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An open dictionary for product builders
Tech Terms, in human.
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All terms 283
Product001
A/B test
An experiment that compares randomly assigned groups exposed to different variants.
Security002
Access token
A credential a client presents to access protected resources within granted permissions and a limited lifetime.
Product003
Accessibility
Designing and building so people with diverse abilities can perceive and use a product.
Data004
ACID
Four transaction properties: atomicity, consistency, isolation, and durability.
AI005
AI agent
A system that observes a situation and selects actions toward a goal, sometimes using models and tools.
Web006
Ajax
A technique for exchanging data with a server and updating part of a page without a full page reload.
Code007
Algorithm
A sequence of steps for solving a problem or performing a task.
Web008
API
A defined way for one piece of software to request capabilities or data from another.
Web009
API-driven component
A UI component whose displayed data or behavior is supplied through an API, directly or through a data-loading layer.
Code010
Array
An ordered JavaScript collection whose elements can be accessed with zero-based indexes.
AI011
Artificial intelligence
A broad field of building systems that perform tasks associated with intelligence.
Tools012
Assertion
A check that states an expected condition and reports a failure when it is not met.
Web013
Asset
A resource used by an application, such as an image, stylesheet, script, font, or media file.
Code014
async function
A JavaScript function declared with async that always returns a promise and can use await to pause its own execution for a result.
Code015
Asynchronous
Describes work whose result can arrive later without requiring the caller to block until it completes.
AI016
Attention
A mechanism that computes weighted combinations of information according to its relevance.
Security017
Authentication
Checking that someone or something is who it claims to be.
Security018
Authorization
Checking whether an identity is allowed to perform an action or access a resource.
Tools019
Babel
A JavaScript compiler toolchain that can transform newer syntax and JSX into JavaScript suitable for configured target environments.
Tools020
Babel preset
A reusable bundle of Babel plugins and configuration for a particular transformation goal.
Web021
Backend
The server-side part of an application that handles work such as business rules, data access, and authorization.
Code022
Backslash
The character \ used in JavaScript strings to introduce escape sequences and in some systems as a path separator.
Cloud023
Backup
A separate copy of data kept so it can be recovered after loss or damage.
Networks024
Bandwidth
The data-carrying capacity of a connection over time.
Tools025
Behavior-driven style
An approach to describing software behavior through concrete scenarios and expected outcomes, often written as Given, When, Then.
Code026
Big O
Notation describing an upper bound on how resource use grows as input size grows.
Basics027
Binary
A number system that uses just two digits: 0 and 1.
Basics028
Bit
The smallest unit of digital information, with a value of either 0 or 1.
Code029
Boilerplate
Repetitive setup or structural code needed before the code specific to a task can do its work.
Code030
Boolean
A data type with two values, usually called true and false.
Tools031
Bootstrap
A frontend toolkit with styles, layout utilities, and components for building responsive interfaces.
Tools032
Branch
A movable reference in version control that lets work develop along a separate line.
Tools033
Browser console
A developer-tools panel for viewing messages and evaluating JavaScript in the context of a web page.
Basics034
Byte
A group of eight bits, commonly used to measure data size.
Basics035
Cache
A store of reusable results or data that can make future access faster.
Code036
Callback function
A function supplied to other code so that code can invoke it when appropriate.
Web037
Callback prop
A function passed as a React prop so a child can notify its parent or request an action.
Cloud038
CDN
A distributed network of servers that delivers content from locations closer to users, often with caching.
Code039
Chaining
Connecting operations so a returned value or promise becomes the starting point for the next operation.
Web040
Child component
A component rendered directly inside another component in the UI tree, often receiving data or callbacks through props.
Tools041
Claude Code
Anthropic's agentic coding tool that can inspect project files, propose and make changes, run commands, and work with development tools.
Tools042
CLI
An interface controlled by typing commands rather than primarily clicking visual controls.
Networks043
Client
A program or device that requests a resource or service from a server.
Cloud044
Cloud computing
Using computing resources provided over a network, often on demand.
Tools045
Code review
Examining a proposed code change for correctness, clarity, and other project requirements.
Tools046
Codebase
The collection of source code and related project files that make up a software system or maintained project.
