Product

The No-BS Tech Lingo Guide for Non-Technical Founders

Has your developer ever spoken at you in a tone that made you nod along while you had no idea what they meant? You're not slow. The lingo is the problem.

I've sat in too many calls where a non-technical founder gets buried in acronyms (SSR, CDN, ORM, OAuth) and ends up agreeing to things they don't fully understand. Sometimes the person quoting them doesn't even understand it themself. That's how people get scammed.

So here it is. Every word in tech and software you might hear, explained simply, with a real-world example where it helps. Search the box below for any word you've heard. If it's geeky, you'll get a London metaphor. If it's not, you'll get a straight one-liner.

The point is to keep things simple. If you want to learn the lingo, this is your starting line. If you don't, that's fine too. You can hand this to your developer and say "speak to me like the bit on the right."

320 terms

Languages

HTML

HyperText Markup Language

Short for HyperText Markup Language. The skeleton of every web page. It's what tells the browser what's a heading, what's a paragraph, what's an image.

In real life

The bricks of a house. Without them, nothing stands up.

CSS

Cascading Style Sheets

Short for Cascading Style Sheets. The styling — colours, fonts, spacing, layout. CSS is what makes a site look like something instead of looking like a Word document from 1998.

In real life

The paint, the wallpaper, the furniture. The bricks were HTML; CSS is everything you actually see.

JavaScript

The language that makes web pages do things. Click a button and a menu opens? That's JavaScript.

In real life

The electrics in the house. The walls are up, the paint is on, but flick a switch and that's JavaScript turning the lights on.

TypeScript

JavaScript with safety rails. It catches mistakes before the code runs, so fewer bugs make it to your customers.

In real life

Same car, but with seatbelts and airbags fitted.

Python

A general-purpose language used everywhere — websites, AI, data analysis, automation. Easy to read, which is why it's the most popular language in the world right now.

In real life

A Swiss Army knife. Not the prettiest, but it does almost everything.

Ruby

A language famous for being pleasant to write. Most people meet it through Ruby on Rails (used by Shopify, GitHub, Airbnb early on).

PHP

Hypertext Preprocessor

Short for Hypertext Preprocessor. An older language that still runs a huge chunk of the internet — WordPress, Facebook's early days, most of your local plumber's website.

Java

A heavyweight language used by big banks, big enterprise software, and Android apps. Not the same as JavaScript — totally different thing.

Kotlin

The modern way to build Android apps. Replaced Java as Google's preferred language for Android.

Swift

Apple's language for building iPhone, iPad, and Mac apps. If your dev says they're "writing it in Swift," they mean a native iOS app.

Objective-C

The old language for iPhone apps before Swift came along in 2014. Still hanging around in legacy codebases.

Go

Golang

A language built by Google for fast, server-side software. Loved for being simple and quick.

Rust

A modern language obsessed with safety and speed. Used where performance matters — browsers, operating systems, infrastructure tools.

C

The granddaddy language. Operating systems, embedded chips, the foundations of almost every other language are built in C.

C++

C with more features. Used for games, browsers, and anywhere you need raw speed.

C#

CSharp

Microsoft's main language. Big in enterprise software, Windows apps, and Unity (game development).

Dart

Google's language. You'll only run into it if you're using Flutter to build apps.

R

A language built specifically for statistics and data science. Used by analysts, researchers, and academics.

MATLAB

A language and tool for engineers and scientists doing heavy maths and simulations. You'll rarely see it in normal product work.

SQL

Structured Query Language

Short for Structured Query Language (often pronounced "sequel"). The language used to talk to databases. "Get me all customers in London who spent over £100" is one SQL query.

In real life

Asking the librarian a question. SQL is how you phrase it so they bring back the right book.

Bash

Bourne Again SHell

Short for Bourne Again SHell. The default scripting language inside Mac and Linux terminals. Used to automate file management, deployments, and admin tasks.

Zsh

A fancier version of Bash. Default shell on modern Macs.

PowerShell

Microsoft's version of Bash. The way Windows admins automate things.

Lua

A small, fast scripting language. Mostly seen in games (Roblox runs on it) and embedded inside other software.

Perl

An older scripting language. Powerful for text processing, but rare in new projects.

Scala

A language often used at companies handling huge amounts of data — Twitter, LinkedIn, banks.

Elixir

A language built for systems that handle millions of users at once — chat apps, real-time dashboards, messaging platforms.

Haskell

An academic, mathematical language. You'll mostly see it in research, finance, or projects with very strict correctness requirements.

Clojure

A modern take on a very old language (Lisp). Niche but devoted following.

Solidity

The language used to write smart contracts on Ethereum and similar blockchains.

WebAssembly

Wasm

A way to run fast, compiled code (from C, Rust, etc.) inside a web browser at near-native speed.

In real life

Letting a Formula 1 engine run inside the family car.

