Tech glossary
37 terms explained with care: definition, how it works, when to use it, and links to related Genfy generators.
🔑 API Key An API Key is a unique, cryptographically strong token that identifies an authorized client of an API. Unlike a JWT, it doesn't contain information (claims) about the user: it only authenticates that the caller has permission to use the API. 🎭 ASCII Art ASCII Art is the technique of creating visual images using only the 95 printable characters of the ASCII standard (letters, numbers, symbols). It emerged from technical limitations of 1970s printers and today is part of the retro aesthetic of hacker and developer culture. 🖥️ Aspect Ratio Aspect Ratio is the mathematical proportion between the width and height of an image, video or screen. It's expressed as two numbers separated by a colon (e.g., 16:9, 4:3, 1:1), defining its rectangular shape and visual experience. It's fundamental in design, photography, video and web development. 🔤 Base64 Base64 is an encoding scheme that transforms binary data into a sequence of printable ASCII characters using a 64-symbol alphabet. It's widely used to transmit binary files through text-based protocols like email, JSON, or URLs. 🛡️ Bcrypt Bcrypt is a password hashing algorithm based on the Blowfish cipher, designed in 1999 by Niels Provos and David Mazières. Its key feature is a configurable cost factor that makes it intentionally slow, protecting against brute-force attacks even if the database is compromised. 🧑💼 Buyer Persona A Buyer Persona is a semi-fictional, detailed representation of a product or service's ideal customer. It's built from real demographic data, observed behaviors, motivations and goals, combined with informed assumptions about needs and pain points. ⏰ Cron Cron is a Unix/Linux task scheduling system and its five-field syntax (minute, hour, day of month, month, day of week) for defining when to execute commands automatically. 📐 CSS clamp() clamp() is a CSS function that returns a value bounded between a minimum and maximum, based on a preferred value that scales. It's the cornerstone of modern fluid typography. 🟦 CSS Grid CSS Grid is a two-dimensional layout system that allows dividing a page into rows and columns, creating named areas and aligning elements precisely. It's the modern standard for complex layouts. 📊 CSV CSV (Comma-Separated Values) is a plain text file format for tabular data. Each line represents a row and values are separated by commas (or semicolons in regions using comma as decimal separator). 🖼️ Favicon A favicon is the small icon displayed in your browser tab, next to your site's title. It also appears in bookmarks, history, and mobile search results. It's a fundamental part of web visual identity. 🔮 GraphQL GraphQL is a query language and runtime for APIs developed by Facebook in 2012 and open-sourced in 2015. Unlike REST, where each endpoint returns a fixed structure, GraphQL allows the client to specify exactly which fields it needs in a single query, reducing over-fetching, under-fetching, and multiple requests. 🎨 Hex color Hexadecimal format (#RRGGBB) is the most common notation for specifying colors in CSS, HTML, and digital design. Each color is represented with 6 hexadecimal digits (base 16: 0-9, A-F), divided into three pairs encoding the intensity of red, green, and blue (RGB) in values from 0 (00) to 255 (FF). ✍️ HMAC HMAC (Hash-based Message Authentication Code) is a cryptographic mechanism that combines a hash function (like SHA-256) with a shared secret key to generate an authentication code. It guarantees that a message wasn't altered and comes from who it claims to be. 🚦 HTTP Status Codes HTTP status codes are three-digit numbers that the server sends in the response to each HTTP request. They indicate whether the request was successful, requires additional action, failed due to client error, or encountered a server problem. 🌐 IPv4 IPv4 (Internet Protocol version 4) is the predominant IP address format on the Internet, with 32 bits represented in dotted decimal notation (example: 192.168.1.1). It allows ~4.3 billion unique addresses, a space practically exhausted since 2011. 📐 JSON Schema JSON Schema is a formal specification that describes the expected structure of a JSON object: which properties exist, what data types they contain, which are required, and what constraints they must meet. It's widely used to validate requests and responses in REST APIs, generate automatic documentation, and ensure contracts between frontend and backend. 🎟️ JWT JWT (JSON Web Token) is an open standard (RFC 7519) for securely transmitting information between two parties as a digitally signed JSON object. It's the most used format for authentication in modern APIs, single sign-on (SSO), and authorization in distributed systems. 