Tools047
Commit
A recorded snapshot in version history with metadata and a message.
Code048
Compiler
A program that translates source code into another form, often machine code.
Code049
Concurrency
Organizing multiple tasks so they can make progress during overlapping periods.
Code050
Conditional
Code that chooses what to do based on whether a condition is true.
Code051
const
A JavaScript declaration for a block-scoped binding that cannot be reassigned after initialization.
Code052
Constructor
A function or class method used to initialize an object when an instance is created.
Cloud053
Container
An isolated execution environment that packages an application with needed user-space dependencies.
Cloud054
Container image
A packaged filesystem and metadata used as a template for containers.
Security055
Content Security Policy
Browser policy rules that restrict permitted resource loading and certain execution behaviors.
Web056
Content-Type
An HTTP header that identifies the media type of the associated request or response body.
AI057
Context window
The maximum sequence of tokens a model can consider in a given interaction.
Cloud058
Continuous delivery
Keeping software ready to release through an automated, repeatable pipeline.
Cloud059
Continuous integration
Frequently integrating code changes and checking them with automated builds or tests.
Web060
Cookie
A small piece of data a browser stores for a site and may send with matching requests.
Web061
CORS
Browser-enforced rules that let a server indicate which other origins may read its responses.
Code062
Coupling
The degree to which parts of a system depend on each other's details, behavior, or structure.
Basics063
CPU
The main processor that executes a computer's instructions.
Cloud064
Cron job
A task scheduled to run automatically at specified times using cron or a cron-compatible scheduler.
Security065
Cross-site request forgery
An attack that causes a browser to send an unwanted request using a victim's credentials.
Security066
Cross-site scripting
A vulnerability where attacker-controlled content executes as script in a user's browser.
Data067
CRUD
The four basic operations for managing stored data: create, read, update, and delete.
Web068
CSS
The stylesheet language used to control the presentation and layout of HTML and other supported documents.
Web069
CSS selector
A pattern that identifies which document elements a CSS rule should apply to.
Tools070
curl
A command-line tool for transferring data using URLs, commonly used to inspect and call HTTP endpoints.
Code071
Data structure
A way of organizing data so particular operations are convenient or efficient.
Code072
Data type
A classification that describes what kind of value something is and which operations make sense.
Data073
Database
An organized collection of data managed so applications can store, retrieve, and update information.
Data074
Database index
An additional structure that helps a database locate certain data efficiently.
Tools075
Debugging
Finding and understanding the cause of unintended software behavior.
Code076
Decoupling
Reducing unnecessary dependencies so parts can change, be tested, or be replaced with less impact on each other.
AI077
Deep learning
Machine learning using neural networks with multiple layers of representation.
Tools078
Dependency
Software or another component that your project relies on.
Cloud079
Deployment
Making a version of software available in its target environment.
Code080
Design pattern
A named, reusable approach to a recurring design problem, adapted to a particular context rather than pasted as finished code.
Web081
div
A generic HTML container with no special semantic meaning, used to group content for styling or scripting.
Networks082
DNS
A distributed system that maps domain names to records such as IP addresses.
Cloud083
Docker
A platform and set of tools for building and running container images.
Web084
DOM
The browser's object representation of a document, with nodes that scripts can inspect and change.
AI085
Embedding
A numerical representation that places items in a space where useful relationships can be compared.
Basics086
Encoding
A set of rules for representing information in a particular format.
Security087
Encryption
Transforming readable data into a form that requires appropriate key material to recover.
Web088
Endpoint
An addressable point where an API offers an operation; in HTTP APIs it is commonly identified by a method and URL.
Tools089
Environment variable
A named value provided to a process through its execution environment.
Code090
ES6
The 2015 edition of the ECMAScript standard that added features including let, const, arrow functions, classes, and modules.
Data091
ETL
A process that extracts data, transforms it, and loads it into a destination.
AI092
Evaluation
Measuring a model or system's performance against defined tasks and criteria.
Code093
Exception
A signal that normal execution cannot continue and needs an error-handling path.
Code094
Factory Pattern
A creational design approach that puts object creation behind a function or abstraction so callers need not choose or construct concrete implementations directly.
