Glossary

What Is Python

Definition Python is a general-purpose programming language designed to be readable and straightforward. Its syntax is clean and close to plain English compared with many other languages, which makes it accessible to beginners while remaining powerful enough for experienced engineers. Python is used across a wide range of applications — web development, data analysis, artificial intelligence, automation, scientific computing, and...

What Is RAG

Definition Retrieval-augmented generation (RAG) is a technique that improves the accuracy and relevance of AI-generated responses by first retrieving relevant information from a knowledge base and then using that information as context when generating an answer. Instead of relying solely on what the language model learned during training — which may be outdated or too general — RAG fetches specific,...

What Is React

Definition React is an open-source JavaScript library, originally created by Facebook (now Meta), for building user interfaces. It allows developers to create web applications where the page updates dynamically without needing a full reload every time the user clicks something. React works by breaking the interface into small, reusable pieces called components — a navigation bar, a search box, a...

What Is React Native

Definition React Native is an open-source framework created by Meta (formerly Facebook) for building mobile applications that run natively on both iOS and Android from a single codebase. It uses the same component-based approach as React (the web library), but instead of rendering to a web browser, it renders to native mobile interface elements — real iOS buttons, real Android...

What Is Redis

Definition Redis is an open-source, in-memory data store that keeps frequently accessed data in your server’s RAM rather than on disk. Because RAM is orders of magnitude faster than disk storage, Redis can read and write data in microseconds. It is most commonly used for caching (storing pre-computed results), managing user sessions, powering real-time features like live notifications, and handling...

What Is Refactoring

Definition Refactoring is the process of restructuring existing code to make it cleaner, more efficient, or easier to maintain, without changing what it actually does from the user’s perspective. The software behaves exactly the same before and after — the improvements are internal. It is comparable to reorganising a warehouse: the same products are stored and shipped, but the layout...

What Is a Repository

Definition A repository (often shortened to “repo”) is the central location where all the files, version history, and changes for a software project are stored. Think of it as a project folder with a built-in memory — it records every change ever made, who made it, and when. Repositories are typically hosted on platforms like GitHub or Bitbucket, which add...

What Is Responsive Design

Definition Responsive design is an approach to building websites and applications so they automatically adjust their layout to fit any screen size — from a large desktop monitor to a tablet to a mobile phone. Rather than building separate versions for different devices, a responsively designed site uses flexible grids, scalable images, and layout rules that adapt based on the...

What Is a REST API

Definition A REST API (Representational State Transfer API) is a specific style of API that uses standard web protocols to send and receive data. It works over the same technology as regular web browsing — URLs and HTTP requests — which makes it the most widely used approach for connecting web applications, mobile apps, and business systems. When a developer...

What Is a Retainer

Definition A retainer is a recurring arrangement where a client pays a fixed amount on a regular basis — usually monthly — in exchange for ongoing access to services. Rather than commissioning work project by project, the client secures a set allocation of time, support, or expertise. In the context of digital agencies and software companies, retainers typically cover ongoing...

What Is a Reverse Proxy

Definition A reverse proxy is a server that sits between your website visitors and your actual web server. When someone visits your site, their request goes to the reverse proxy first, which then forwards it to the appropriate backend server, receives the response, and sends it back to the visitor. The visitor never communicates directly with your backend. This intermediary...

What Is Robotic Process Automation

Definition Robotic Process Automation (RPA) is the use of software bots to carry out repetitive, rule-based tasks that a person would normally do on a computer. These bots can click buttons, copy data between systems, fill in forms, send emails, and follow predefined workflows — all without human intervention. Despite the name, there are no physical robots involved. The “robot”...

What Is robots.txt

Definition robots.txt is a small text file that sits at the root of your website and gives instructions to search engine bots about which pages or sections of your site they are allowed to crawl. It acts as a set of ground rules — you can use it to block bots from accessing areas that are not useful in search...

What Is ROI

Definition ROI stands for Return on Investment — it is a measure of how much value you gain relative to how much you spend. In its simplest form, ROI compares the benefit of an investment to its cost. If you spend ten thousand pounds on a system that saves you twenty thousand pounds per year in manual work, the ROI...

What Is Role-Based Access Control

Definition Role-Based Access Control (RBAC) is a method of managing what users can see and do within a system by assigning them to roles, where each role has a defined set of permissions. Instead of configuring access for every individual user, you create roles — such as Admin, Manager, Editor, or Viewer — and assign the appropriate permissions to each...