JSON

JavaScript Object Notation

Short for JavaScript Object Notation (pronounced "jay-son"). A simple text format for sending data between systems. The most common way two pieces of software talk to each other on the modern web.

XML

eXtensible Markup Language

Short for eXtensible Markup Language. An older data format, like JSON's clunkier older brother. Still used in legacy systems and some enterprise software.

YAML

YAML Ain't Markup Language

Short for YAML Ain't Markup Language (yes, that's the actual name). A clean, readable format used mostly for config files — telling tools what to do without writing code.

Markdown

A simple way to write formatted text using plain symbols. # for a heading, ** for bold. This site's blog is written in something close to it.

Frontend Frameworks

React

ReactJS

A tool for building website interfaces in reusable chunks. The most popular front-end framework in the world.

In real life

Lego blocks. You build a button once, then snap it in wherever you need it.

Next.js

Next · NextJS

A framework built on top of React that handles the boring stuff — routing, performance, SEO. This site is built in Next.js.

In real life

React is the engine. Next.js is the whole car around it.

Vue

VueJS · Vue.js

An alternative to React. Smaller, often easier to pick up. Popular in Europe and Asia.

Nuxt

What Next.js is to React, Nuxt is to Vue. Same idea — a framework that does the heavy lifting.

Angular

Google's heavyweight front-end framework. Common in big enterprise apps. More structured (and stricter) than React.

Svelte

A newer competitor to React. Loved for being lighter and faster, with simpler code.

SvelteKit

What Next.js is to React. The full-app framework built on top of Svelte.

Solid

SolidJS

A React-style framework focused on raw performance. Niche but growing.

Astro

A framework optimised for content-heavy sites — blogs, marketing pages, documentation. Ships almost no JavaScript by default, so it's fast.

Remix

Another React framework, similar territory to Next.js. Strong on forms and traditional web fundamentals.

jQuery

The library that ruled the web in the 2000s. Still everywhere on older sites, but barely used in new builds.

Tailwind CSS

Tailwind

A way of styling websites by adding short class names directly to elements. Faster than writing traditional CSS for most teams.

Bootstrap

A pre-built design system. Drop it in and your site has buttons, forms, and grids ready to go. Why so many sites in 2014 looked the same.

Material UI

MUI

A React component library based on Google's Material Design. Gives you ready-made buttons, modals, dropdowns out of the box.

shadcn/ui

shadcn

A modern set of copy-paste UI components for React. Not a library you install — you copy the code in and own it. Used on this site.

Storybook

A workshop for building and testing UI components in isolation, before they get plugged into the live site.

Backend & APIs

Node.js

Node

JavaScript that runs on the server instead of in the browser. Lets one team write the same language across the whole stack.

Express

The original tool for building servers in Node.js. Old, simple, still everywhere.

Fastify

A modern, faster alternative to Express. Same job, better performance.

NestJS

Nest

A more structured Node.js framework, popular with teams coming from Java or Angular backgrounds.

Django

Python's biggest web framework. Comes with batteries included — admin panels, user logins, database tools, all built in.

Flask

A lightweight Python framework. You build the bits you need; nothing comes pre-packaged.

FastAPI

A modern Python framework focused on building APIs quickly. Popular for AI-related backends.

Ruby on Rails

Rails

The framework that made Ruby famous. Get a working web app up in an afternoon. Built Shopify, GitHub, Basecamp.

Laravel

The biggest PHP framework. The modern way to build PHP apps without it feeling stuck in 2005.

Spring

Spring Boot

The dominant framework for Java backends. Most big bank and enterprise systems run on it.

.NET

dotnet · ASP.NET

Microsoft's platform for building backends, mostly in C#. Common in big corporate environments.

Phoenix

Elixir's main web framework. Great for real-time stuff like chat and live dashboards.

API

Application Programming Interface

Short for Application Programming Interface. A way for two pieces of software to talk to each other. When your site "connects to Stripe," it's using Stripe's API.

In real life

The waiter at a restaurant. You don't go into the kitchen — you tell the waiter what you want, they bring it back.

REST API

REST · RESTful · Representational State Transfer

REST is short for Representational State Transfer. The most common style of API. Predictable URLs, standard verbs (GET, POST, etc.). Probably what your dev means when they just say "the API."

GraphQL

Graph Query Language

Short for Graph Query Language. A different style of API where the front-end asks for exactly the fields it needs, instead of getting everything back.

In real life

Ordering off a menu vs. a buffet. REST gives you the buffet; GraphQL lets you order the exact dish you want.

gRPC

Google Remote Procedure Call

Short for Google Remote Procedure Call. A faster, stricter way for servers to talk to each other. Common inside big systems where speed matters more than browser-friendliness.

WebSockets

A way to keep a live connection open between the browser and the server. Used for chat, live notifications, multiplayer.

In real life

A normal API is a phone call where you hang up after each question. WebSockets is leaving the line open.

