What is URL Encoder & Decoder?
URL encoding (percent-encoding) follows RFC 3986: characters outside the unreserved set (A-Z, a-z, 0-9, - _ . ~) get converted to %XX hexadecimal. This tool supports multiple workflows: `encodeURIComponent()` for parameters, `encodeURI()` for full URLs, form-style encoding where spaces become `+`, and Base64 for text payload transport. It also includes a URL parser, query builder, bulk line processing, and a character reference table for debugging web inputs.
Best For
Fast browser-based workflows that do not require uploading files to a server.
Privacy
Your data stays on your device because processing happens locally in the browser.
Access
Free to use, no account required, and available at https://www.filemint.dev/tools/url-encoder.
Deep Dive: URL Encoder & Decoder
URL encoding (percent-encoding) follows RFC 3986: characters outside the unreserved set (A-Z, a-z, 0-9, - _ . ~) get converted to %XX hexadecimal. This tool supports multiple workflows: `encodeURIComponent()` for parameters, `encodeURI()` for full URLs, form-style encoding where spaces become `+`, and Base64 for text payload transport. It also includes a URL parser, query builder, bulk line processing, and a character reference table for debugging web inputs.
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Privacy Architecture
This tool uses client-side WebAssembly to ensure your data never touches a server. Secure, fast, and privacy-focused by design.
Core Capabilities
- Encode/decode with Component, URI, Form, and Base64 modes
- Live conversion for instant feedback
- Built-in URL parser with query parameter inspection
- Query builder for assembling parameterized URLs
- Bulk line-by-line processing
- Percent-encoding reference lookup
- Handles UTF-8 text and emojis client-side
- Private in-browser processing
Why It Matters
- Reliability: Build and inspect valid URLs without breaking reserved characters.
- Debugging: Decode and parse messy links from logs, APIs, and browsers.
- Productivity: Switch between common URL-safe encoding modes in one place.
- Speed: Process single values or bulk lists instantly in-browser.
- Privacy: Sensitive parameters stay local to your device.
Quick Start Guide
Choose 'Encode' or 'Decode' mode.
Type or paste your text into the input box.
The result appears instantly using encodeURIComponent() or decodeURIComponent().
Click the copy icon to save the result to your clipboard.
Use the 'Clear' button to start over.
Usage Examples
Encode Spaces in URL
Scenario 01Spaces become %20 in URLs
Hello World
Hello%20World
Encode Query Parameters
Scenario 02Special characters in search queries
name=John Doe&email=john@example.com
name%3DJohn%20Doe%26email%3Djohn%40example.com
Decode URL Parameters
Scenario 03Make encoded URLs readable again
product%3Dlaptop%26price%3D%24999
product=laptop&price=$999
Common Scenarios
Building Search URLs
Encode user search queries for URLs safely.
Debugging API Requests
Understand what's actually being sent to the server.
Email Campaign Links
Create tracking URLs with parameters.
Sharing URLs with Special Characters
Share links containing non-English text.
Questions?
Technical Architecture
Reserved vs Unreserved Characters
**Unreserved** (safe, don't need encoding): A-Z, a-z, 0-9, -, _, ., ~ **Reserved** (special meaning, encode if used as data): : / ? # [ ] @ ! $ & ' ( ) * + , ; = **Everything else**: MUST be encoded (spaces, unicode, etc.) When in doubt, encode it! Better safe than broken URLs.
Percent-Encoding Format
Each encoded character becomes %XX where XX is hexadecimal: - Space: %20 - #: %23 - &: %26 - =: %3D - ?: %3F For Unicode: First convert to UTF-8 bytes, then encode each byte. Example: € → UTF-8: [E2, 82, AC] → %E2%82%AC
When to Encode What
**Path** (example.com/path/to/page): Encode spaces, special chars, but NOT forward slashes **Query string** (example.com?key=value): Encode EVERYTHING except & (separator) and = (assignment) **Fragment** (example.com#section): Encode special characters, rarely used Different parts, different rules! Know where your data goes.
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