What Is a Route

Definition A route is a rule that maps a web address to a specific action inside an application. When someone visits a URL or a system sends a request, the application checks its list of routes to determine what should happen. Routes connect the address someone is requesting — like “/projects” or “/invoices/123” — to the piece of code that...

What Is SaaS

Definition SaaS stands for Software as a Service — it is software that you access over the internet and pay for on a recurring basis, typically monthly or annually. Instead of buying a licence and installing software on your own computers or servers, you log in through a browser and the provider handles everything: hosting, updates, security, and maintenance. Common...

What Is Scalability

Definition Scalability is the ability of a system — whether a website, application, or entire IT infrastructure — to handle increasing amounts of work without performance suffering or costs spiralling out of control. A scalable system can accommodate more users, more data, or more transactions by adding resources in a predictable way. Scalability comes in two forms: vertical scaling (making...

What Is a Schema

Definition A schema is a blueprint that defines how data is organised within a system. It specifies what types of information are stored, how they relate to each other, and what rules apply — such as which fields are required, what format dates should be in, or whether a customer record must have an email address. Think of it as...

What Is Schema Markup

Definition Schema markup is structured data added to your website’s code that helps search engines understand what your content means, not just what it says. It uses a standardised vocabulary (from schema.org) to label things explicitly — telling Google that a particular piece of text is a business name, a product price, an event date, a review rating, or a...

What Is Scope Creep

Definition Scope creep is the gradual expansion of a project beyond its original brief, usually without a formal decision to increase the budget, timeline, or resources. It happens when new requests, ideas, or “quick additions” pile up during a project — each one small on its own, but collectively enough to derail the plan. The original agreement said ten pages;...

What Is Scrum

Definition Scrum is a framework for agile development that organises work into sprints with defined roles, ceremonies, and review cadences. Why It Matters Scrum provides structure to agile. Without a framework, agile drifts into chaos. Scrum keeps teams focused and gives stakeholders regular visibility into progress. Example A daily standup reveals a developer blocked on API credentials. The scrum master...

What Is an SDK

Definition An SDK (Software Development Kit) is a collection of pre-built tools, code libraries, and documentation that helps developers build for a specific platform or integrate with a specific service. Rather than figuring out every technical detail from scratch, a developer uses the SDK as a shortcut — it handles the low-level work so they can focus on the functionality...

What Is SEO

Definition SEO stands for search engine optimisation — the practice of improving your website so it appears higher in search engine results for terms your potential customers are searching for. It covers everything from the words on your pages and the structure of your site to how fast it loads and how many other websites link to it. The goal...

What Is a SERP

Definition SERP stands for search engine results page — the page a search engine displays after you type in a query and hit enter. It is what most people simply call “the Google results.” A modern SERP is far more than ten blue links. It can include paid ads at the top, a local map pack, featured snippets (answer boxes),...

What Is a Server

Definition A server is a computer that stores, processes, and delivers data to other computers over a network. When someone visits your website, their browser sends a request to your server, which processes that request and sends back the web page. Servers run specialised software designed to handle many simultaneous requests efficiently. They can be physical machines housed in data...

What Is Server-Side Rendering

Definition Server-side rendering (SSR) is a method where web pages are built on the server and sent to the browser as complete, ready-to-display HTML. When a user requests a page, the server fetches the necessary data, assembles the full page, and delivers it. The browser receives a finished page and can display it immediately. This is the traditional way websites...

What Is Shopify

Definition Shopify is a hosted e-commerce platform that provides everything a business needs to sell products online. It handles the website, the product catalogue, the shopping cart, payment processing, shipping calculations, tax management, and order fulfilment — all through a single subscription service. Because Shopify is hosted (meaning it runs on Shopify’s own servers), you do not need to manage...

What Is a Single Page Application

Definition A single page application (SPA) is a web application that loads once in the browser and then updates its content dynamically without reloading the entire page. In a traditional website, clicking a link loads a completely new page from the server. In an SPA, the application stays loaded and only fetches the specific data it needs, swapping content in...

What Is an SOP

Definition SOP stands for Standard Operating Procedure — it is a documented, step-by-step set of instructions for completing a specific recurring task or process within a business. SOPs define how something should be done, by whom, and in what order, so the outcome is consistent regardless of who performs it. They can cover anything from onboarding a new client to...

