Encoders & Decoders
Encode and decode data for safe transmission across different systems. Essential tools for web development, API integration, and data security. Base64, URL encoding, HTML entities, and JSON string escaping — all processed locally in your browser for complete privacy.
Base64 Encoder
Encode text or binary data to Base64 and decode Base64 back to original format
URL Encoder
Encode special characters for safe URL transmission and decode URL-encoded strings
HTML Entities
Convert special characters to HTML entities and decode entities back to text
JSON Encoder
Escape strings for safe JSON inclusion and unescape JSON-encoded strings
What is Encoding?
Encoding transforms data into a different format for safe transmission, storage, or processing. Unlike encryption (which hides data), encoding converts data to a format that can pass through systems that might otherwise corrupt or misinterpret it.
For example, URLs can only contain certain characters. Special characters like spaces, ampersands, and non-ASCII characters must be encoded (spaces become %20, & becomes %26) to be transmitted correctly. Similarly, HTML special characters (<, >, &) need encoding to display literally instead of being interpreted as markup.
Why Encoding Matters
- Data Integrity: Ensure special characters don't break URLs, HTML, or JSON
- Security: Prevent XSS attacks by encoding user-supplied HTML content
- Compatibility: Transmit binary data through text-only channels (email, JSON)
- Interoperability: Share data between systems with different character set expectations
Types of Encoding We Support
- Base64: Converts binary data to ASCII text for embedding in documents, emails, or data URIs
- URL Encoding: Escapes special characters in URLs (percent-encoding)
- HTML Entities: Converts special characters to HTML entity references
- JSON Escaping: Escapes characters for safe inclusion in JSON strings
Understanding Encoding Types
Base64 Encoding
Base64 converts binary data into a text format using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). This allows binary data like images to be embedded directly in HTML, CSS, JSON, or email without corruption.
Use cases: Data URIs for embedding images, encoding file attachments in emails, storing binary data in JSON, and HTTP Basic Authentication credentials.
Try Base64 Encoder →URL Encoding
URLs can only contain a limited set of ASCII characters. Special characters, spaces, and non-ASCII characters must be percent-encoded — replaced with a percent sign followed by their hexadecimal value.
Use cases: Query parameters, form submissions, embedding special characters in paths, internationalized domain names (IDN).
Try URL Encoder →HTML Entities
HTML uses certain characters (<, >, &, ", ') as syntax. To display these literally, they must be encoded as entity references. This is also crucial for security — encoding user input prevents XSS (Cross-Site Scripting) attacks.
Use cases: Displaying code samples, preventing XSS, rendering special symbols (©, ™, ®), embedding user-generated content safely.
Try HTML Entities Encoder →JSON String Encoding
JSON strings have their own escape sequences. Quotes, backslashes, and control characters must be escaped to be valid inside JSON. This is essential when building JSON manually or embedding user input in API responses.
Use cases: Building JSON strings programmatically, escaping user input for API responses, preparing data for JavaScript inclusion.
Try JSON Encoder →Common Use Cases
Web Development
Web developers constantly encode and decode data. URL parameters need percent-encoding, user content needs HTML encoding for XSS prevention, and Base64 enables data URIs for embedding images directly in HTML or CSS.
- • Encode query parameters for AJAX requests
- • Create data URIs for inline images
- • Escape user input to prevent XSS
- • Debug encoded URLs and data
API Integration
APIs often require specific encoding for authentication (Basic Auth uses Base64), data transmission (JSON escaping), and URL construction. Decoding helps debug webhook payloads and API responses.
- • Create Basic Auth headers
- • Build OAuth request signatures
- • Decode webhook payloads
- • Debug encoded API parameters
Security
Proper encoding is a key security practice. HTML encoding prevents cross-site scripting (XSS). URL encoding prevents injection attacks. Understanding encoding helps security professionals audit applications for vulnerabilities.
- • Sanitize user input before display
- • Test for encoding-based vulnerabilities
- • Analyze potentially malicious payloads
- • Verify proper output encoding
Email & Data Transfer
Email systems were designed for text, but we often need to send binary attachments. Base64 encoding allows images, documents, and other files to be embedded in emails or transmitted through text-based protocols.
- • Encode email attachments
- • Embed images in HTML emails
- • Transmit binary data via text protocols
- • Store binary data in databases
Frequently Asked Questions
Is encoding the same as encryption?
No. Encoding transforms data to a different format but doesn't hide it — anyone can decode Base64 or URL-encoded text. Encryption uses a secret key to make data unreadable without that key. Use encoding for compatibility, encryption for security.
Why does Base64 make files larger?
Base64 uses 4 ASCII characters to represent every 3 bytes of original data, resulting in ~33% size increase. This tradeoff enables binary data to be transmitted through text-only channels. For large files, this overhead matters; for small images or tokens, it's acceptable.
When should I use URL encoding?
Use URL encoding whenever you include user input or special characters in URLs. Query parameters, form data, and any text that might contain spaces, ampersands, equals signs, or non-ASCII characters need encoding to be transmitted correctly.
How do I prevent XSS with encoding?
HTML-encode all user-supplied content before displaying it in HTML. Convert < to <, > to >, and & to &. This prevents attackers from injecting malicious scripts. Our HTML encoder does this automatically.
Start Encoding
Choose an encoder and transform your data instantly. Free, fast, and completely private.