URL Encoder / Decoder

URL encoding (percent-encoding) converts characters that cannot appear safely in a URL into a '%xx' format, where xx is the hexadecimal byte value. Defined in RFC 3986, it is essential for transmitting Japanese, Chinese, and other multibyte characters, spaces, and special symbols in HTTP requests, query strings, and redirects.

The Three Encoding Modes

encodeURIComponent (recommended) encodes everything except letters, digits, and the characters - _ . ! ~ * ' ( ). It converts spaces, Japanese text, and URL-significant characters like / : ? # & =, making it ideal for query parameter values. encodeURI is designed to encode a complete URL — it leaves / : ? # & = untouched because they have structural meaning in a URL. The 'encode all' mode converts every character including ASCII alphanumerics into %xx form, which is useful for certain custom protocols or obfuscation scenarios.

Automatic Query String Parsing

When you input a query string like name=Alice&age=30&city=Tokyo or a full URL, the tool automatically parses it and displays each key-value pair in a table. This is especially useful when debugging API requests or inspecting URL parameters logged in server access logs.

Common Use Cases

Encode Japanese query parameter values before appending them to API request URLs, decode garbled URLs from browser address bars or log files, inspect and parse query strings from HTTP access logs, verify redirect URL construction in server-side code, and check form POST data or Authorization header values. The query string parser is especially handy when you receive a URL with a long encoded query string and need to understand each parameter without manually splitting on & and decoding. URL encoding is one of the most frequently needed utilities in day-to-day web development and API debugging. It is also essential when constructing OAuth redirect URIs, deep links in mobile apps, and encoded webhook callback URLs.