Tech words in plain English
The tech words you'll hear when you start building software with AI, each explained in a few plain sentences with an everyday comparison. No jargon needed to read them.
AI agent
An AI agent is an AI assistant that can take actions, not just answer questions. A coding agent such as Claude Code, Codex or Cursor can read files, write code and run commands to get a job done, checking its own work as it goes. It's the difference between someone who tells you how to fix the tap and someone who fixes it.
API
An API is the way one piece of software asks another for something. When your accounting system shows your bank transactions, it got them through the bank's API. Think of it as a counter with a menu: you ask for what's on the menu, in the way the menu says, and you get it back.
Backup
A backup is a copy of your information kept somewhere else, so you can get it back if the original is lost or damaged. A backup only counts if you can restore it, so good systems test that regularly. It's the spare key you keep at a neighbour's, not the one on the same keyring.
Bug
A bug is a mistake in software that makes it do something it shouldn't. Most bugs are small, like a total that's off by a cent, but some stop an app working entirely. Engineers called faults bugs long before computers, but the most famous one was a real moth found stuck inside a computer in 1947.
Cache
A cache is a quick-to-reach copy of something that's slow to fetch, kept nearby so it doesn't have to be fetched every time. Your browser caches pictures from websites you visit so they load faster next time. It's like keeping the milk in the fridge door instead of going to the shop for every cup of tea.
The cloud
The cloud is other people's computers, rented over the internet. When your files are "in the cloud", they're stored on servers in a large building somewhere, run by a company like Google, Microsoft or Amazon. You don't see the machines, but they're real, and they have an address.
Database
A database is where an app keeps its information, set out so many people can use it at once without mixing things up. Unlike a spreadsheet, it has rules: a date column only takes dates, and every job must belong to a real customer. It's a filing cabinet with a librarian who won't let you put anything in the wrong drawer.
Deploying
Deploying means taking an app from the computer it was built on and putting it somewhere people can use it, usually a server on the internet. Each time you change the app, you deploy the new version. It's like moving a new process from a trial run to the whole team.
Encryption
Encryption scrambles information so only someone with the right key can read it. A web address starting with https means the connection to that site is encrypted, so nobody in between can read what you send. It's a letter in a locked box rather than on a postcard.
Open source
Open source software is software whose code anyone can read, use and change, under terms that say how. Much of the internet runs on it, including most web servers and databases. Think of a recipe that's published for anyone to cook, rather than a secret one.
Prompt
A prompt is what you type to tell an AI assistant what you want. The clearer the prompt, the better the result: say who it's for, what it should do and what it shouldn't. It's a brief, the same as you'd give a new staff member.
SaaS
SaaS, short for software as a service, is software you rent by the month and use in a browser instead of installing it. Xero, Slack and Google Workspace are all SaaS. You don't own it, and when you stop paying, you stop using it.
Server
A server is a computer that's always on and connected to the internet, waiting for requests. When you open a website, a server somewhere sends you the page. Your laptop could be one, until you close the lid.
Two-factor authentication
Two-factor authentication means proving it's you in two different ways when you sign in, usually a password plus a code from your phone. If someone steals your password, they still can't get in without your phone. It's a door with two locks, each needing a different key.
Uptime
Uptime is how much of the time a system is working and available. It's usually given as a percentage: 99.9% uptime still allows about 43 minutes of downtime a month. It's like a shop's opening hours, except the promise is to never close.