What Is a Sprint

Definition A sprint is a fixed-length development cycle, typically two weeks, during which a team commits to completing a defined set of work. Why It Matters Sprints create a predictable rhythm for delivery. You see working software every two weeks, problems are caught early, and priorities adjust based on real feedback. Example A team plans a two-week sprint to build...

What Is SQL

Definition SQL (Structured Query Language) is the standard language used to communicate with relational databases. It allows you to ask questions of your data (“show me all customers who signed up this month”), make changes (“update this product’s price”), and define structure (“create a new table for invoices”). SQL has been the dominant database language since the 1970s and is...

What Is SQL Injection

Definition SQL injection is a type of cyberattack where an attacker inserts malicious database commands into an input field — such as a login form, search bar, or URL parameter — that the website passes directly to its database without proper validation. If the application does not sanitise the input, the database executes the attacker’s commands as though they were...

What Are SSL and TLS

Definition SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are security protocols that encrypt the connection between a website and its visitors. When you see a padlock icon in your browser’s address bar or a URL starting with “https,” that means SSL/TLS is active. The encryption ensures that any data travelling between the visitor’s browser and the web server...

What Is an SSL Certificate

Definition An SSL certificate (technically TLS certificate, but SSL remains the common name) is a small data file installed on a web server that does two things: it verifies that the website genuinely belongs to the organisation claiming to own it, and it enables an encrypted connection between the server and the visitor’s browser. When a site has a valid...

What Is a Staging Environment

Definition A staging environment is a copy of your live system that is used for testing changes before they reach real users. It mirrors the production environment as closely as possible — same server configuration, same software versions, same database structure — so that anything tested on staging behaves the same way when deployed to production. It is the final...

What Is Stripe

Definition Stripe is an online payment processing platform that allows businesses to accept payments over the internet. It provides the infrastructure for handling credit and debit card transactions, direct debits, digital wallet payments, and recurring subscriptions. Developers integrate Stripe into websites and applications using its API, and Stripe handles the complex, regulated parts — securely processing card details, managing PCI...

What Is Structured Data

Definition Structured data is additional code added to your web pages that tells search engines exactly what your content means, not just what it says. It uses a standardised vocabulary called Schema.org to label things like products, reviews, events, FAQs, and business details in a way machines can reliably interpret. For example, rather than hoping Google figures out that “4.8”...

What Is Tailwind CSS

Definition Tailwind CSS is a utility-first CSS framework used by developers to style websites and web applications. Unlike traditional CSS frameworks that provide pre-designed components (like a ready-made navigation bar or card layout), Tailwind provides small, single-purpose classes that each do one thing — set a font size, add padding, change a colour, control spacing. Developers combine these utility classes...

What Is Technical Debt

Definition Technical debt is the accumulated cost of shortcuts, workarounds, and deferred improvements in a software codebase. Like financial debt, it accrues interest — each shortcut makes the next change slightly harder and more expensive, and the cumulative effect eventually slows development to a crawl. Why It Matters Every software project accumulates some technical debt — it is a natural...

What Is Technical SEO

Definition Technical SEO is the behind-the-scenes work that ensures search engines can properly crawl, understand, and index your website. It has nothing to do with the words on your pages or the links pointing to your site — those fall under on-page and off-page SEO. Instead, technical SEO focuses on site speed, mobile-friendliness, secure connections (HTTPS), clean URL structures, XML...

What Is a Token (in AI)

Definition In the context of AI language models, a token is a chunk of text that the model treats as a single unit when processing input or generating output. A token might be a whole word, part of a word, a punctuation mark, or even a space. For example, the word “understanding” might be split into two tokens: “understand” and...

What Is Training Data

Definition Training data is the collection of examples that a machine learning model learns from during its development. Each example typically consists of an input and the correct corresponding output — a photo labelled “cat” or “dog”, an email marked “spam” or “not spam”, a customer query paired with the appropriate response. The model studies these examples to identify patterns...

What Is Two-Factor Authentication

Definition Two-factor authentication (2FA) is a security method that requires two separate forms of verification before granting access to an account. The first factor is typically something you know — your password. The second factor is something you have — usually a code sent to your phone, generated by an authenticator app, or provided by a physical security key. The...

What Is TypeScript

Definition TypeScript is a programming language built on top of JavaScript that adds static type checking. In plain terms, it lets developers define what kind of data each variable, function, and component should work with — a number, a string, a list of products — and then catches mistakes at development time rather than after the application is live. TypeScript...

