Developer Glossary
Short definitions for terms you hit while debugging. Open a term for the full note.
A
- API EndpointA specific URL in an API where a resource can be accessed or an action can be triggered.
- ArtifactA by-product of the software development process, such as a compiled binary, a library, or a …
- Attack SurfaceThe total number of points (the 'attack vectors') where an unauthorized user can try to enter…
- API KeyA unique identifier used to authenticate a user, developer, or calling program to an API.
- Access TokenA credential that can be used by an application to access an API.
- ACID PropertiesA set of properties (Atomicity, Consistency, Isolation, Durability) that guarantee database t…
- AnycastA network addressing and routing method in which a single IP address is shared by multiple de…
- Alt Text (Alternative Text)A text description of an image that is displayed if the image fails to load and is read by sc…
- Anchor TextThe clickable text in a hyperlink.
B
- BashA Unix shell and command language that is the default on most Linux and macOS systems.
- Blue-Green DeploymentA deployment strategy that uses two identical production environments (Blue and Green) to min…
- Brute-Force AttackA trial-and-error method used by application programs to decode encrypted data such as passwo…
- Bearer TokenA security token that grants access to anyone who possesses it ('the bearer').
- Brute-Force ProtectionA set of security measures designed to prevent automated password-guessing attacks.
- BGP (Border Gateway Protocol)The protocol that makes the internet work by routing traffic between different autonomous sys…
- BacklinksLinks from one website to a page on another website.
C
- Client-Side Rendering (CSR)A rendering method where the browser downloads a minimal HTML page and uses JavaScript to ren…
- ClosureA feature in JavaScript where an inner function has access to the outer function's variables …
- CSS Box ModelThe fundamental layout principle of the web where every element is represented as a rectangul…
- CSS GridA two-dimensional layout system for the web that handles both rows and columns simultaneously.
- CORS PolicyA security configuration on a server that dictates which origins are allowed to access its re…
- ContainerizationThe process of packaging an application and its dependencies into an isolated unit called a c…
- CI/CD (Continuous Integration / Continuous Deployment)A set of practices that enable development teams to deliver code changes more frequently and …
- Canary ReleaseA technique to reduce the risk of introducing a new software version in production by slowly …
- Cross-Site Scripting (XSS)A security vulnerability where an attacker injects malicious scripts into a trusted website.
- Cross-Site Request Forgery (CSRF)An attack that forces an authenticated user to execute unwanted actions on a web application …
- Content Security Policy (CSP)An added layer of security that helps to detect and mitigate certain types of attacks, includ…
- CAP TheoremA principle that states a distributed data store cannot simultaneously provide more than two …
- Connection PoolingA cache of database connections maintained so that connections can be reused when future requ…
- Content Delivery Network (CDN)A system of distributed servers that deliver web content to users based on their geographic l…
- Core Web VitalsA set of specific factors that Google considers important in a webpage's overall user experie…
- Cumulative Layout Shift (CLS)A metric that measures the visual stability of a web page.
- Canonical TagAn HTML element that helps webmasters prevent duplicate content issues by specifying the 'can…
- Crawler (Bot / Spider)An automated program that browses the web to index content for search engines.
D
- Document Object Model (DOM)A programming interface for web documents that represents the page as a structured tree of ob…
- DebouncingA programming practice used to ensure that time-consuming tasks do not fire so often that the…
- DockerA platform for developing, shipping, and running applications inside lightweight, portable co…
- Docker ComposeA tool for defining and running multi-container Docker applications.
- Database IndexingA data structure technique used to quickly locate and access data in a database without havin…
- Database NormalizationThe process of organizing data in a database to reduce redundancy and improve data integrity.
- Database ReplicationThe practice of sharing information across multiple database servers to ensure data consisten…
- DNS (Domain Name System)The 'phonebook' of the internet, which translates human-readable domain names into machine-re…
E
- Event LoopThe mechanism that allows JavaScript to perform non-blocking I/O operations despite being sin…
- Edge ComputingA distributed computing paradigm that brings computation and data storage closer to the sourc…
- Environment Variables (Env Vars)Dynamic values loaded into a program at runtime to configure its behavior without changing th…
- ETL (Extract, Transform, Load)A three-step process used to move data from one system to another, typically into a data ware…
- E-E-A-TA set of guidelines used by Google's search quality raters: Experience, Expertise, Authoritat…
F
- FlexboxA one-dimensional layout model in CSS for distributing space and aligning items in a row or c…
- Foreign KeyA column or group of columns in one table that provides a link between data in two tables.
