Encode & Decode Online: Base64, URL, HTML & More (Free Tool)
Encoding transforms data into a different format for safe transmission, storage, or display. Whether you’re debugging a Base64 string from an API, encoding a URL parameter, or escaping HTML entities, you need a reliable encode/decode tool.
Use the MetisTools free encode/decode tool for all common encoding formats.
Encoding Types Explained
Base64
Converts binary data to ASCII text using 64 characters (A-Z, a-z, 0-9, +, /). Used everywhere: email attachments (MIME), data URIs, JSON Web Tokens, and API authentication headers.
URL Encoding (Percent Encoding)
Replaces unsafe characters with % followed by two hex digits. Spaces become %20, & becomes %26. Essential for query parameters and form submissions.
HTML Entity Encoding
Converts special characters to HTML entities: < becomes <, > becomes >, & becomes &. Critical for preventing XSS attacks and displaying code in web pages.
Hex Encoding
Represents each byte as a two-character hexadecimal number. Used in cryptography, binary inspection, and low-level debugging.
ROT13
A simple Caesar cipher that shifts letters by 13 positions. Used for hiding spoilers, puzzle solutions, and light obfuscation (not security!).
How to Use Our Encode/Decode Tool
- Paste your text in the input area
- Select operation — Encode or Decode
- Choose encoding type — Base64, URL, HTML, Hex, Base32, or ROT13
- Auto-detect — when decoding, the tool can guess the input format
- Copy the result with one click
Common Developer Use Cases
| Scenario | Encoding |
|---|---|
| Embed an image in CSS/HTML | Base64 encode |
| Pass special chars in a URL | URL encode |
Display <script> in a blog post | HTML encode |
| Inspect binary file contents | Hex encode |
| Debug a JWT payload | Base64 decode |
| Sanitize user input before rendering | HTML encode |
Security Note
Encoding is NOT encryption. Base64, URL encoding, and Hex are reversible by design — they provide zero security. Never rely on encoding to protect sensitive data. Use proper encryption (AES, RSA) for security.
Why Use Our Tool
- 6 encoding types in one tool — Base64, URL, HTML, Hex, Base32, ROT13
- Auto-detect — the tool identifies the encoding format for you
- Bidirectional — encode and decode in the same interface
- Instant results — no page reload
- Copy to clipboard — one click
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