URL encoding: decode %20, fix broken query strings, and avoid double-encoding

If a link contains %20, %2F, or %3D, it has been URL-encoded. Decoding it makes the value readable again, which is often the fastest way to debug redirects, tracking links, and API requests.

Start here:

• Open the URL encoder/decoder.
• Paste the encoded value and switch to Decode from URL.
• If you are building tracking links, use the UTM builder to avoid mistakes.

URLs allow only a limited set of characters in certain places. URL encoding (percent-encoding) replaces special characters with a % followed by two hex digits so they can travel safely through browsers, servers, and analytics tools.

For example, a space becomes %20, and = becomes %3D.

If you want the formal rules, RFC 3986 defines percent-encoding and reserved characters.

You almost never want to encode an entire URL by hand. You usually want to encode only the parts that are values:

• a query parameter value
• a redirect URL that is nested inside another URL
• a piece of JSON you are sending as a parameter

If you encode the whole URL, you will often turn : and / into %3A and %2F, which can make the result harder to reason about.

Double-encoding in practice

If you start with:

https%3A%2F%2Fexample.com%2Fpricing%3Fplan%3Dpro%26ref%3Demail

That decodes to:

https://example.com/pricing?plan=pro&ref=email

If instead you see %253A%252F%252F patterns, decode once to get back to %3A%2F%2F, then decode again to get the readable URL.

Decode a campaign parameter

Encoded value:

black%20friday%202025

Decoded value:

black friday 2025

This is common in utm_campaign, utm_content, and ref parameters.

Decode a nested redirect URL

Login flows often include a redirect parameter:

redirect=https%3A%2F%2Fapp.example.com%2Fbilling%3Ftab%3Dinvoices

Decode the part after redirect= to see the destination clearly.

Decode URL-encoded JSON

Some systems shove JSON into a query param:

%7B%22plan%22%3A%22pro%22%2C%22seatCount%22%3A3%7D

Decoded text:

{"plan":"pro","seatCount":3}

Then format it with the JSON formatter so you can spot missing quotes, commas, or unexpected fields.

• If you need UTM tags, use the UTM builder. It uses URLSearchParams, which handles encoding for you.
• If you need a stable path segment, generate a slug with slugify instead of encoding a full title.
• If a value is already encoded, avoid encoding it again. Double-encoding is how %2520 happens.

1. Open the URL encoder/decoder.
2. Choose Decode from URL to make values readable, or Encode for URL before you paste values into a query string.
3. Copy the output.

Should I encode spaces as + or %20?
In URLs, %20 is the safe default. + is used by form encoding, and some decoders do not treat it as a space unless you convert it first.

Why does decoding fail on some inputs?
Percent-encoding must be valid. Every % must be followed by two hex digits (0-9, A-F). One broken sequence can make the whole string fail.

Does Textavia send my URLs to a server?
No. URL encoding and decoding runs locally in your browser.

• Decode one layer at a time. Stop when the output is readable, and the %.. sequences are gone.
• If you are debugging a redirect parameter, decode only the parameter value, not the entire URL.
• When you see %3D and %26 in Base64-looking strings, URL-decode first, then use the Base64 tool.

• Build tagged campaign links with the UTM builder.
• Create clean path segments with slugify.
• Format decoded JSON with the JSON formatter.

URL encoding runs locally in your browser. Your text is not uploaded to a server.