Cloud095
Failover
Switching work or traffic from a failed or unhealthy component to a healthy alternative, automatically or manually.
Web096
Fetch API
A browser API, also available in some other runtimes, for making requests and handling responses using promises.
AI097
Fine-tuning
Further training an existing model on additional data for a particular purpose.
Web098
Flux
An application architecture associated with React that organizes updates through a one-way cycle of actions, a dispatcher, stores, and views.
Data099
Foreign key
A constraint that links values in one table to valid referenced values in another.
Product100
Forward deployed engineer
A customer-facing engineer who works closely with customer teams to adapt, integrate, and deploy a company's technology into useful production workflows.
Web101
Framework
A reusable structure that supplies conventions and coordinates parts of an application, calling your code at defined points.
Web102
Frontend
The part of an application users interact with, including its interface and client-side behavior.
Code103
Function
A callable piece of code that can receive inputs, perform work, and return a value.
Code104
Function argument
An actual value or expression supplied when a function is called.
Code105
Function parameter
A named input in a function definition that receives a value when the function is called.
AI106
Generative AI
AI systems that produce new content such as text, images, audio, or code.
Web107
GET request
An HTTP request asking for a representation of a resource, such as a page or collection of terms.
Tools108
Git
A distributed version-control system that records changes and helps people work on code together.
Tools109
GitHub Pages
GitHub's hosting service for publishing static websites from repository content or build artifacts.
Basics110
GPU
A processor designed to perform many similar calculations in parallel.
Tools111
GUI
An interface that uses visual elements such as windows, icons, and buttons.
AI112
Hallucination
Generated output that is unsupported, false, or inconsistent with the available information.
Code113
Hard-coding
Embedding a fixed value directly in code instead of obtaining it from configuration, input, or another data source.
Tools114
Harness
Surrounding infrastructure that runs and controls a program, test, or AI agent, providing inputs, tools, execution rules, and result collection.
Security115
Hashing
Mapping input to a fixed-size output; cryptographic hashes are designed to resist certain attacks.
Tools116
Headless
Describes software operating without its usual visible graphical interface, or a system whose presentation layer is separated from its core.
Basics117
Hexadecimal
A number system with sixteen digits: 0–9 and A–F.
Code118
Hoisting
The name for declaration behaviors that can make bindings affect a scope before execution reaches their written declaration.
Web119
HTML
The markup language that describes the structure and meaning of web content using elements such as headings, links, and forms.
Web120
HTTP
An application-level request-response protocol used to exchange representations and metadata between clients and servers.
Security121
HttpOnly cookie
A cookie marked HttpOnly so browser JavaScript cannot read or change it through APIs such as document.cookie.
Web122
HTTPS
HTTP carried over a connection protected by TLS.
Basics123
I/O
Moving data into or out of a program or system, such as reading a file or communicating over a network.
Tools124
IDE
An application combining tools for writing, running, and inspecting code.
Code125
Immutable
Unable to change after creation, or deliberately treated as unchangeable so updates produce new values instead.
AI126
Inference
Using a model to produce an output from new input.
Web127
Initial state
The state value an application or component starts with before its later updates.
Tools128
Integration test
A test that checks whether multiple parts work together correctly across a chosen boundary.
Code129
Interface
A defined boundary through which people or software interact with a system, specifying the available operations or information.
Code130
Interpreter
A program that carries out instructions from code or an intermediate representation.
Networks131
IP address
An address used to identify an interface or destination for IP communication.
Product132
Iteration
A repeated cycle of trying, learning, and improving.
Web133
JavaScript
A programming language used for web interactions and many server, desktop, and tooling tasks.
Tools134
Jest
A JavaScript testing framework with a test runner, assertions, mocking utilities, and coverage support.
Web135
jQuery
A JavaScript library that offers concise DOM selection, manipulation, events, and Ajax utilities.
Web136
JSON
A text format for structured data using objects, arrays, strings, numbers, booleans, and null.
Web137
JSX
A JavaScript syntax extension for describing UI with HTML-like markup that tooling transforms into JavaScript element creation.
Security138
JWT
A compact format for carrying claims, such as a user ID, in a token that can be signed or encrypted.
Basics139
Kernel
The core of an operating system that manages resources such as memory and devices.