Webhook

A way for an external service to notify your app when something happens. Stripe pings your server when a payment succeeds — that's a webhook.

In real life

A doorbell. Stripe rings; your app answers.

OAuth

Open Authorization

Short for Open Authorization. The standard way to "Sign in with Google" or "Sign in with Apple." Lets users log in without giving you their password.

In real life

A bouncer at a club. You don't show your bank card — Google vouches for you and the bouncer waves you in.

JWT

JSON Web Token

Short for JSON Web Token (often pronounced "jot"). A small, signed token a server gives you to prove you're logged in. Sent with every request so the server doesn't have to ask "who are you?" each time.

In real life

A festival wristband. You got it at the gate; now flash it everywhere inside.

API key

A long secret string that proves your app is allowed to use someone else's service. Treat it like a password — never put it in public code.

Rate limiting

Capping how many times someone can hit your API in a window of time. Stops bots, abuse, and runaway costs.

In real life

The bouncer letting people in one at a time so the club doesn't get crushed.

CORS

Cross-Origin Resource Sharing

A browser rule about which websites are allowed to talk to which APIs. When your dev says "I've got a CORS issue," the browser is blocking a request.

Endpoint

A specific URL on an API that does one thing. /users gets the user list; /orders gets orders.

Middleware

Code that runs between a request coming in and the response going out. Used for things like checking logins, logging, or rate limiting.

Databases

Database

Where your app stores its data — users, orders, posts, anything that needs to stick around.

In real life

A really, really good filing cabinet.

PostgreSQL

Postgres · Post-gres-Q-L

Short for Postgres Structured Query Language. The most popular serious open-source database. Reliable, powerful, the default choice for most modern apps.

MySQL

My Structured Query Language

Short for My Structured Query Language (named after the founder's daughter, My). Another major open-source database. Older than Postgres, still hugely popular, especially with WordPress and PHP apps.

MariaDB

A fork of MySQL run by the open-source community after Oracle bought MySQL. Very similar in practice.

SQLite

SQL Lite

A lightweight version of SQL — short for Structured Query Language Lite. A tiny database that lives in a single file. Used in mobile apps, browsers, and small projects where you don't want to run a server.

In real life

Postgres is a warehouse. SQLite is a notebook in your back pocket.

MongoDB

Mongo · Humongous Database

Short for "Humongous DB" (database). A NoSQL database — stores data as flexible documents instead of rigid rows and columns. Popular with Node.js apps.

Redis

REmote DIctionary Server

Short for Remote Dictionary Server. A super-fast in-memory database. Used as a cache, for queues, and for real-time features.

In real life

Postgres is the warehouse. Redis is the shelf right behind the till.

DynamoDB

Amazon's NoSQL database. Scales to enormous size; popular inside AWS-heavy stacks.

Firestore

Firebase Firestore

Google's real-time database, part of Firebase. Loved by mobile and prototype builders for syncing data live.

Supabase

An open-source alternative to Firebase. Postgres under the hood, with auth and APIs included.

Prisma

A tool that makes talking to a database easier in code. Most modern Node.js apps use it.

Drizzle

A newer, lighter alternative to Prisma. Same idea — write database queries in your code without raw SQL.

ORM

Object-Relational Mapper

Short for Object-Relational Mapper. A layer that lets you talk to a database using normal code instead of raw SQL.

In real life

A translator between you and the librarian. You speak English; the ORM speaks SQL on your behalf.

Schema

The blueprint of a database — what tables exist, what columns they have, what type of data goes in each.

In real life

The form you fill in at the council. The schema decides which boxes exist and what goes in them.

Migration

A controlled change to the database structure — adding a column, renaming a table. Versioned so the team stays in sync.

Index

Indexing

An extra structure that makes database lookups fast. Without one, finding a record means scanning every row.

In real life

The index at the back of a book. Don't read every page — jump to the right one.

Sharding

Splitting a database across multiple servers when one is too small. Used at very large scale.

Replication

Keeping a live copy of your database somewhere else, in case the main one fails or for faster reads.

Query

A request to a database. "Get all customers from London" is a query.

Backup

A saved copy of your database. If something goes wrong, you restore from a backup. If you don't have one, you have a problem.

Mobile

iOS

Apple's mobile operating system. Runs on iPhone and iPad.

Android

Google's mobile operating system. Runs on most non-Apple phones.

Native app

An app built specifically for one platform using its native tools — Swift for iOS, Kotlin for Android. Best performance, but you build twice.

Cross-platform

One codebase that runs on both iOS and Android. Cheaper to build; sometimes feels slightly less polished than native.

React Native

Facebook's cross-platform tool. Lets you build iOS and Android apps using React. Powers Instagram, Discord, Shopify's app.

Flutter

Google's cross-platform tool. Build iOS, Android, web, and desktop apps from one codebase. Uses Dart as the language.

