%27 is the URL-encoded apostrophe (').
In a URL, %27 stands for the apostrophe ('). Here is when to encode it, what it does in each part of a URL, and what every major language outputs.
Quick facts
| Character | ' |
|---|---|
| Name | Apostrophe (single quote) |
| Unicode | U+0027 |
| UTF-8 bytes | 27 (1 byte) |
| Percent-encoded | %27 |
| Lowercase form | %27 — identical meaning |
| Double-encoded | %2527 |
| HTML form encoding | %27 |
| RFC 3986 class | Reserved — sub-delimiter |
| HTML entity | ' |
What it means in a URL
The apostrophe is a sub-delimiter. encodeURIComponent, Java and Ruby’s form encoder leave it raw; PHP, Python, Go and C# encode it as %27. A raw apostrophe in a URL placed in single-quoted HTML or JavaScript ends the string.
RFC 3986 class: Reserved — sub-delimiter. RFC 3986 allows it raw in paths and queries, but some schemes and servers give it meaning, so encoding it as data is the safe choice.
When to encode it
| Where it appears | What to do |
|---|---|
| Path segment | Allowed raw (encoding is also fine) |
| Query value | Allowed raw (encoding is also fine) |
| Fragment | Allowed raw |
| Form body | Encode |
The mistake to watch for
SQL-injection filters and WAFs that flag %27 in legitimate names such as O’Brien — and code that inserts a raw ' into a single-quoted attribute.
What each language produces
Left as-is by JavaScript encodeURIComponent(s), JavaScript encodeURI(s); every other function in the table encodes it. Output for the single character, UTF-8 input, tested against the real runtimes (see the encoding comparator for your own strings).
| Function | Output | |
|---|---|---|
| JavaScript encodeURIComponent(s) | ' | kept |
| JavaScript encodeURI(s) | ' | kept |
| JavaScript URLSearchParams | %27 | encoded |
| Python urllib.parse.quote(s) | %27 | encoded |
| Python quote(s, safe="") | %27 | encoded |
| Python urllib.parse.quote_plus(s) | %27 | encoded |
| PHP rawurlencode($s) | %27 | encoded |
| PHP urlencode($s) | %27 | encoded |
| Java URLEncoder.encode(s, UTF_8) | %27 | encoded |
| Go url.QueryEscape(s) | %27 | encoded |
| Go url.PathEscape(s) | %27 | encoded |
| Ruby URI.encode_www_form_component(s) | %27 | encoded |
| Ruby ERB::Util.url_encode(s) | %27 | encoded |
| C# / .NET Uri.EscapeDataString(s) | %27 | encoded |
Decoding it
decodeURIComponent('%27') returns the apostrophe ('). Python: urllib.parse.unquote('%27'); PHP: rawurldecode('%27'). Paste any string into the URL decoder to decode it in your browser.
← %26 Ampersand · Full URL encoding table · %28 Left parenthesis →
Common questions.
%27 is the percent-encoded form of the apostrophe ('), whose byte value is 0x27. Decoding the URL turns it back into the character.
Yes. Hex digits in percent-encoding are case-insensitive, so %27 and %27 mean the same thing. RFC 3986 recommends uppercase, and mixing cases can make caches and analytics count one URL as two.
Use your language’s encoder on the value: encodeURIComponent in JavaScript gives ', Python’s quote(s, safe="") gives %27, PHP’s rawurlencode gives %27.
More from the toolkit.
About this page. Written and maintained by Sri Murugan Systems, the developer of urlencodedecode.com. Character classes follow RFC 3986 §2; language outputs were generated by running each function in its real runtime.