Product140
KPI
A chosen measure used to track progress toward an important objective.
AI141
Large language model
A large model trained on language-related data to predict or generate token sequences.
Networks142
Latency
The time delay between an action and a relevant response.
Web143
Leaf component
A component at the end of a component hierarchy that does not render other custom components below it.
Security144
Least privilege
Giving an identity only the access needed to perform its required tasks.
Code145
let
A JavaScript declaration for a block-scoped variable whose value can be reassigned.
Web146
Library
Reusable code that an application calls to perform particular tasks through a defined interface.
Basics147
Linux
An operating-system kernel whose name also commonly refers to distributions that combine it with system tools and software.
Cloud148
Load balancer
A component that distributes incoming traffic across available backends.
Networks149
Long polling
A technique where a client sends a request that the server keeps open until new data is available or a timeout occurs.
Code150
Loop
Code that repeats while a condition holds or for items in a collection.
AI151
Machine learning
Methods that learn patterns from data to make predictions or decisions.
Basics152
macOS
Apple's operating system for Mac computers, providing the desktop environment and services that applications use.
Tools153
Merge
Combining changes from different development histories.
Code154
Method
A function associated with an object, usually accessed through one of its properties.
Data155
Migration
A versioned change to a database's structure or data.
Product156
Minimum viable product
The smallest product experiment that can test an important assumption with real users.
Tools157
Mock
A test double configured to replace a collaborator and help verify expected calls or interactions.
AI158
Model
A learned or specified mathematical system that maps inputs to outputs.
Code159
Model-View-Controller
An architectural pattern that separates domain data and behavior, its presentation, and input handling or coordination.
Code160
Module
A unit of code with its own scope that can explicitly export values and import values from other modules.
Web161
Mount
The lifecycle event when a component is added to the rendered UI tree; unmounting removes it.
Security162
Multi-factor authentication
Authentication using more than one distinct category of factor.
Code163
Mutation
Changing an existing object or data structure in place rather than producing a separate updated value.
Product164
Navigation
The controls and structure that help users move between locations or views and understand where they are.
Web165
Nested component
A component rendered somewhere inside another component's output, forming a deeper UI hierarchy.
AI166
Neural network
A model made of connected layers of numerical operations with adjustable parameters.
Tools167
Node.js
A JavaScript runtime that executes JavaScript outside the browser and supplies APIs for tasks such as networking and file access.
Data168
NoSQL
A broad label for databases that use models other than conventional relational tables.
Tools169
npm
A JavaScript package ecosystem and command-line package manager used to install dependencies, publish packages, and run project scripts.
Tools170
npx
An npm command for executing package-provided commands, using local packages or fetching missing ones when needed.
Code171
Object
A JavaScript value that groups properties identified by string or symbol keys, often combining data and behavior.
Cloud172
Observability
The ability to understand a system's internal behavior from the signals it produces.
Web173
One-way data flow
An approach where state flows toward the UI, while events request updates through a defined path.
Basics174
Operating system
Software that manages hardware and provides services for other programs.
Web175
Optimistic updating
Updating the visible client state before a server operation is confirmed, then reconciling with the actual result.
Data176
ORM
A technique that maps application objects to relational database data.
AI177
Overfitting
Learning training-specific details so strongly that performance suffers on new data.
Tools178
Package manager
A tool that helps install and manage software packages and their dependencies.
Networks179
Packet
A unit of data transmitted over a network, with information needed to handle it.
Code180
Parallelism
Executing multiple tasks at the same time using multiple execution resources.
AI181
Parameter
A value inside a model that influences its computations and may be learned during training.
Web182
Parent component
A component that renders another component below it in the UI tree.
Security183
Phishing
Deceptive messages or sites that trick people into revealing information or taking harmful actions.
Code184
Pipeline
A sequence of stages that process input, passing results onward toward an output.
Tools185
pnpm
A JavaScript package manager that uses a shared content-addressed store and linked dependencies to reduce duplicated package data.
Networks186
Port
A numerical identifier that helps transport protocols direct traffic to the right endpoint.
Web187
POST request
An HTTP request asking a resource to process the supplied content according to that resource's rules.
