Developer Glossary

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ACID stub Atomicity, Consistency, Isolation, Durability , transaction guarantees of relational DBs.
API key stub Opaque secret used to authenticate a server-to-server API caller.
ASCII stub American Standard Code for Information Interchange , 7-bit character encoding.
AST stub Abstract Syntax Tree , tree representation of source code used by compilers and linters.

Base64 Binary-to-text encoding that represents arbitrary bytes as 64 printable ASCII characters.

Canonical URL stub The preferred URL for a piece of content, declared via `<link rel="canonical">`.
Canvas stub HTML `<canvas>` element , bitmap drawing surface driven by JavaScript.
Capture group Parenthesized sub-pattern in a regex whose match can be extracted or backreferenced.
Chroma subsampling stub Image compression trick that stores color at a lower resolution than luminance.
CORS Browser mechanism that relaxes the same-origin policy to allow controlled cross-domain HTTP requests.
CRLF stub Carriage Return + Line Feed (`\r\n`) , Windows-style line ending used in HTTP and email.
Cron expression Five-field schedule syntax (minute hour day month weekday) used to run recurring jobs on Unix.
CSRF stub Cross-Site Request Forgery , attack that tricks a logged-in user into submitting an action.
CSS Grid stub Two-dimensional CSS layout system that arranges items in rows and columns.
CSV Plaintext tabular format with comma-separated fields, one record per line.

Debounce stub Wrap a function so it only fires after a burst of calls has quieted for N ms.
DNS Hierarchical system that resolves human-readable domain names to IP addresses.
Docker Container platform that packages an app and its dependencies into a portable, isolated image.
DOM stub Document Object Model , tree of nodes representing an HTML or XML document in the browser.

Flexbox stub One-dimensional CSS layout system that distributes space along a single axis.

Git stub Distributed version control system that tracks content-addressed snapshots of a tree.
GraphQL Typed query language and runtime that lets API clients request exactly the fields they need.

Hex color Color written as hexadecimal RGB(A) values (e.g. #ff0000), the standard CSS color notation.
HMAC Keyed hash construction that proves both data integrity and the sender's identity.
hreflang stub Link-tag attribute that tells search engines which language+region variant to show.
HTTP stub HyperText Transfer Protocol , the request-response protocol powering the web.
HTTPS stub HTTP over TLS , encrypted variant of HTTP that prevents eavesdropping.

Idempotent stub Property of an operation that produces the same result whether called once or many times.
ISO 8601 International date/time format (YYYY-MM-DDTHH:MM:SSZ) that avoids locale-dependent ambiguity.

JSON Lightweight, text-based data format using key-value pairs and arrays to represent structured data.
JWT Compact, signed token format (header.payload.signature) used to carry authentication claims.

Lookahead Zero-width regex assertion that checks what follows a position without consuming those characters.

Markdown stub Lightweight plain-text format that converts to HTML, used for docs and READMEs.
MD5 128-bit hash function, cryptographically broken since 2004 but still used for non-adversarial checksums.
Minifier Tool that strips whitespace and shortens code without changing its behavior, to reduce transfer size.

OAuth 2.0 stub Authorization framework that issues access tokens on behalf of a user.
Open Graph stub Meta-tag protocol from Facebook that controls how URLs appear when shared.

Primary key stub Column (or set of columns) that uniquely identifies each row in a table.
PWA stub Progressive Web App , installable web app with service-worker-powered offline support.

Redis In-memory data store used as a cache, queue, or rate limiter, with strings, hashes, sets, and sorted sets.
Regex Pattern-matching mini-language for finding, validating, or extracting text.
REST stub Representational State Transfer , API style using HTTP verbs on resource URLs.
robots.txt stub Root-level text file that tells crawlers which paths they may or may not index.

Service Worker stub Browser-side script that can intercept fetch requests , enables offline and push.
SHA-1 160-bit hash function, cryptographically broken since 2017 but still found in legacy systems.
SHA-256 256-bit hash from the SHA-2 family, the default modern checksum and password-adjacent hash function.
Source map stub File that maps compiled/minified code back to its original source for debugging.
SQL stub Structured Query Language , declarative language for relational databases.
SQLite stub Self-contained serverless SQL database stored in a single file.
sRGB Standard RGB color space that defines what a color's numeric values actually look like on screen.
SSH key stub Public/private keypair used for passwordless SSH and Git authentication.
Structured data stub Schema.org markup (JSON-LD) that makes a page understandable to search engines.

Throttle stub Wrap a function so it fires at most once per N ms regardless of how often it's called.
TLS stub Transport Layer Security , successor to SSL, the cryptographic layer under HTTPS.
TOML Minimal, explicitly typed config file format with `[section]` tables, used by Cargo and Python packaging.

Unicode Universal character standard assigning a unique code point to every character across the world's scripts.
Unix timestamp Count of seconds since 1970-01-01 00:00:00 UTC, the standard machine-readable absolute time.
URL encoding Percent-encoding scheme that makes reserved and non-ASCII characters safe inside a URL.
UTC Coordinated Universal Time, the atomic-clock time standard with zero offset that all time zones are defined relative to.
UTF-8 Variable-length byte encoding for Unicode, backward compatible with 7-bit ASCII.
UUID 128-bit identifier, usually random, written as 32 hex digits in 8-4-4-4-12 groups.

WebGL stub WebGL , GPU-accelerated 3D graphics API for browsers, based on OpenGL ES.
Webhook stub HTTP callback the server fires at a caller-provided URL when an event occurs.
WebSocket stub Persistent bidirectional TCP connection over a single HTTP-upgraded socket.

XML Tag-based markup format for structured data, validated by DTD/XSD schemas, used in configs and legacy APIs.
XSS stub Cross-Site Scripting , attack that injects attacker-controlled JS into a victim's page.

YAML Indentation-based, human-readable data format common in config files, a superset of JSON since YAML 1.2.