmission.
How to use
- 1 Pick Encode or Decode mode.
- 2 Choose Component for query params, or Full URL for entire URLs.
- 3 Paste your input and copy the result.
Why use this tool
- Two variants — encodeURIComponent for individual params, encodeURI for full URLs.
- Real-time bidirectional — switch modes and swap input/output in one click.
- Runs in your browser — your URLs stay private.
- Free, no signup, no ads.
Frequently asked questions
When should I use encodeURIComponent vs encodeURI?
Use encodeURIComponent for query string values and path segments (encodes / ? & = #). Use encodeURI for an entire URL string when you want to preserve those structural characters.
Does this support special characters?
Yes — full Unicode support. Emoji, CJK, Arabic, and combining characters are all encoded correctly.
Why does my decode fail?
Invalid percent-encoding (e.g. "%XY" where XY isn't valid hex) throws a URIError. Check that every "%" is followed by exactly 2 hex digits.
What is URL Encoder & Decoder?
A URL Encoder & Decoder is a tool that converts text and query-string parameters to and from percent-encoded form, replacing reserved or unsafe characters with %-prefixed escape sequences so values transmit safely within a URL. It also reverses the process to recover the original text. It runs entirely in the browser, keeping the input on the user's device.
Features
Encode & decode
Percent-encode text for a URL or decode %-sequences back to readable text.
Component & full-URL modes
Escape a single value, or encode a whole URL while preserving its structure.
100% private
Runs client-side — your URLs and parameters never leave the browser.
Example
Input
https://zerethon.com/s?q=hello world&x=1Output
https%3A%2F%2Fzerethon.com%2Fs%3Fq%3Dhello%20world%26x%3D1Common use cases
-
1
Pass values in query strings
Encode a search term or parameter so spaces and & = ? symbols don't break the URL.
-
2
Fix broken links
Decode a %20/%2F-riddled URL to read it, or re-encode a value that was pasted raw.
-
3
Build redirect / OAuth URIs
Percent-encode a redirect_uri or state value before placing it in an authorization URL.
How URL Encoder & Decoder compares to alternatives
| Feature | Zerethon Tools | Typical online tools | Desktop apps |
|---|---|---|---|
| Signup required | No | Sometimes | No |
| Data leaves device | No | Yes | No |
| Encode + decode | Both | Both | Both |
| Component vs full-URL mode | Yes | Sometimes | Sometimes |
| Free | Yes | Yes | Sometimes paid |
| Works offline | Yes (after load) | No | Yes |
Zerethon's URL encoder/decoder percent-encodes and decodes text and query-string values in your browser, following RFC 3986. Component mode escapes every reserved character (like encodeURIComponent) so a value is safe to embed in a URL; full-URL mode leaves structural characters intact. Nothing is uploaded.
- Category
- Developer
- Pricing
- Free
- Privacy
- Browser-based
- Signup
- Not required
References
Privacy
Your data never leaves your browser unless explicitly stated. URL Encoder & Decoder runs entirely client-side — no server upload, no logging, no tracking of your input.
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Learn the basics
How-to guides
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