Vibulary
Menu
Appearance and language
Terms by topic · 61 guides

Technology & Testing

Learn the parts used to build the web and the tests that show whether they work well.

01 / Atlas

All Technology & Testing terms

Open a term for a simple meaning, an example, when to use it, how official it is, and its code name.

  1. 01 · Core

    Accessibility Testing

    Accessibility testing uses tools and people to check whether content and controls meet accessibility needs. It includes testing with keyboards and assistive technology.

  2. 02 · More detail

    Accessibility, Performance & Observability — Learning Bundle

    This learning bundle joins three quality fields. Accessibility checks who can use the product. Performance checks response speed and resource cost. Observability helps explain a running system. The bundle is not one standard quality metric.

  3. 03 · More detail

    Async Race Condition

    An async race happens when overlapping jobs finish in an unexpected order. An older result may overwrite a newer one.

  4. 04 · Core

    Build

    A Build turns source files and listed dependencies into checked output that can run, test, or deploy.

  5. 05 · More detail

    Client-side Rendering

    Client-side rendering (CSR) means the browser builds most of the app screen after JavaScript and the needed data arrive.

  6. 06 · More detail

    Component Test

    A component test places one interface part in a real rendering space. It gives the part controlled input and data, then checks its behavior.

  7. 07 · More detail

    Contract Testing

    Contract testing checks whether two systems that can deploy separately still exchange messages in the agreed format.

  8. 08 · Core

    Core Web Vitals

    Core Web Vitals is Google's set of real-user measures for page loading, response to input, and visual stability. The current measures are LCP, INP, and CLS.

  9. 09 · Core

    CSS

    CSS is a set of web rules that controls how document elements look and fit together. It can set color, spacing, layout, screen-size changes, and visual states.

  10. 10 · Core

    Data Fetching Lifecycle

    The data fetching lifecycle follows one read request. It moves through waiting to success or error. Success may contain data or be empty.

  11. 11 · Core

    Data Mutation

    A data mutation creates, changes, or removes server data. The screen tracks its pending and final result.

  12. 12 · Core

    Data Prefetching

    Data prefetching loads likely-needed data before its screen opens. A fresh cached result can make the next screen faster.

  13. 13 · Core

    DOM

    The Document Object Model (DOM) turns a document into a tree of objects called nodes. Programs use its standard tools to read and change the document.

  14. 14 · Core

    End-to-end Test

    An end-to-end (E2E) test follows a complete user or business journey through the assembled and deployed system.

  15. 15 · Core

    Error Boundary

    An error boundary catches a screen crash inside one part of a component tree. It shows a safe replacement there.

  16. 16 · More detail

    Flaky Test

    A Flaky Test can pass or fail without a code change. Timing, order, shared state, randomness, or outside systems often cause it.

  17. 17 · Core

    Frontend State Management

    Frontend state management decides what a screen remembers, where that data lives, and what may change it.

  18. 18 · Core

    Frontend Web Stack — Learning Bundle

    This learning bundle connects three browser technologies. HTML gives a document meaning. CSS controls how it looks. JavaScript or TypeScript adds behavior. This systems view is not one standard technology.

  19. 19 · Core

    HTML

    HTML is the standard markup language that gives a web page its parts and meaning. It tells the browser what is a heading, link, image, form, and more.

  20. 20 · More detail

    Hydration

    Hydration connects browser behavior and state to HTML that a server or build already made. This turns chosen parts of the page into interactive controls.

  21. 21 · Core

    Integration Test

    An integration test checks whether two or more parts of a system work together through their real connection points.

  22. 22 · Core

    JavaScript

    JavaScript is a programming language based on the ECMAScript standard. It is often used to make websites and other programs respond to actions and change over time.

  23. 23 · Core

    Lint

    Lint checks code without running it. It finds likely bugs, unsafe patterns, style issues, and broken project rules.

  24. 24 · More detail

    Load Testing

    Load testing checks a system's speed and reliability under planned traffic. The plan sets the number and pattern of users, requests, or jobs.

  25. 25 · More detail

    Local-First Sync

    Local-first sync keeps a working copy on the device. People can read and write offline, then join changes with copies on other devices.

  26. 26 · Core

    Markdown

    Markdown formats plain text with small marks. Those marks create headings, lists, links, and code blocks.

  27. 27 · More detail

    Module Bundler

    A module bundler follows the links between code modules and makes files ready to deploy. It often splits, changes, and improves those files.

  28. 28 · More detail

    Next.js

    Next.js is a framework built on React. It adds routing, server and browser rendering, data loading, asset optimization, and deployment rules.

  29. 29 · Core

    npm

    npm is a JavaScript package registry and command-line tool. It installs, lists, and publishes packages, and runs project scripts.

