What is JWT?

JSON Web Token (JWT) is an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. Widely used for authentication, SSO, and API security. A JWT consists of three parts: Header, Payload, and Signature, separated by dots.

How to Decode a JWT Token

Paste your token and click Decode. Our tool extracts the Base64-encoded Header and Payload, displaying them as readable JSON. Note: Decoding only reveals contents — it does not verify the signature, which requires the secret key.

JWT Security Tips

• Never share JWT tokens with untrusted parties
• Always validate tokens on the server side
• Use HTTPS to prevent token interception
• Set short expiration times (e.g., 15 minutes)
• Never store sensitive data in the payload — it is only base64-encoded, not encrypted

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. Commonly used to embed images in HTML/CSS, encode email attachments, and transmit binary data over text-based protocols. Each Base64 digit represents 6 bits of data, resulting in ~33% size overhead.

Common Use Cases

• Embedding images directly in HTML or CSS as data URIs
• Encoding binary attachments for email (MIME)
• Storing binary data in JSON or XML documents
• Transmitting data in URL-safe formats

What is URL Encoding?

URL encoding (percent-encoding) converts characters into a format safely transmitted over the internet. Certain characters have special meanings in URLs — spaces, ampersands (&), question marks. URL encoding replaces unsafe characters with a percent sign (%) followed by their hexadecimal value.

Why Use a URL Encoder/Decoder?

• Preparing query string parameters for API requests
• Debugging encoded URLs from web applications
• Encoding special characters in form submissions
• Decoding URLs for readability and analysis

What is a Unix Timestamp?

A Unix timestamp is the number of seconds since January 1, 1970 (UTC), excluding leap seconds. Widely used in programming for representing dates in a simple numeric format — timezone-independent, ideal for storing and transmitting date information across systems.

When to Use a Timestamp Converter

• Debugging database records that store timestamps
• Interpreting API response timestamps
• Converting between timestamps and human-readable dates
• Working with expiration times in authentication tokens

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122. UUID v4 is randomly generated with ~5.3×10³⁶ possible values — making duplicates virtually impossible. Ideal for database primary keys, session identifiers, and transaction IDs.

Why Use Our UUID Generator?

• Generate 1–100 UUID v4 identifiers instantly
• 100% client-side generation with cryptographically secure random numbers
• One-click copy for developer workflows
• No server calls, no tracking, no limits

What is a Color Converter?

A color converter transforms color values between different models: HEX (hexadecimal), RGB (Red-Green-Blue), and HSL (Hue-Saturation-Lightness). Each model serves different purposes — HEX is common in web design, RGB for screen display, and HSL for intuitive color manipulation.

When to Use a Color Converter

• Converting design tokens between CSS color formats
• Matching colors from design tools (Figma, Sketch) to code
• Understanding color components for UI customization
• Quickly previewing how a color looks before using it

What is Number Base Conversion?

Number base conversion changes a number from one base (radix) to another. The most common bases are decimal (10), hexadecimal (16), binary (2), and octal (8). Understanding number bases is fundamental in computer science, digital electronics, and low-level programming.

Common Use Cases

• Converting between binary and hexadecimal for memory addresses
• Interpreting color codes (HEX to decimal)
• Working with permission masks (e.g., chmod octal values)
• Debugging network protocols and binary data

What is Regular Expression?

A regular expression (regex) is a sequence of characters defining a search pattern. Powerful for pattern matching, text extraction, and validation. Used in programming languages, text editors, and command-line tools for searching and manipulating text based on patterns rather than exact matches.

Common Regex Use Cases

• Validating email addresses, phone numbers, and URLs
• Extracting data from logs and structured text
• Search and replace operations in code editors
• Form input validation in web applications
• Parsing CSV, JSON, and other data formats

What is Markdown?

Markdown is a lightweight markup language for creating formatted text using plain-text syntax. Created by John Gruber in 2004, it is designed to be easy to read and write, and converts to HTML. Widely used for documentation, README files, forum posts, and static site generation.

Common Markdown Uses

• Writing README files for GitHub and GitLab repositories
• Creating documentation for open-source projects
• Writing blog posts with static site generators
• Formatting messages on Reddit, Discord, and Slack
• Taking notes with tools like Obsidian and Notion

Supported Syntax

Headings (#–######), bold (**text**), italic (*text*), inline code (`code`), code blocks (```), lists (- / 1.), links ([text](url)), images (), blockquotes (>), horizontal rules (---), and paragraphs. All rendering is client-side.

What is a Cryptographic Hash?

A cryptographic hash function produces a fixed-size string from an input. One-way — you cannot reverse a hash to get the original input. Even a tiny change produces a completely different hash (avalanche effect). Different algorithms: MD5 (128-bit), SHA-1 (160-bit), SHA-256 (256-bit), SHA-512 (512-bit).

Common Hash Use Cases

• Verifying file integrity (checksums)
• Storing passwords securely (with salting)
• Digital signatures and certificates
• Data deduplication and fingerprinting

Security Note

MD5 and SHA-1 are considered cryptographically broken. Use SHA-256 or SHA-512 for security-critical purposes. All hashing is performed in your browser using the Web Crypto API — your data never leaves your device.

What Makes a Strong Password?

A strong password is long, random, and contains a mix of character types. Strength is measured by entropy — the number of possible combinations. Each additional character exponentially increases the difficulty of brute-force attacks. A 16-character password with all character types has over 10²⁸ possible combinations.

Password Security Tips

• Use a unique password for every website and service
• Make passwords at least 12–16 characters long
• Use a password manager to store generated passwords
• Enable two-factor authentication (2FA) when available
• Never reuse passwords across important accounts