📝 Lorem Ipsum Lorem Ipsum is a pseudo-classical Latin filler text derived from 'De finibus bonorum et malorum' by Cicero (45 BC). It's been used since the 16th century as typographic placeholder to visualize design, layout, and fonts without real content distracting. 📚 Lorem Ipsum Origin Lorem Ipsum comes from the philosophical treatise De Finibus Bonorum et Malorum (On the Ends of Good and Evil) written by Marcus Tullius Cicero in 45 BC. A 16th-century typographer scrambled and adapted it as filler text, becoming the graphic design standard for over 500 years. 💳 Luhn Algorithm The Luhn Algorithm (also called Mod 10) is a simple checksum formula that detects typographical errors in identification numbers. Created by Hans Peter Luhn in 1954, it's used in credit cards, IMEI, account numbers and other codes to validate they haven't been accidentally altered. 🔌 MAC Address A MAC (Media Access Control) address is a unique 48-bit identifier assigned to each physical network interface. The first 24 bits (OUI) identify the manufacturer, the last 24 the specific device. It operates at layer 2 of the OSI model. 📄 Markdown Markdown is a minimalist markup language that converts plain text with simple syntax into valid HTML. Created in 2004 by John Gruber and Aaron Swartz, today it's the de facto standard for technical documentation, READMEs and forums. #️⃣ MD5 MD5 (Message Digest Algorithm 5) is a cryptographic hash function that produces a 128-bit value (32 hexadecimal characters) from any input. While widely used for file integrity verification and password storage, it is now considered cryptographically broken for security purposes. 📻 Morse Code Morse Code is a communication system that represents letters and numbers through combinations of short (dots) and long (dashes) signals. Created by Samuel Morse in the 1830s, it revolutionized telecommunications by enabling long-distance message transmission via telegraph. 📏 px, rem, em px, rem, and em are CSS measurement units for defining font sizes, spacing, and dimensions. px is absolute (screen pixels), rem is relative to the root font size, and em is relative to the parent element's font size. 📱 QR Code A QR code (Quick Response) is a two-dimensional matrix of black and white modules that encodes data optically. It can store up to 2,953 bytes and uses Reed-Solomon error correction at 4 levels, enabling reading even with up to 30% damage. 🔄 REST API REST (Representational State Transfer) is an architectural style for designing APIs over HTTP, based on identifiable resources via URLs, standard methods (GET, POST, PUT, DELETE), and representations (JSON, XML). Created by Roy Fielding in 2000, it's the predominant standard for web APIs due to its simplicity, cacheability, and compatibility with existing HTTP infrastructure. 🧂 Salt (cryptography) In cryptography, a salt is a unique random string concatenated to a password before applying a hash function. Its purpose: ensure two users with the same password generate different hashes, making rainbow table attacks useless. 🔒 SHA-256 SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hash function that produces a 256-bit value from any input. It's part of the SHA-2 family designed by the NSA and is the current standard for data integrity, digital signatures, SSL certificates, and blockchain. 📦 SKU SKU (Stock Keeping Unit) is an internal alphanumeric code that uniquely identifies each product in your inventory. Unlike universal barcodes (UPC/EAN), you define SKUs according to your business needs. 🔗 Slug (URL) A slug is the final part of a URL that identifies a resource in readable form: lowercase text, no accents or spaces, with words separated by hyphens. Example: 'what-is-a-url-slug'. 📈 SWOT Analysis SWOT Analysis (Strengths, Weaknesses, Opportunities, Threats) is a strategic planning framework that evaluates internal and external factors of a project, product, or company. It organizes information into four quadrants to identify competitive advantages and risks. 🕵️ User-Agent The User-Agent is an HTTP header sent by every client (browser, mobile app, bot) to identify itself to the server. It contains information about the software, version, rendering engine and operating system. 🆔 UUID UUID (Universally Unique Identifier) is a 128-bit identifier designed to be unique without central coordination. With 5.3 × 10^36 possible combinations, the collision probability is so low that you can generate millions of UUIDs per second for centuries without duplicates. ♿ WCAG WCAG (Web Content Accessibility Guidelines) are the W3C's web accessibility guidelines, the international standard that defines how to make web content accessible to people with disabilities. 📜 YAML YAML (YAML Ain't Markup Language) is a data serialization format designed to be human-friendly. It relies on significant indentation and is the standard in configuration files for Docker, Kubernetes, GitHub Actions and Ansible.