  30. 30 · More detail

    Observability Signals

    Observability signals are evidence a system sends about its own behavior. Common signals are traces, metrics, logs, and baggage, which carries small context between services.

  31. 31 · Core

    Optimistic UI

    Optimistic UI shows the expected result before the server confirms it. Failure restores the old result and explains what happened.

  32. 32 · Core

    Package Manager

    A package manager finds, installs, records, updates, and publishes software packages and the packages they depend on.

  33. 33 · More detail

    Performance Budget

    A performance budget is a limit set before work begins for file size, timing, or user experience. It helps guide design and code choices.

  34. 34 · Core

    Polling

    Polling repeats a read on a timer to check for change. The interval can adapt, pause, or stop when work finishes.

  35. 35 · Core

    Python

    Python is a general-purpose programming language with readable code. Its tools cover web services, automation, data, and machine learning.

  36. 36 · More detail

    Query Invalidation

    Query invalidation marks matching cached data as old. Related data that is on screen can then refresh in the background.

  37. 37 · Core

    React

    React is a JavaScript library for component-based interfaces. Data, props, or state changes can update the screen. It is not ReAct.

  38. 38 · Core

    Regression Test

    A Regression Test checks that a later code change did not break behavior that worked before.

  39. 39 · Core

    Request Cancellation

    Request cancellation says that unfinished client work is no longer needed. Supported APIs receive an abort signal.

  40. 40 · More detail

    Request Deduplication

    Request deduplication lets matching callers share one request that is already running. Each caller receives the same result.

  41. 41 · Core

    Search Engine Optimization

    SEO helps useful public pages get found and understood. It also keeps them easy to crawl and index.

  42. 42 · More detail

    Security Testing

    Security testing uses a clear plan to check security rules and find weaknesses attackers could use. It covers design, code, settings, and system operation.

  43. 43 · Core

    Semantic Versioning

    Semantic Versioning (SemVer) uses MAJOR.MINOR.PATCH numbers to show how a public API changed. It also sets rules for prerelease and build labels.

  44. 44 · Core

    Server State

    Server state is remote data that the server owns. The screen keeps a copy and must refresh it.

  45. 45 · More detail

    Server-side Rendering

    Server-side rendering (SSR) makes HTML on a server for each request, then sends the ready page to the browser. Client behavior may be attached later.

  46. 46 · More detail

    shadcn/ui

    shadcn/ui gives applications editable UI component source. It often combines accessible base controls with Tailwind CSS.

  47. 47 · Core

    Smoke Test

    A Smoke Test is a small, fast check set. It shows whether a build can receive deeper tests or use.

  48. 48 · More detail

    Stale-While-Revalidate

    Stale-while-revalidate may show an allowed stale cache at once while checking for a fresh response in the background.

  49. 49 · Core

    Static Site Generation

    Static site generation (SSG) makes each route's HTML before visitors ask for it, usually during a build. The server can then send ready-made files.

  50. 50 · Core

    Tailwind CSS

    Tailwind CSS is a utility-first CSS framework. Small classes in HTML apply shared design values and variants.

  51. 51 · Core

    Terminal

    A Terminal is a text window for a command shell and tools. It can inspect files, run commands, and automate work.

  52. 52 · Core

    Test Case

    A Test Case checks one behavior or risk. It names the starting setup, action, and expected result.

  53. 53 · More detail

    Test Coverage

    Test Coverage shows which code, needs, states, or risks tests check. A percentage is only one rough sign.

  54. 54 · More detail

    Test Data and Fixture

    Test Data and Fixtures are known inputs and setup steps. They put the system in the same state for each test.

  55. 55 · More detail

    Test Double

    A Test Double stands in for a real system part. Stubs, fakes, spies, and mocks give control or visibility.

  56. 56 · More detail

    Test-driven Development

    Test-driven development (TDD) repeats three steps. Write a small failing test. Write the least code that passes. Then clean the code without changing how it works.

  57. 57 · More detail

    Transpiler

    A transpiler is a compiler that changes source code from one language version or syntax into other source code.

  58. 58 · Core

    Unit Test

    A unit test checks one small piece of software by itself. Slow or unreliable outside systems are kept out of the test.

  59. 59 · Core

    Unit, Integration & End-to-End Testing — Learning Bundle

    This learning bundle compares three test scopes. Unit tests check logic by itself. Integration tests check boundaries between parts. End-to-end tests run through the system people use. The bundle is not one standard test level.

  60. 60 · More detail

    Visual Regression Test

    A visual regression test compares today's rendered image with an approved reference image under the same browser conditions.

  61. 61 · Core

    Vue

    Vue is a JavaScript framework for component interfaces. Its templates describe the screen, and reactive data updates it.