Expo

A toolkit on top of React Native that handles a lot of the painful setup. Most React Native apps these days use it.

SwiftUI

Apple's modern way of building iOS interfaces. Less code, more readable, the way new iOS apps are built today.

Jetpack Compose

Android's equivalent to SwiftUI. The modern, recommended way to build Android UIs.

Xamarin

Microsoft's older cross-platform mobile tool. Largely replaced by .NET MAUI now.

MAUI

.NET MAUI

Microsoft's current cross-platform tool for mobile and desktop apps in C#.

Capacitor

A tool that wraps a web app inside a mobile shell so you can ship it to the App Stores. From the team behind Ionic.

Cordova

The original "web app in a phone wrapper" tool. Mostly replaced by Capacitor.

Ionic

A framework for building mobile apps using web tech (HTML, CSS, JavaScript) inside Capacitor.

App Store Connect

Apple's portal for uploading, testing, and publishing iOS apps.

TestFlight

Apple's beta-testing tool. Send your app to a small group before going live on the App Store.

Play Console

Google Play Console

Google's portal for publishing Android apps to the Play Store.

Push notification

A message sent from a server straight to a user's phone, even when the app isn't open.

Deep link

A link that opens a specific screen inside an app instead of the home screen. Tap a product link in an email, land on the product page.

Web Concepts

SSR

Server-Side Rendering

Short for Server-Side Rendering. The page is built on the server and sent to the browser fully ready. Fast first load and great for SEO.

In real life

The waiter brings the plate from the kitchen, fully cooked. You sit down and eat.

CSR

Client-Side Rendering

Short for Client-Side Rendering. The browser gets a near-empty page and JavaScript builds it on the fly. Slower first paint; feels app-like once running.

In real life

The waiter brings raw ingredients. You cook at the table.

SSG

Static Site Generation

Short for Static Site Generation. Pages are built once, ahead of time, and served as plain files. Fast and cheap. Best for content that doesn't change much.

In real life

Meals prepped on Sunday for the week. Heat and serve.

ISR

Incremental Static Regeneration

Short for Incremental Static Regeneration. A Next.js trick — pages are static (fast) but quietly rebuild themselves in the background when content updates.

Hydration

After a server-rendered page loads, JavaScript wakes it up so buttons, menus, and forms work.

In real life

The set is built and dressed; hydration is when the actors walk on stage and start moving.

SPA

Single-Page Application

Short for Single-Page Application. A site that loads once, then swaps content in and out without full page reloads. Feels app-like.

MPA

Multi-Page Application

Short for Multi-Page Application. A traditional site where every link loads a new page from the server. Most marketing sites still work this way.

PWA

Progressive Web App

Short for Progressive Web App. A website that can be "installed" on a phone like an app — works offline, sends push notifications, lives on the home screen.

CDN

Content Delivery Network

Short for Content Delivery Network. A network of servers around the world that serves your site from whichever one is closest to the user. Makes everything faster.

In real life

Corner shops in every neighbourhood instead of one giant warehouse hours away.

Edge

Edge Computing · Edge Functions

Code that runs as close to the user as possible — at the CDN, not in one central server. Lower latency.

Serverless

Code that runs on someone else's infrastructure, only when needed. You don't manage a server. Pay per request.

In real life

An Uber instead of owning a car. It shows up when you need it and disappears after.

Lambda

AWS Lambda

Amazon's serverless service. "A Lambda" usually means a single function that runs on demand.

Cold start

When a serverless function hasn't been used in a while and takes a moment to wake up. The first request feels slow.

Latency

How long a request takes to travel and come back. Measured in milliseconds. Lower is better.

Caching

Saving a copy of something so you don't have to fetch or build it again next time. Makes everything feel faster.

In real life

Keeping the kettle warm so the next cup of tea is ready in seconds.

Cookies

Small bits of data the browser stores for a website. Used to remember logins, baskets, preferences.

Session

The state of a logged-in user across page loads. Sessions are usually tracked with cookies or tokens.

Token

A short string that proves who you are or what you're allowed to do. Sent with requests to skip logging in every time.

DNS

Domain Name System

Short for Domain Name System. The phonebook of the internet. Turns "google.com" into the actual server address (an IP).

HTTPS

HyperText Transfer Protocol Secure

Short for HyperText Transfer Protocol Secure. The encrypted version of HTTP — the padlock in your browser. Non-negotiable in 2026; sites without it get punished.

TLS / SSL

TLS · SSL · Transport Layer Security · Secure Sockets Layer

TLS = Transport Layer Security. SSL = Secure Sockets Layer (the old name). The encryption that makes HTTPS work. People still say "SSL certificate" even though it's been TLS for years.

Domain

Your address on the web — j0e.dev, example.co.uk. You rent it yearly from a registrar.

Subdomain

A prefix on a domain that points somewhere else. blog.example.com is a subdomain of example.com.