- First Contentful Paint (FCP)The time from when the page starts loading to when any part of the page's content is rendered…
G
H
- HydrationThe process where client-side JavaScript takes over a static HTML page rendered by the server…
- HoistingA behavior in JavaScript where variable and function declarations are moved to the top of the…
- HTTP MethodsA set of request methods to indicate the desired action to be performed for a given resource.
- Horizontal Scaling (Scaling Out)Adding more machines to a system to handle increased load.
- High Availability (HA)A characteristic of a system that ensures an agreed level of operational performance (usually…
- HTTPS (Hypertext Transfer Protocol Secure)The secure version of HTTP, where all communication between the browser and the website is en…
- Hashing vs. EncryptionTwo different methods of transforming data for security purposes.
- HTTP/3The third major version of the Hypertext Transfer Protocol, built on top of the QUIC protocol.
- Heading Hierarchy (H1-H6)The organizational structure of a web page's headings.
I
- Infrastructure as Code (IaC)The practice of managing and provisioning computing infrastructure through machine-readable d…
- ID TokenA security token that contains verifiable claims about an authenticated user.
- IP Address (IPv4 vs. IPv6)A numerical label assigned to each device connected to a computer network.
- Interaction to Next Paint (INP)A metric that assesses a page's overall responsiveness to user interactions.
- Internal LinkingThe practice of linking to other pages on the same website.
- IndexingThe process by which search engines organize and store information from the web to display it…
J
K
L
- Load BalancerA device or software that distributes network or application traffic across a cluster of serv…
- Latency vs. BandwidthTwo metrics that define network performance.
- Lighthouse AuditAn open-source, automated tool by Google for improving the quality of web pages.
- Long-tail KeywordsSpecific, three-to-four word phrases that are very relevant to what you are selling.
M
- MemoizationAn optimization technique that speeds up programs by storing the results of expensive functio…
- Mobile-First DesignA design strategy where the mobile version of a website is developed first, and features are …
- MicroservicesAn architectural style that structures an application as a collection of small, independent s…
- Monolithic ArchitectureAn architectural pattern where all components of an application are bundled into a single unit.
- Multi-Factor Authentication (MFA)A security system that requires more than one method of authentication from independent categ…
- Man-in-the-Middle (MITM) AttackAn attack where the attacker secretly relays and possibly alters the communication between tw…
- Meta DescriptionAn HTML attribute that provides a brief summary of a web page.
N
O
- ObservabilityThe ability to measure the internal state of a system by examining its external outputs (logs…
- OrchestrationThe automated configuration, management, and coordination of complex computer systems and ser…
- OAuth 2.0An open standard for access delegation, commonly used as a way for users to grant application…
- OpenID Connect (OIDC)An identity layer built on top of the OAuth 2.0 protocol.
- OLAP vs. OLTPTwo different types of database processing architectures.
- Object-Relational Mapping (ORM)A technique that lets you query and manipulate data from a database using an object-oriented …
- OSI ModelA conceptual framework used to understand how different networking protocols interact.
- Open Graph (OG)A protocol that allows any web page to become a rich object in a social graph.
P
- Progressive Web App (PWA)A type of application software delivered through the web, built using common web technologies…
- Principle of Least Privilege (PoLP)The concept that a user, program, or process should have only the bare minimum privileges nec…
- Penetration Testing (Pentesting)An authorized simulated cyberattack on a computer system, performed to evaluate the security …
- Primary KeyA unique identifier for a specific record in a database table.
Q
R
- Responsive Web Design (RWD)An approach to web design that makes web pages render well on a variety of devices and window…
- REST APIAn application programming interface that conforms to the constraints of REST architectural s…
- Reverse ProxyA server that sits in front of backend servers and forwards client requests to those servers.
- RegistryA central repository for storing and managing software artifacts, most commonly Docker images.
- RollbackThe process of returning a system to a previously stable state after a failed deployment.
