Glossary

Every technical word used on LogicTrail, explained in one or two plain sentences. No coding knowledge needed.

AI coding agent
An AI tool that doesn't just suggest code but runs commands, edits files and installs things for you.
API
The part of an app that other programs talk to. Your app's pages ask its API for data, like a waiter taking orders to a kitchen.
Authentication
Checking who someone is, usually by signing in.
Authorization
Checking what someone is allowed to do once you know who they are. Signed in does not mean allowed.
Backup
A saved copy of your data from a moment in time, so you can get it back after a mistake.
Browser
Chrome, Safari and friends. Everything that runs here is visible to, and changeable by, the person using it.
Bundle
The code files your website sends to every visitor's browser. Anyone can open and read them.
Cache
A saved copy of a page or data, reused to be fast. Until refreshed, it can show old information.
Connection pooler
A middleman that lets many requests share a few database connections, because databases accept only a limited number.
CORS
A browser safety rule: a website may only read replies from another site's API if that API says it's allowed.
Crawler
A program that visits websites automatically, for search engines, AI training, or abuse.
Cron job
Work that runs on a schedule or in the background, instead of while someone waits for a page.
Database
Where your app keeps its data, organised in tables, like a set of spreadsheets.
Deploy
Putting a new version of your app online so users get it.
Diff
A view of exactly what changed in the code: lines added in green, lines removed in red.
Egress
Data sent out of a service, such as images downloaded from your storage. Many services bill for it.
Endpoint
One specific address on your server that does one job, like /api/invoices. Each one needs its own safety checks.
Environment variable
A setting stored outside your code, like a secret key. Your laptop and your live site each have their own copy.
Force push
Overwriting the online copy of your code's history with your local one, which can erase other work.
Git, commit, repository
Git saves snapshots (commits) of your code in a repository, so you can see history and go back.
Grant
Permission for a type of user to use a table at all. Without it you get 'permission denied', before any row rules are checked.
Idempotency key
A unique label for one action, so if it is sent twice it still only happens once.
IDOR
A bug where changing an id in an address (105 instead of 104) shows someone else's data, because the app never checks the owner.
Index
Like a book's index: it lets the database jump straight to the rows it needs instead of reading every one.
localhost
An address that always means 'this computer'. It works on your laptop and nowhere else.
Lockfile
A file that pins the exact versions of every package, so installs don't change silently.
MCP
A way to plug tools, like your database, into an AI assistant so it can use them directly.
Middleware / proxy
Code that runs before every page loads, often to redirect signed-out visitors. Useful, but not enough on its own.
Migration
A script that changes the shape of your database, such as adding or removing a column. Some changes delete data forever.
Network tab
A panel in your browser's developer tools that lists every request your page makes and every reply.
OAuth
The 'Sign in with Google' system. Google sends people back to your app only at addresses you registered.
Package
Code someone else wrote that your app installs and uses. Installing it runs their code on your machine.
Point-in-time recovery
A kind of backup that can rewind your database to any minute, not just last night.
Policy
One rule in Row Level Security, such as 'people can read only their own orders'.
Production
The real, live version of your app that customers use, as opposed to the copy on your laptop.
Prompt injection
Hidden instructions inside text an AI reads, like a support ticket, that trick it into doing something you didn't ask.
Public (publishable) key
A key that is meant to be in your website. It is safe only when database rules decide what it can do.
Public prefix
Starting a setting's name with NEXT_PUBLIC_ or VITE_ copies its value into your website, where anyone can read it.
Query
A question your app asks the database, such as 'give me all orders for this customer'.
Rate limit
A cap on how often someone may do something, like 10 requests a minute, to stop abuse and runaway bills.
Request
A message your browser (or any program) sends to a server asking for something: 'give me invoice 105' or 'save this profile'.
Response
The server's reply to a request: the data, plus a status code saying whether it worked.
Row Level Security (RLS)
Database rules that decide which rows each user may see or change. With it off, anyone with your public key can read everything.
Secret key
A password your app uses to talk to a paid service. Anyone who sees it can use it, and spend your money.
Server
A computer that runs your app's code out of sight. Users can't change what happens there, which is why checks belong there.
Serverless function
A piece of server code that starts for each request and stops soon after. You pay per use, and it has time and size limits.
Session
The app's memory that you are signed in, kept for a while so you don't log in on every page.
Signed URL
A temporary link to a private file that stops working after a few minutes.
SMTP / email provider
The service that actually sends your app's emails. Built-in test senders are not meant for real users.
SPF, DKIM, DMARC
Settings on your domain that prove emails really come from you, so they don't land in spam.
Status code
A three-digit number on every response. 200s mean it worked, 400s mean the request was wrong or not allowed, 500s mean the server broke.
Storage bucket
A folder in the cloud for files like images and PDFs. It has its own permissions, separate from the database.
Stripe
A popular payments service. It charges cards and tells your app what happened through webhooks.
Supabase
A popular hosted database with sign-in and file storage built in. Many AI app builders use it behind the scenes.
Table, row, column
A table is like one spreadsheet (orders). Each row is one item (one order); each column is one detail (price, date).
Timeout
A maximum time something may take before it is stopped.
Token
A temporary pass that proves who you are. Access tokens expire quickly; a refresh token quietly gets a new one.
UTC and time zones
UTC is one world clock. Save times in it, then convert to each person's local time only when showing them.
Webhook
A message another service (like Stripe) sends to your server to say something happened, such as 'this customer paid'.
XSS
When a site shows text from users as live code, so one person's message can run in everyone else's browser.