Hosting

The service that runs your site on the internet. Without hosting, your domain points to nothing.

VPS

Virtual Private Server

Short for Virtual Private Server. A rented slice of a server you fully control. Cheaper than a dedicated server, more flexible than shared hosting.

IP address

The actual numerical address of a server on the internet. DNS turns names into IPs.

Port

A specific door on a server. Web traffic goes through port 80 (HTTP) or 443 (HTTPS) by default.

Localhost

Your own computer, when running code on it. localhost:3000 is the dev server running on your machine.

Browser

Chrome, Safari, Firefox, Edge. The program that loads and shows websites.

User agent

A label every browser sends saying what it is. Used for analytics and to detect mobile vs. desktop.

Render

To turn code into something you can see on screen. "How long does it take to render?" = how long to draw the page.

DevOps & Hosting

Vercel

A hosting platform built for Next.js (made by the same team). Deploy by pushing to GitHub. This site runs on it.

Netlify

Vercel's main competitor. Same idea — push to GitHub, get a live site.

AWS

Amazon Web Services

Amazon's cloud platform. The biggest in the world. Runs a huge chunk of the internet.

GCP

Google Cloud · Google Cloud Platform

Google's version of AWS. Strong on data, AI, and Kubernetes.

Azure

Microsoft's cloud. Dominant in big enterprise and corporate environments.

Cloudflare

A CDN, security layer, and now a hosting platform. Sits in front of millions of sites and blocks bad traffic.

Heroku

An older platform-as-a-service. Simple to deploy to. Pricier than newer options.

Render

A modern Heroku-style hosting platform. Easy deploys, fair pricing.

Railway

Another modern hosting platform. Loved by indie devs for being fast and friendly.

Fly.io

Fly

A platform that runs your app close to your users around the world. Strong for global apps.

Docker

A way of packaging your app and everything it needs to run into a single "container" that works the same everywhere.

In real life

Sending a meal in its own takeaway box. Same dish whether it's eaten at the restaurant, in the office, or at home.

Kubernetes

K8s

A tool for running and scaling lots of Docker containers across lots of servers. Powerful, complicated, mostly for big systems.

CI/CD

Continuous Integration · Continuous Deployment

CI = Continuous Integration. CD = Continuous Deployment (or Delivery). Automated pipelines that test your code and ship it to production every time you push a change.

In real life

A conveyor belt from your laptop to your live site, with quality checks built in.

GitHub Actions

GitHub's built-in CI/CD. Write a config file, GitHub runs your tests and deploys on every push.

Deployment

Deploy

The act of pushing your code live so users can see it.

Build

The step where source code gets compiled and bundled into the files that actually run in production.

Environment variables

env vars · .env

Settings that change between environments — usually secrets like API keys and database passwords. Never put them in code.

Staging

A near-identical copy of production used for final testing before going live. "Let me check it on staging first."

Production

Prod

The live, real-customers-using-it environment. "It's broken in prod" is the worst sentence in tech.

Rollback

Reverting a deployment back to the previous version when something's gone wrong.

Uptime

The percentage of time your site is up and working. "Three nines" (99.9%) means about 8 hours down per year.

Load balancer

A traffic cop that spreads incoming requests across multiple servers so no single one gets crushed.

Logs

Records of what your app did and when. Where you look first when something breaks.

Monitoring

Tools that watch your app in real time and tell you when things are slow or broken.

Server

A computer that runs your code and answers requests over the internet. Could be a real machine or, more often these days, a slice of one.

AI & Data

AI

Artificial Intelligence

Software that can do tasks normally needing human judgement — writing, image recognition, decision-making.

LLM

Large Language Model

Short for Large Language Model. The kind of AI behind ChatGPT and Claude. Trained on huge amounts of text. Generates writing, code, summaries.

In real life

An incredibly well-read assistant. Knows a lot, occasionally makes things up.

GPT

Generative Pre-trained Transformer

Short for Generative Pre-trained Transformer. OpenAI's family of language models — "GPT-4," "GPT-5" etc. Often used as a general label for ChatGPT-style AI.

Claude

Anthropic's family of AI models. The one writing this guide.

Gemini

Google's family of AI models.

OpenAI

The company behind ChatGPT and the GPT models.

Anthropic

The company behind Claude.

Prompt

What you type into an AI to get a response. "Write me a marketing email" is a prompt.

Token

How AI models count text — roughly a chunk of word. AI usage is billed and limited per token.

Embedding

Turning a piece of text into a list of numbers that represents its meaning. Used for search and "find similar" features.

Vector database

A database built to store and search embeddings — find the closest match in meaning, not just keywords.

RAG

Retrieval-Augmented Generation

Short for Retrieval-Augmented Generation. Giving an AI access to your own documents so it answers based on them, not just its training data.

In real life

Letting the assistant grab a folder of your notes before answering, instead of going off memory alone.

