URL Encoder / Decoder

URL Encoder / Decoder

Encode unsafe query parameters, special symbols, and Unicode strings into safe percent-encoded URLs locally in your web browser. Built with client-side URI engines, this utility formats parameters in memory, ensuring that confidential strings, passwords, or token keys are never transmitted to remote servers.

URL Encoding Specifications & Formats

• Internet Engineering Task Force (IETF): RFC 3986 Uniform Resource Identifier (URI) Standard.
• W3C URL Specification: Web Hypertext Application Technology Working Group (WHATWG) URL Standard.
• Unicode Consortium: Standard Guidelines for UTF-8 Byte Mapping.

URL Encoder Online — Percent-Encoding Query & String Tool

This utility converts characters that are reserved or unsafe for URLs into their percent-encoded equivalents. It takes standard text inputs, replaces special characters (like spaces, ampersands, or question marks) and Unicode symbols with % followed by their hex byte representation, and outputs a valid, safe URL string.

• URL Fails to Load in Browser: Check if the protocol prefix (e.g., http%3A%2F%2F) has been encoded by mistake. If so, decode the string and encode only the parameters.
• Plus Signs (+) Decoded as Spaces: This is standard behavior for query string parsing. Ensure you encode the plus sign as %2B before sending.
• Invalid Character Errors: Ensure your text input contains valid UTF-8 characters.

Why do some characters need to be encoded in a URL?

Because some characters have structural meanings in URLs (like ? to start a query string, or & to separate parameters). If your data contains these characters, they must be encoded to prevent the browser from misinterpreting them as structural delimiters.

What is the difference between encodeURI and encodeURIComponent?

encodeURI is designed to encode a full URL, leaving characters like /, ?, and : untouched. encodeURIComponent is designed to encode a parameter value, converting all reserved characters (including /, ?, and :) into their hex equivalents.

Are my credentials secure when URL encoded?

No. URL encoding is a text formatting standard, not a secure locking method. Anyone can easily decode the string.

• URL Decoder: Convert percent-encoded query structures back into readable text format.
• Word Counter: Count words, characters, sentences, paragraphs, and read times in real-time.
• Character Counter: Real-time character counting supporting standard limit parameters.
• Case Converter: Convert text variables to UPPERCASE, lowercase, Title Case, Sentence case, and camelCase.
• Text Sorter: Sort lines of text alphabetically or numerically in ascending or descending orders.
• Remove Duplicates: Strip duplicate lines from text arrays or lists instantly.

Percent-Encoding Calculation & Worked Example

URL encoding (percent-encoding) is governed by the Internet Engineering Task Force (IETF) RFC 3986 standards:

1. 1Reserved vs. Unreserved Characters:
2. 2Unreserved characters do not require encoding. They include standard English letters, digits, and a few symbols:

Unreserved Set = [a-zA-Z0-9-_.~]

• Reserved characters have structural meanings in URLs (like delimiters or query indicators) and must be encoded if they represent data content rather than structural markers:

Reserved Set = [:/?#[]@!$&'()*+,;=]

1. 2The Hex Conversion Formula:

To encode a character, the engine looks up its UTF-8 byte value and converts it into a hexadecimal representation prefixed by %.

• Example 1 (Space): Space character ASCII value 32 (hex 20) is encoded as %20.
• Example 2 (Ampersand): & character ASCII value 38 (hex 26) is encoded as %26.
• Example 3 (Unicode): The emoji "🚀" is represented by 4 UTF-8 bytes: F0 9F 9A 80. It is encoded as %F0%9F%9A%80.

1. 3Built-in JavaScript Methods:
2. 2encodeURIComponent(): Encodes all characters except unreserved ones. Used for encoding individual parameter values.
3. 3encodeURI(): Encodes only characters that have no structural meaning in a standard URL, leaving protocol (http://) and host separators (/) untouched.

[Input String]
      |
      v
[Determine character type: Reserved, Unreserved, or Unicode?]
      |
      +---> Unreserved -> Leave unchanged
      +---> Reserved ----> Convert to % + Hex ASCII code (e.g. & -> %26)
      +---> Unicode -----> Convert to % + Hex UTF-8 bytes (e.g. 🚀 -> %F0%9F%9A%80)

• Query Parameter Setup: To pass the email address test+user@example.com safely as a parameter:

test%2Buser%40example.com

• Redirection Target Setup: To redirect a user to https://site.com/dashboard?user=123:

https%3A%2F%2Fsite.com%2Fdashboard%3Fuser%3D123

• Unicode Path Slug: To place the folder name "Summer Products ☀️" in a URL path:

Summer%20Products%20%E2%98%80

Edge Cases & URL Precision Limits

• Use encodeURIComponent for parameters: Always encode query parameter values individually before combining them into a query string.
• Keep Credentials Out of URLs: Do not pass passwords or authorization tokens in URL parameters, even if encoded; URLs are stored in browser history and server logs.
• Use Standard UTF-8 Encoding: Ensure your inputs use standard UTF-8 characters to prevent character translation errors on target systems.

Typical Percent-Encoding Errors

• Encoding the Entire URL: Encoding the protocol and domain prefix (e.g., https://example.com), which renders the URL invalid for browsers because structural delimiters (like /) are converted.
• Confusing Spaces representation: In some contexts (like query strings), spaces are represented as a plus sign (+). In standard path segments, they must be represented as %20.
• Not Encoding the Plus Sign (+): Leaving the plus sign unencoded in email parameters, which recipients decode as a space character, breaking email confirmation links (e.g. user+1 becomes user 1).