Data188
Primary key
A field or set of fields that uniquely identifies each row in a table.
Basics189
Process
A running instance of a program, with its own resources and execution state.
Code190
Promise
A JavaScript object representing an eventual result: it starts pending and settles as fulfilled with a value or rejected with a reason.
AI191
Prompt
The input instructions or context given to a generative model.
AI192
Prompt engineering
Designing and testing model inputs to improve behavior for a task.
Web193
Props
Read-only inputs a React component receives, including values, objects, functions, or JSX.
Product194
Prototype
An early representation of a product used to explore or test ideas.
Networks195
Proxy
An intermediary that makes or handles requests on behalf of another party.
Tools196
Pull request
A proposal to review and integrate changes into a project's branch.
Code197
Pure function
A function whose result depends only on its inputs and that has no observable side effects.
Data198
Query
A request to retrieve or manipulate data.
AI199
RAG
A technique that retrieves relevant information and supplies it as context to a model so it can generate a better-grounded answer.
Basics200
RAM
Working memory that holds data programs need while they run.
Web201
React component
A reusable unit of React UI, usually a function that receives props and returns a description of what to render.
Web202
React.js
A JavaScript library for building user interfaces from components and updating them as data changes.
Code203
Recursion
A technique where a function solves a problem by calling itself on smaller cases.
Code204
Reducer
A function that calculates an accumulated or next value from the current value and an input; state reducers commonly use the previous state and an action.
Cloud205
Redundancy
Having extra instances or alternative resources so one component's failure does not have to stop the system.
Web206
Redux
A JavaScript state-management library where dispatched actions describe events and reducers calculate state updates in a store.
Tools207
Refactoring
Restructuring existing code to improve its design while preserving its observable behavior.
Security208
Refresh token
A credential used with an authorization server to obtain a new access token without repeating the full login flow.
AI209
Reinforcement learning
Learning a policy for actions through interaction and reward signals.
Tools210
Repository
A project's version-controlled files and recorded history.
Web211
Request header
An HTTP header field sent by a client to provide metadata or preferences for a request.
Web212
Responsive design
Designing an interface to adapt to different screen sizes, input methods, and viewing conditions.
Web213
REST
An architectural style for distributed systems built around constraints such as statelessness and a uniform interface.
Data214
Retrieve
Read or obtain stored information from a source such as a database, cache, file, or API.
Code215
Runtime
The environment and support software a program uses while executing.
Security216
Salting
Adding a unique value to each password before hashing it.
Cloud217
Scalability
A system's ability to handle more work by changing or adding resources.
Data218
Schema
A description of how data is organized, including fields, types, and constraints.
Security219
Secret
Sensitive information that grants access or must remain confidential.
Product220
Semantic HTML
Using HTML elements that describe the meaning and role of content.
Data221
Serialization
Converting data into a format suitable for storage or transmission.
Cloud222
Server
A program, or the machine running it, that provides resources or services to clients.
Web223
Server-side rendering
Generating a page's HTML on the server before sending it to the browser.
Cloud224
Serverless
A model where a provider manages server provisioning and execution infrastructure.
Web225
Session
A way to maintain continuity or state across several interactions.
Tools226
Shallow rendering
A testing approach that renders a component's immediate output without fully rendering its child components.
Tools227
Shell
A program that interprets commands and lets you interact with the operating system.
Code228
Single Responsibility Principle
A design principle that groups code around one responsibility, so it has one coherent reason to change.
Web229
Single-page application
A web application that handles much of its navigation by updating the current document through JavaScript instead of loading a new document for every view.
Tools230
Software factory
An organized set of reusable tools, templates, processes, and automation for producing and delivering software consistently.
Data231
SQL
A language used to define, query, and change data in relational databases.
Security232
SQL injection
An attack where untrusted input changes the meaning of a database command.
Code233
Stack
A structure where the most recently added item is removed first.
Web234
State management
Organizing changing application data, where it lives, how it updates, and which parts of the UI depend on it.
Code235
Statement
A unit of code that performs an action or controls execution, such as a declaration, return, or if statement.
Web236
Static site
A website served from prebuilt files instead of generating each page on demand.
Basics237
Storage
Hardware that keeps files and other data even when power is off.