Fine-tuning

Taking a general AI model and training it further on your own specific data to make it better at one job.

Training

The process of teaching an AI model by showing it huge amounts of data. Done once, can take months and cost millions.

Inference

The act of using a trained AI to generate an answer. Every time you send a prompt, that's inference.

Hallucination

When an AI confidently makes something up — a fake citation, a wrong fact. The biggest weakness of LLMs.

Agent

An AI that can take actions, not just chat — search the web, edit files, call APIs, run tools on your behalf.

MCP

Model Context Protocol

Short for Model Context Protocol. A standard way to plug tools and data sources into AI agents. Lets Claude or ChatGPT talk to your apps in a structured way.

Multimodal

An AI that handles more than just text — also images, audio, video.

Machine learning

The broader field AI sits inside. Software that learns patterns from data instead of being explicitly programmed.

Neural network

The structure inside most modern AI. Loosely inspired by how brain cells connect.

Dataset

A collection of data used to train or test a model.

Big data

Datasets so large they need special tools to process. The buzzword peaked in 2015; the work is still everywhere.

ETL

Extract, Transform, Load

Short for Extract, Transform, Load. The pipeline of pulling data out of one system, cleaning it up, and loading it somewhere else for analysis.

Data warehouse

A massive central database for analytics — Snowflake, BigQuery, Redshift. Different beast from the database your app uses.

Design & UX

UI

User Interface

What the user sees and clicks — buttons, layouts, forms, colours.

UX

User Experience

How the whole product feels to use. Easy or frustrating, fast or sluggish, clear or confusing. Bigger than just looks.

Figma

The design tool every modern team uses. Where mockups, design systems, and prototypes get made before code.

Wireframe

A rough black-and-white sketch of a page's layout — boxes and labels, no colours, no polish. Used early.

Mockup

A polished, full-colour design of what a page will look like. Static — doesn't actually do anything yet.

Prototype

A clickable version of a mockup. Looks real, links work, but no real data or backend behind it.

Design system

A documented set of components, colours, and rules so every page looks like it belongs to the same product.

In real life

A brand bible. Everyone working on the product follows the same recipe.

Component

A reusable piece of UI — a button, a card, a navbar. Build it once, use it everywhere.

Accessibility

a11y

Making sure your site works for everyone — screen readers, keyboard-only users, low vision, colour blindness. Also a legal requirement in many places.

Contrast

How much the text stands out from the background. Too low and lots of people genuinely can't read it.

Semantic HTML

Using the right HTML element for the job — <button> for buttons, <nav> for navigation. Helps screen readers, SEO, and your future self.

ARIA

Extra labels in HTML that help screen readers describe parts of a page that aren't obvious from the visuals.

Responsive design

A layout that adapts to whatever screen it's on — phone, tablet, desktop. Bare minimum these days.

Mobile-first

Designing for phones before desktop, since most traffic is mobile.

Breakpoint

A screen size where the layout changes — e.g. switching from a one-column phone view to a three-column desktop view.

Above the fold

What the user sees on a page before scrolling. The most valuable real estate on any site.

Hero section

The big top section on a homepage — usually a headline, subline, and call to action.

Skeleton loader

Grey placeholder shapes that show while content is loading. Feels faster than a blank screen or a spinner.

Microinteraction

Small UI moments — a button pressing, a heart filling in, a checkbox bouncing. Adds polish.

Business, SEO & Acronyms

SEO

Search Engine Optimisation

Short for Search Engine Optimisation. Getting your site to rank higher on Google. A mix of fast loading, good content, clean code, and links from other sites.

SERP

Search Engine Results Page

Short for Search Engine Results Page. The page Google shows after a search. The whole game in SEO is getting onto page one of the SERP.

Meta tags

Bits of info in your HTML that don't show on the page but tell Google and social media how to display it.

OpenGraph

OG tags

The meta tags that control how your link looks when shared on social — title, description, preview image.

Sitemap

A file listing every page on your site so Google can crawl it efficiently.

robots.txt

A small file telling search engines which parts of your site they can and can't look at.

Schema.org

Structured data · JSON-LD

Extra hidden info you add to a page so Google understands what's on it — articles, products, reviews, businesses.

Backlink

A link from another site to yours. The single biggest signal Google uses to decide who's trustworthy.

Anchor text

The clickable words in a link. "Click here" tells Google nothing; "London plumber" tells it a lot.

Keyword

A word or phrase people search for. Pick the right ones and your site gets found.

Long-tail keyword

A specific, multi-word phrase. Less traffic per keyword, but the people searching it actually want what you sell.

Alt text

A short description of an image. Read by screen readers, used by Google, shown when an image fails to load.

Lighthouse

A free tool from Google that scores your site on speed, accessibility, SEO, and best practices.

Core Web Vitals

Three speed metrics Google uses to judge your site. Score badly and you rank lower.