What Is Unit Testing

Definition Unit testing is the practice of writing small, automated tests that check individual pieces of code — called units — in isolation. A unit is typically a single function or method that performs one specific task, such as calculating a discount or validating an email address. The test provides known inputs and checks that the output matches what is...

What Is Uptime

Definition Uptime is the percentage of time a website, server, or service is operational and accessible. It is typically expressed as a percentage over a given period — 99.9% uptime over a year, for example, means the service was unavailable for roughly eight hours and forty-five minutes across the entire year. Hosting providers and service-level agreements (SLAs) use uptime guarantees...

What Is a User Story

Definition A user story is a short description of a feature written from the user perspective: as a [role], I want [something], so that [benefit]. Why It Matters User stories keep development grounded in real needs rather than technical specifications. A feature that does not match how users work is wasted effort. Example Instead of build a date filter component,...

What Is a Vector Database

Definition A vector database is a specialised database designed to store, index, and search vectors — the numerical representations (embeddings) that AI models produce from text, images, or other data. While a traditional database excels at finding exact matches (show me all orders from customer 4521), a vector database excels at finding similar items (show me all documents that are...

What Is Version Control

Definition Version control is a system that records every change made to a codebase, who made it, and when. It maintains a complete history of the project, allowing developers to review past changes, revert to earlier versions, and work on different features simultaneously without overwriting each other’s work. It is the equivalent of track changes in a document editor, but...

What Is a VPS

Definition A VPS (Virtual Private Server) is a hosting environment that gives you a dedicated portion of a physical server’s resources. The physical machine is divided into multiple virtual servers using software called a hypervisor, and each VPS operates independently with its own allocated CPU, memory, and storage. Unlike shared hosting, where resources are pooled and your site competes with...

What Is a Vulnerability

Definition A vulnerability is a weakness or flaw in a piece of software, a system, or a process that an attacker could exploit to gain unauthorised access, steal data, or cause damage. Vulnerabilities can exist in application code, server configurations, third-party plugins, operating systems, or even in the way people follow (or ignore) security procedures. They are not attacks themselves...

What Is a Webhook

Definition A webhook is an automatic message sent from one system to another when a specific event happens. Unlike a regular API call where your system asks for information, a webhook is the reverse — the other system tells yours that something has occurred. It is a push notification between servers, triggered instantly by events like a payment completing, a...

What Is WooCommerce

Definition WooCommerce is a free, open-source e-commerce plugin for WordPress. It adds online shop functionality to a WordPress website, allowing you to list products, manage inventory, accept payments, calculate shipping, handle tax, and process orders — all from the same WordPress admin dashboard you already use to manage your content. WooCommerce supports physical products, digital downloads, subscriptions, and bookings. Its...

What Is WordPress

Definition WordPress is a free, open-source content management system (CMS) that allows you to build and manage websites without writing code from scratch. It started as a blogging platform in 2003 and has since grown into a full website-building framework used by businesses, publishers, and organisations of all sizes. WordPress provides an admin dashboard where you can create pages, publish...

What Is a Workflow

Definition A workflow is a defined sequence of steps, decisions, and handoffs that moves a task or process from start to completion. Workflows can be manual (a checklist that a team follows), semi-automated (some steps handled by software, others by people), or fully automated (the entire sequence runs without human involvement). In software and business operations, workflows formalise how work...

What Is Workflow Automation

Definition Workflow automation is the use of software to perform a sequence of business tasks automatically, following predefined rules and triggers, with little or no human intervention for routine cases. It replaces manual, repetitive processes — passing documents between departments, sending follow-up emails, updating records across systems, generating reports — with automated sequences that execute consistently every time. Workflows can...

What Is an XML Sitemap

Definition An XML sitemap is a file that lists every important page on your website in a format search engines can read. It acts like a table of contents, telling Google, Bing, and other search engines which pages exist, when they were last updated, and how important they are relative to each other. The file uses a standardised format called...

What Is XSS

Definition XSS (Cross-Site Scripting) is a type of security vulnerability where an attacker manages to inject malicious code — usually JavaScript — into a website that other people visit. When a visitor loads the affected page, the injected code runs in their browser as if it were a legitimate part of the site. This can allow the attacker to steal...

What Is Zero Trust

Definition Zero trust is a security model built on a simple principle: never trust, always verify. Traditional security assumes that anything inside the company network is safe and anything outside is a threat. Zero trust rejects that assumption entirely. Every user, device, and application must prove its identity and authorisation before accessing any resource, regardless of whether the request comes...