Code238
String
An immutable JavaScript primitive representing text as a sequence of UTF-16 code units.
Data239
Stringify
Convert a value into a string representation; JSON.stringify specifically produces JSON text for supported values.
AI240
Supervised learning
Learning from examples that include the desired target output.
Code241
Syntactic sugar
Convenient syntax that expresses an existing operation more clearly or briefly without adding fundamentally new capability.
Networks242
TCP
A transport protocol that provides an ordered, reliable byte stream between endpoints.
Code243
Ternary operator
The JavaScript conditional operator that chooses between two expressions based on a condition, using condition ? a : b.
Tools244
Test double
A substitute for a real collaborator used during testing, including dummies, stubs, spies, mocks, and fakes.
Tools245
Test suite
A collection of tests organized to run together for a project, feature, or purpose.
Basics246
Thread
An execution path within a process that usually shares that process's memory.
Security247
TLS
A protocol for protecting communication with encryption, integrity checks, and peer authentication.
AI248
Token
A unit of input or output processed by a model, often part of a word.
AI249
Training
The process of adjusting a model using data and an objective.
Data250
Transaction
A group of database operations treated as a single unit of work.
AI251
Transformer
A neural-network architecture that uses attention to combine information from different positions.
Tools252
Transpiler
A compiler that translates source code into another source-language form, often at a similar abstraction level.
Code253
Type system
Rules a language uses to classify values and check how they are used.
Networks254
UDP
A transport protocol that sends individual messages without built-in delivery or ordering guarantees.
Web255
UI component
A reusable piece of a user interface with a defined purpose, such as a button, date picker, or navigation menu.
Code256
Uncaught SyntaxError: Unexpected token <
A parsing error that occurs when JavaScript code contains a less-than token where the parser cannot accept it.
Basics257
Unicode
A standard that assigns identifiers to characters from many writing systems.
Tools258
Unit test
A test focused on a small unit of behavior, with a narrow scope and controlled dependencies.
AI259
Unsupervised learning
Finding patterns in data without supplied target answers for each example.
Product260
Usability
How effectively, efficiently, and satisfactorily people can achieve goals with a system.
Product261
User experience
A person's overall experience of using a product or service.
Product262
User interface
The controls and presentation through which people interact with a system.
Code263
UUID
A standardized 128-bit identifier format designed to make independently generated identifiers very unlikely to collide.
Code264
var
A JavaScript declaration that creates a function-scoped or global-scoped variable rather than a block-scoped one.
Code265
Variable
A name associated with a value that a program can use.
Code266
Variable assignment
Storing a value in an existing variable binding, usually with the = operator.
Code267
Variable declaration
Introducing a variable name into a scope using a declaration such as let, const, or var.
Code268
Variable definition
Establishing what a variable is and, depending on the language, providing its storage or value.
Code269
Variable initialization
Giving a variable its initial value when its binding becomes initialized.
Data270
Vector database
A system designed to store vectors and find items with similar vector representations.
Web271
Virtual DOM
An in-memory description of a UI used to help a renderer determine which changes to apply to the actual interface.
Web272
Virtual DOM tree
The hierarchical arrangement of a UI's in-memory element descriptions, reflecting how elements are nested.
Cloud273
Virtual machine
A software-defined computer that runs its own operating system using virtualized hardware.
Security274
Vulnerability
A weakness that can be exploited to compromise a system or its users.
Web275
Web application
Software accessed through web technologies that lets users perform tasks and interact with data.
Web276
Web scraping
Programmatically extracting information from web pages, often by fetching and parsing their content.
Networks277
Webhook
An event notification sent by a service to a configured HTTP endpoint when something happens.
Web278
Website
A collection of related web pages and resources presented under a shared site identity.
Web279
WebSocket
A protocol for ongoing, two-way communication over a connection.
Basics280
Windows
Microsoft's operating-system family that manages hardware, applications, files, and the user environment.
Code281
Wrapper
Code that surrounds another function, component, or API to adapt it or add behavior.
Web282
XML
A text markup language for representing structured information with nested elements, attributes, and application-defined tags.
Web283
XMLHttpRequest
A browser API for making HTTP requests and receiving responses through events, widely used before Fetch became common.
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