⚡ 4 Encoding Modes & Query Parameter Builder

URL Encoder Online

Encode URLs, text, and query parameters into percent-encoded format (RFC 3986 §2.1, Full URL, Form x-www-form-urlencoded, Strict 100%) with URL Structure Inspector and 100% browser privacy.

How to Use the URL Encoder

1

Select Input Mode

Choose Plain Text / URL, Interactive Query Parameter Builder, or Multi-line Batch Mode.

2

Select Encoding Mode

Select Component RFC 3986 (Default), Full URL, Form x-www-form-urlencoded, or Strict 100% Percent Encoding.

3

Set Space Encoding

Choose %20 for standard URI components or + for HTML form data.

4

Inspect & Copy

Inspect the URL Structural Inspector, Percent-Encoding Matrix, and copy output.

Understanding Percent-Encoding, RFC 3986 Standards, & Web URL Mechanics

Percent-encoding is a mechanism for encoding information in a Uniform Resource Identifier (URI) defined in RFC 3986. Characters that are reserved, unprintable, or outside the ASCII range must be replaced with a % followed by two hexadecimal digits representing the UTF-8 byte code.

Comparing RFC 3986 vs RFC 1738 vs HTML5 Form Encoding

Encoding ModeSpace EncodingReserved Delimiters EncodedPrimary Use Case
Component Mode (RFC 3986 §2.1)%20Yes (:, /, ?, #, &, =, +)Query parameter values
Full URL Mode (encodeURI)%20No (Preserves syntax)Complete URLs & href links
Form x-www-form-urlencoded+ (plus)YesHTML form submissions & POST requests
Strict 100% Percent Mode%20100% of all charactersWAF rule testing & payload analysis

100% Local Browser Privacy & Security

URLs and query strings often contain API tokens, OAuth redirect targets, or internal session tokens. Our URL Encoder runs 100% locally in your web browser using JavaScript Web Workers. Zero URLs or data leave your machine.

Frequently Asked Questions

What is URL Encoding (Percent-Encoding)?

URL encoding (or percent-encoding) replaces unprintable or reserved URI characters with a "%" followed by two hexadecimal digits representing the UTF-8 byte value (e.g. space becomes %20).

What is the difference between encodeURIComponent and encodeURI?

encodeURIComponent (Component Mode / RFC 3986 §2.1) encodes all reserved URL characters (including /, ?, :, #, &, =, +) and is intended for query parameter values. encodeURI (Full URL Mode) preserves structural URL syntax while percent-encoding spaces and illegal characters.

When should I use + instead of %20 for space encoding?

Use + for HTML form submissions (application/x-www-form-urlencoded / RFC 1738). Use %20 for standard RFC 3986 URI component values.

What is Strict 100% Percent Encoding?

Strict mode percent-encodes every single character (including ASCII letters A-Z, a-z, and numbers 0-9) into %XX hex bytes. It is used by security engineers for testing WAF rules and obfuscation.

How does the Interactive Query Parameter Builder work?

The Query Parameter Builder provides a key-value table interface allowing you to add, edit, or remove parameters with automatic percent-encoding per row.

How are multibyte UTF-8 Unicode characters and emojis encoded?

Multibyte UTF-8 characters (like emojis 🚀 or non-Latin scripts) are decomposed into individual UTF-8 bytes and percent-encoded per byte (e.g. 🚀 becomes %F0%9F%9A%80).

Is my URL input or API key uploaded to any server?

No. 100% of encoding, URL parsing, and matrix visualization runs locally inside your web browser using JavaScript Web Workers. Zero data leaves your machine.

Can I batch encode multiple URLs at once?

Yes! Switch to "Multi-line Batch Mode" to encode multiple URLs simultaneously (one per line).

What is the URL Structural Inspector?

The URL Structural Inspector parses an input URL into protocol, hostname, pathname, query parameters table, and hash fragment.

Can I swap between encoding and decoding?

Yes! Click the "Switch to Decode" button or navigate to /encode-decode/url-decode to decode percent-encoded strings back to plain text.

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