LCP

Largest Contentful Paint

Short for Largest Contentful Paint. How long until the biggest thing on your page (usually the hero image or headline) shows up. Should be under 2.5s.

FID

First Input Delay

Short for First Input Delay. How long until the page actually responds when you click something. Being replaced by a metric called INP.

INP

Interaction to Next Paint

Short for Interaction to Next Paint. How quickly the page reacts to clicks and taps. Replaces FID. Should feel instant, under 200ms.

CLS

Cumulative Layout Shift

Short for Cumulative Layout Shift. How much things jump around as the page loads. Buttons moving as you go to click them = high CLS = bad.

Conversion rate

The percentage of visitors who do the thing you want — buy, sign up, contact you. The number that actually matters.

CTA

Call To Action

Short for Call To Action. The button or link telling people what to do next. "Get a quote," "WhatsApp me," "Buy now."

A/B test

Split test

Showing version A to half your users and version B to the other half, then keeping whichever wins. Removes guesswork.

Funnel

The journey from "never heard of you" to "paying customer." Each step loses some people; the funnel narrows.

Lead

Lead generation · Lead gen

A potential customer who's shown interest — filled in a form, sent a WhatsApp, joined a list. Lead gen is getting more of those.

MVP

Minimum Viable Product

Short for Minimum Viable Product. The smallest version of your product that's actually useful. Ship that, learn, then add more.

In real life

Open the chippy with chips and a fryer. Add the kebabs once people are coming through the door.

KPI

Key Performance Indicator

Short for Key Performance Indicator. The metrics you actually track — revenue, signups, retention. The numbers that tell you if you're winning.

ROI

Return On Investment

Short for Return On Investment. What you get back for what you put in. Spent £500 on ads, made £2,000 in sales — strong ROI.

SaaS

Software as a Service

Short for Software as a Service. Software you rent monthly instead of buying once. Notion, Slack, Spotify. The dominant model in software.

B2B / B2C

B2B · B2C

Business-to-business (selling to companies) vs. business-to-consumer (selling to people). Two very different games.

Churn

The rate at which paying customers leave. High churn kills SaaS businesses faster than anything.

LTV

Customer Lifetime Value · CLV

Short for Customer Lifetime Value (sometimes CLV). How much a customer is worth to you in total over the time they stay.

CAC

Customer Acquisition Cost

Short for Customer Acquisition Cost. What it costs you to get one new customer. If CAC is bigger than LTV, you're losing money on every sale.

Bounce rate

The percentage of visitors who land on a page and immediately leave without doing anything.

Security

XSS

Cross-Site Scripting

Short for Cross-Site Scripting. An attack where bad code is sneaked into a page and runs in your visitors' browsers. Prevented by sanitising user input.

CSRF

Cross-Site Request Forgery

Short for Cross-Site Request Forgery. An attack where a user is tricked into making a request they didn't mean to, like submitting a hidden form on a dodgy site.

SQL injection

An attack where someone types SQL into a form field and tricks your database into running it. Easy to prevent; embarrassing if you don't.

CAPTCHA

The "I'm not a robot" check on forms. Stops bots from spamming you.

Brute force

An attack where bots try millions of password combinations until one works. Rate limiting and 2FA shut this down.

Encryption

Scrambling data so only the right key can unlock it. What HTTPS does to your traffic.

In real life

Sending a letter in a sealed safe instead of a postcard.

Hashing

A one-way scramble. You can hash a password but never un-hash it. That's why a proper site never "recovers" your password — it resets it.

In real life

Mincing meat. Easy to mince a steak; impossible to un-mince it back into one.

Salt

A random string added to a password before hashing, so two people with the same password get different hashes. Stops bulk attacks.

2FA / MFA

Two-Factor Authentication · Multi-Factor Authentication

Logging in with more than just a password — usually a code from your phone too. Turn it on everywhere.

Zero-trust

A security model that assumes no request is safe by default — every action gets verified, even from inside your network.

GDPR

General Data Protection Regulation

Short for General Data Protection Regulation. European data protection law. If you collect data from EU/UK users, you've got rules to follow about consent, storage, and deletion.

Cookie banner

The "accept cookies" pop-up. Required by GDPR and similar laws. Don't pre-tick the boxes.

Penetration test

Pen test

Hiring someone to legally try to hack your system and report back what they found. Standard for serious products.

Firewall

A filter sitting in front of your servers, blocking traffic that shouldn't be there.

DDoS

Distributed Denial of Service

Short for Distributed Denial of Service. An attack where thousands of bots flood your site with fake traffic to take it offline. Cloudflare and similar services help block these.

Tools & Workflow

Git

The version-control tool every dev uses. Tracks every change to a codebase so you can go back, branch off, and merge work together.

In real life

Track changes in Word, but for entire projects, with a full history forever.

GitHub

The biggest place to host code with Git. Where most modern open-source and team projects live.