- Rate LimitingA strategy for limiting network traffic to prevent users from exhausting system resources or …
- Role-Based Access Control (RBAC)A method of restricting network access based on the roles of individual users within an enter…
- Refresh TokenA special type of token used to obtain a new access token when the current one expires.
- REST (Representational State Transfer)An architectural style for providing interoperability between computer systems on the internet.
- Robots.txtA text file used by websites to communicate with web crawlers and other web robots.
S
- Shadow DOMA web standard that provides encapsulation for JavaScript, CSS, and templating in a web compo…
- Server-Side Rendering (SSR)The process of rendering a web page on the server and sending the fully constructed HTML to t…
- Semantic HTMLThe use of HTML tags that convey the meaning and structure of the content rather than just it…
- Single Page Application (SPA)A web application that interacts with the user by dynamically rewriting the current page rath…
- Service WorkerA script that your browser runs in the background, separate from a web page, enabling feature…
- Serverless ComputingA cloud computing model where the provider manages the server infrastructure and automaticall…
- SSH (Secure Shell)A cryptographic network protocol for operating network services securely over an unsecured ne…
- Shell ScriptingThe practice of writing scripts for the command line to automate repetitive tasks.
- Secrets ManagementThe practice of securely storing and managing sensitive information like API keys, passwords,…
- SQL Injection (SQLi)A type of vulnerability where an attacker can interfere with the queries that an application …
- Salt & Pepper (Cryptography)Random data added to a password before it is hashed to protect against rainbow table and brut…
- Same-Origin Policy (SOP)A critical security mechanism that restricts how a document or script loaded by one origin ca…
- Single Sign-On (SSO)An authentication scheme that allows a user to log in with a single ID to any of several rela…
- Session HijackingAn attack where a hacker steals a user's session ID and uses it to impersonate them.
- SAML (Security Assertion Markup Language)An XML-based open standard for exchanging authentication and authorization data between parties.
- SQL (Structured Query Language)The standard language for managing and manipulating relational databases.
- ShardingA database architecture pattern that involves breaking a very large database into smaller, fa…
- Search Engine Optimization (SEO)The practice of orienting your website to rank higher on a search engine results page (SERP).
- Schema Markup (JSON-LD)Structured data added to a website to help search engines understand its content and provide …
- SitemapAn XML file that lists all the important pages of a website, ensuring search engines can find…
- Search IntentThe underlying goal a user has when typing a query into a search engine.
- SERP (Search Engine Results Page)The page displayed by a search engine in response to a query by a searcher.
- Semantic SearchA search engine's attempt to understand the searcher's intent and the contextual meaning of t…
T
- ThrottlingA technique that limits the execution of a function to at most once in a specified period of …
- TypeScriptA strongly typed superset of JavaScript that compiles to plain JavaScript.
- Type SafetyA feature of a programming language that prevents type errors by ensuring that operations are…
- TerraformAn open-source infrastructure as code tool that allows you to build, change, and version clou…
- TLS / SSLCryptographic protocols designed to provide communications security over a computer network.
- TCP/IP StackThe set of communications protocols used for the internet and similar computer networks.
- TTL (Time to Live)A value in an IP packet or a DNS record that tells the network how long to keep the data befo…
- Time to First Byte (TTFB)The time it takes for a browser to receive the first byte of data from the server.
- Topical AuthorityA measure of a website's depth of knowledge and credibility on a specific subject.
- Twitter CardsMeta tags similar to Open Graph but specifically for enhancing links shared on X (formerly Tw…
- Technical SEOWebsite and server optimizations that help search engine spiders crawl and index your site mo…
U
V
- Virtual DOMA lightweight, in-memory representation of the real DOM used by frameworks like React to opti…
- Vertical Scaling (Scaling Up)Increasing the capacity of a single machine by adding more CPU, RAM, or storage.
- Virtual Machine (VM)An emulation of a computer system that runs on top of a physical host using a hypervisor.
- Vulnerability ScanningAn automated process of identifying security weaknesses in computer systems, networks, or app…
- Vector DatabaseA type of database that stores and indexes data as high-dimensional vectors (embeddings).
W
- Web Accessibility (A11y)The practice of making websites usable by as many people as possible, including those with di…
- Web Content Accessibility Guidelines (WCAG)The international standard for web accessibility developed by the W3C.
- WebSocketA communications protocol that provides a persistent, full-duplex connection between a client…