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Encode / Decode Tool

Encode and decode text using Base64, URL encoding, HTML entities, and other common encoding schemes.

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Encode or decode your text string

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What is Encoding and Decoding?

Encoding transforms data from one format into another for safe transmission or storage. Unlike encryption, encoding is not designed for security, anyone can decode data without a secret key. The two most common encoding schemes are Base64 (for binary data) and URL encoding (for special characters in URLs). Base64 converts binary data into ASCII text using 64 printable characters (A-Z, a-z, 0-9, +, /). URL encoding replaces special characters with percent-encoded values (e.g., space becomes %20).

Our encode/decode tool supports both Base64 and URL encoding schemes. It runs entirely in your browser using JavaScript's built-in btoa(), atob(), encodeURIComponent(), and decodeURIComponent() functions. You can quickly switch between encoding and decoding modes to test data transformations or debug API payloads.

How to Use the Encoder/Decoder

Step-by-Step Guide

  1. 1. Select Encoding Type: Click the "base64" or "url" tab to choose which encoding scheme to use.
  2. 2. Enter Your Data: Paste your text into the input field. For Base64, you can enter multi-line text. For URL encoding, enter URL strings or query parameters.
  3. 3. Choose Operation: Click "Encode" to convert plain text into encoded format, or "Decode" to convert encoded data back to plain text.
  4. 4. View Result: The encoded or decoded output appears in the right panel. The operation type (Encoded/Decoded value) is labeled at the top.
  5. 5. Copy Output: Click the copy button in the result panel to copy the output to your clipboard for use elsewhere.

If you switch between Base64 and URL tabs, the results are cleared. The tool validates input before processing, decoding invalid Base64 or malformed URL-encoded strings will produce an error message.

When to Use Encoding

Base64 Use Cases

  • • Email Attachments: MIME emails use Base64 to encode binary attachments (images, PDFs) as text
  • • Data URIs: Embed images directly in HTML/CSS using Base64 (e.g., data:image/png;base64,...)
  • • API Payloads: Send binary data through JSON APIs that only accept text
  • • JWT Tokens: JSON Web Tokens use Base64 URL-safe encoding for header and payload sections
  • • Configuration Files: Store binary certificates or keys in text-based config files

URL Encoding Use Cases

  • • Query Parameters: Encode special characters in URL query strings (e.g., ?search=hello%20world)
  • • Form Submissions: application/x-www-form-urlencoded forms encode data with this scheme
  • • Sharing Links: Safely pass arbitrary text in URLs without breaking the URL structure
  • • API Requests: Encode path parameters or headers containing special characters
  • • OAuth Redirects: Encode callback URLs passed as parameters to OAuth providers

Why Encoding is Not Encryption

A common misconception is that Base64 encoding provides security. It does not. Encoding is reversible by design, anyone can decode Base64 or URL-encoded data without any secret key. Encoding improves compatibility and prevents data corruption during transmission, but it offers zero secrecy. If you need confidentiality, use encryption (AES, RSA) instead of encoding.

⚠️ Security Warning: Never store passwords or sensitive data in Base64 thinking it's secure. Base64 is trivially reversible and provides no protection against attackers.

Common Use Cases

  • ✓ Debugging APIs: Decode Base64-encoded API responses or JWT tokens to inspect their contents.
  • ✓ Testing Applications: Encode test data to simulate how APIs or systems handle encoded inputs.
  • ✓ Payload Analysis: Security researchers decode obfuscated payloads in scripts or network traffic.
  • ✓ Data Recovery: Decode corrupted or mangled encoded strings to recover the original data.
  • ✓ Learning & Education: Understand how encoding works by encoding and decoding sample text.

Technical Details

Base64 Encoding: Uses a 64-character alphabet (A-Z, a-z, 0-9, +, /) to represent binary data as ASCII text. Every 3 bytes (24 bits) of input are encoded as 4 Base64 characters. Padding (= symbols) is added if the input isn't a multiple of 3 bytes. The encoded output is ~33% larger than the original data.

URL Encoding (Percent Encoding): Replaces unsafe characters with a percent sign followed by two hexadecimal digits representing the character's ASCII code. For example, space becomes %20, @ becomes %40. This ensures URLs contain only safe ASCII characters and don't break URL parsing.