GitLab

A GitHub competitor. Often used by companies who want to self-host their code.

Bitbucket

Atlassian's GitHub competitor. Common in teams already using Jira and Confluence.

Repository

Repo

A project's codebase plus its full history. "Push to the repo" = save your changes to the shared project.

Branch

A separate line of work in a project. You branch off, do your changes, then merge back when ready.

Commit

A saved snapshot of changes with a message. The unit of work in Git.

Merge

Combining one branch into another. Usually when a feature is finished and going back into the main project.

Pull request

PR · Merge request · MR

A request to merge your branch into the main one, usually reviewed by another dev first. Where most code review happens.

Rebase

Replaying your commits on top of the latest main branch. Keeps history tidier than merging.

Fork

Your own copy of someone else's repository. The starting point for contributing to open-source projects.

Clone

Downloading a copy of a repository to your local machine.

npm

Node Package Manager

Short for Node Package Manager. The package manager for JavaScript. Where you install libraries (React, Express, anything).

yarn

An alternative to npm. Same job, originally made by Facebook.

pnpm

A faster, more disk-efficient alternative to npm. Used in this project.

Bun

A new, very fast all-in-one tool for JavaScript — runtime, package manager, bundler. Trying to replace Node + npm.

package.json

The file at the root of every Node.js project listing dependencies and scripts.

Dependency

A library your project relies on. "It depends on React" = React must be installed for it to work.

Semver

Semantic Versioning

The 1.2.3 versioning system. Big number = breaking changes, middle = new features, last = bug fixes.

Monorepo

Keeping multiple projects in a single repository. Big at companies like Google, Meta, and Vercel.

IDE

Integrated Development Environment

Short for Integrated Development Environment. The program devs write code in. Has a text editor plus tools for running, debugging, and version control built in.

VS Code

Visual Studio Code · VSCode

Microsoft's free code editor. The most popular IDE in the world.

Cursor

A fork of VS Code with deep AI integration baked in. Popular among devs in 2026.

Terminal

Command line · CLI

The black window where devs type commands instead of clicking buttons. Faster for almost everything once you know it.

Linter

A tool that scans your code for likely mistakes and style problems before you even run it.

Formatter

A tool that auto-tidies your code — spaces, line breaks, indentation. So no one argues about style.

ESLint

The standard linter for JavaScript and TypeScript.

Prettier

The most popular code formatter for web tech.

Unit test

A small test that checks one tiny piece of code in isolation. Fast to run; the foundation of testing.

Integration test

A test that checks several pieces working together — your code plus a database, for example.

End-to-end test

e2e

A test that drives the whole app like a real user would — clicks buttons, fills forms, checks the result.

Jest

A popular JavaScript test runner, originally from Facebook.

Vitest

A modern, faster Jest alternative built on top of Vite.

Playwright

Microsoft's tool for end-to-end testing — drives a real browser like a user would.

Cypress

Another end-to-end testing tool, very popular before Playwright caught up.

Refactor

Changing the code's structure without changing what it does. Cleaning up.

Tech debt

Technical debt

Shortcuts taken to ship faster that you'll have to pay back later. Some is fine; too much slows everything down.

Codebase

The full set of code that makes up a project.

Open source

Code anyone can read, use, and contribute to. React, Linux, Postgres are all open source.

Bug

Something in the code doing what it wasn't meant to do. Every codebase has them.

Hotfix

An urgent fix shipped straight to production because something is on fire.

Stack

Tech stack

The full list of tools, languages, and frameworks a product is built on. "What's your stack?"

Frontend

Front-end

Everything the user actually sees and clicks — the browser side.

Backend

Back-end

The server side. Database, business logic, the bits the user never sees directly.

Full-stack

A dev who handles both frontend and backend. What I do.

DevOps

The discipline of getting code from a dev's laptop to running in production reliably. Servers, deployments, monitoring.

Pair programming

Two devs working on the same code at the same time. One drives, one navigates.

Standup

A short daily team meeting. What I did yesterday, what I'm doing today, what's blocking me.

Sprint

A short, fixed chunk of work — usually 1 or 2 weeks. Common in agile teams.

Agile

A way of building software in short cycles, adjusting as you learn, instead of planning everything upfront.

Scrum

A specific flavour of agile with sprints, standups, and defined roles. Loved by some, hated by others.

Backlog

The list of features and bugs waiting to be worked on.

Ticket

Issue

A single unit of work — a feature, a bug, a task. Tracked in tools like Jira, Linear, or GitHub Issues.

Jira

Atlassian's ticket-tracking tool. Common in big teams. Powerful and famously fiddly.

Linear

A modern, fast Jira competitor loved by startups.

Slack

Team chat. Where most modern companies actually communicate.

Code review

Another dev reading your changes before they merge in. Catches bugs and shares knowledge.

Documentation

Docs

Written guides for how a system works. Future-you will thank past-you for writing them.

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