URL Encoder

How to use the URL Encoder tool

1. Paste the text or parameter value into the left editor, or click Upload File to load it from a .txt file. Click Dummy Data to see a worked example.
2. The right panel encodes as you type using encodeURIComponent(), so every reserved character including / ? & = becomes a percent sequence.
3. If you pasted a complete URL, tick "Encode Full URL (preserve ://)" to switch to encodeURI(), which keeps the scheme, slashes, ? and & intact.
4. Click Copy Result to put the encoded string on the clipboard, or Clear to start again.

How to URL encode a string in JavaScript, PHP and Python

const value = "hello world & more/100%";

// Encode a single query value (matches the tool's default)
console.log(encodeURIComponent(value));
// hello%20world%20%26%20more%2F100%25

// Encode a whole URL but keep :, /, ? and & intact
console.log(encodeURI("https://example.com/search?q=hello world&lang=en"));
// https://example.com/search?q=hello%20world&lang=en

// Build a query string safely (spaces become +)
const params = new URLSearchParams({ q: value, lang: "en" });
console.log(params.toString());

<?php
$value = "hello world & more/100%";

// RFC 3986 encoding: space becomes %20 (same as encodeURIComponent)
echo rawurlencode($value), PHP_EOL;

// Form encoding: space becomes + (application/x-www-form-urlencoded)
echo urlencode($value), PHP_EOL;

// Build a full query string from an array
echo http_build_query(["q" => $value, "lang" => "en"], "", "&", PHP_QUERY_RFC3986), PHP_EOL;

from urllib.parse import quote, quote_plus, urlencode

value = "hello world & more/100%"

# safe="" so the slash is encoded too, like encodeURIComponent
print(quote(value, safe=""))

# Form style: space becomes +
print(quote_plus(value))

# Build a query string from a dict
print(urlencode({"q": value, "lang": "en"}))

Common errors and how to fix them

The API returns 400 or 404 after I encoded the whole URL

encodeURIComponent() turned https:// into https%3A%2F%2F, so the server saw one long path segment. Encode each parameter value separately, or tick Encode Full URL (preserve ://) in the tool to use encodeURI().

Spaces show up as + on one side and %20 on the other

Both are valid, but + means a space only in application/x-www-form-urlencoded data. Use %20 in paths and in URLs you build by hand. If a server sends you + in a query string, replace it with a space before decoding.

Value arrives double-encoded, for example %2520 instead of a space

The value was encoded twice, usually once by your code and once by an HTTP client or framework that encodes automatically. Encode exactly once, at the point where the URL is assembled.

URIError: URI malformed when encoding

The string contains a lone surrogate half, which is not valid UTF-16 and cannot be turned into UTF-8 bytes. This usually comes from slicing a string in the middle of an emoji. Cut strings on grapheme boundaries instead, for example with Intl.Segmenter.

Ampersand in a value splits my parameters

An unencoded & starts a new parameter. Encode the value so & becomes %26, and the server treats it as part of the same value.

Good to know