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Ship Like Crazy
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Glossary 📖

122 terms, in plain English.

A

Acceptance criteria Ch 10
Checkable statements that say when a feature is done, such as 'customers cannot add a sold-out item to their order'.
Accessibility Ch 3
Making software usable by everyone, including people with low vision, colour blindness, limited movement or a screen reader.
Agent Ch 1
An AI that loops: plan, use a tool (read a file, run a command), look at the result, decide the next step, until the job is done.
API
A fixed, agreed way for two pieces of software to talk: one sends a request, the other sends back a response.
API key Ch 5
A code that identifies your app to another service's API. Publishable keys can be public; secret keys must stay on the server.
Auth (authentication and authorisation)
Authentication checks who you are, like logging in. Authorisation decides what you're allowed to see or change once you're in.
Authentication Ch 6
Proving who you are, usually by signing in. Gita checking your booking at the door.
Authorisation Ch 6
Deciding what a signed-in person is allowed to do, such as seeing only their own orders.

B

Backend-as-a-service Ch 4
A ready-made backend you rent, with a database, logins, file storage and rules included. Supabase, Firebase and Convex are examples.
Branch Ch 2
A parallel line of commits in Git, used to try changes without touching the main version until you're ready to merge them.

C

CI (continuous integration) Ch 10
A service that runs your lint and tests on a server every time code is pushed, so problems are caught even when someone skips them locally.
CLAUDE.md Ch 10
A short text file in your repo that Claude Code reads at the start of every session: stack, commands, conventions, a never-do list and where the docs live. It's advice Claude usually follows, not a guarantee.
Client Ch 4
The user's device and browser, which download and run your app's pages. The user fully controls it, so it can't be trusted with secrets or decisions about money.
Code editor Ch 2
An app for viewing and editing a project's files, with a file sidebar and a built-in terminal. VS Code and Cursor are code editors.
Commit Ch 2
A save point in Git: a snapshot of every file in your project, with a short message describing the change.
Component Ch 3
A reusable building block of a UI, such as a button, card or drawer, built once and used many times.
Composite index Ch 9
An index on several columns in a set order. It helps queries that filter on those columns starting from the left.
Connection pooling Ch 9
Sharing a small number of real database connections among many app instances, so a traffic spike doesn't exhaust the database.
Context window Ch 1
Everything the model can see right now: your prompt, files it has read, its notes. It knows nothing about your project outside it.
Contrast Ch 3
How much text stands out from its background. Normal text should have a contrast ratio of at least 4.5:1 to be readable.
Cron job Ch 4
A task that runs automatically on a schedule, like sending a daily sales email at 9 pm.
CSRF (cross-site request forgery) Ch 6
A trick where another website makes a signed-in user's browser send an unwanted request to your app. Frameworks and cookie settings protect against it.
curl Ch 5
A command-line tool for sending HTTP requests by hand and seeing the raw response. Handy for testing APIs.
Cursor pagination Ch 9
Loading the next page by asking for rows after the last one you saw, instead of skipping a count of rows. Stays fast on huge tables.

D

Database
Organised storage where your app keeps and finds its data, like orders, customers and loyalty points.
Deployment Ch 2
Putting your code on a server so it runs on the internet. With Vercel, every push to GitHub can deploy automatically.
Design system Ch 3
A written set of design decisions (colours, fonts, spacing, components) that keeps every screen consistent.
Design token Ch 12
A named design value, like color-primary or space-4, that every component uses, so changing it once updates every screen.
DevTools Ch 3
Developer tools built into every browser that show a page's code and let you inspect and edit your own copy of it live.
Diff Ch 10
The exact list of changes between two versions of your code: lines added, removed and changed.
DNS Ch 2
The internet's phone book. It maps a domain name like meerascorner.in to the address of the server that hosts the site.
Doom loop Ch 10
A coding session where each fix breaks something else, the changes keep growing and nobody can see the whole picture any more. The way out is to stop, revert and start a smaller, sharper session.

E

Edge function Ch 4
A serverless function that runs in data centres close to each user, for speed. Supabase Edge Functions and Cloudflare Workers are examples.
Embeddings Ch 11
Lists of numbers that represent the meaning of a piece of text, so similar texts end up close together and can be found or grouped.
Endpoint Ch 5
One specific API address that does one job, like https://queueless.app/api/orders.
Environment variable Ch 4
A named value, like an API key, that your app reads when it runs instead of storing it in the code. Locally it lives in .env.local; in production, in your host's settings.
ER diagram Ch 7
An entity-relationship diagram: a picture of your tables and the lines showing how they point at each other.

F

Firebase Security Rules Ch 6
Firebase's rules that decide who can read or write each document in Firestore or file in Cloud Storage. Firebase's equivalent of RLS.
Foreign key Ch 7
A column that holds another table's primary key, so a row can point at a row elsewhere instead of copying its data.
Framework Ch 2
A ready-made structure for an app that decides where things go; you fill in the parts. Next.js is a framework.

G

Git Ch 2
A tool that records the history of your project as a series of save points (commits) you can return to at any time.

H

Hook Ch 10
A command Claude Code runs automatically at a set moment, like after every file edit. Unlike CLAUDE.md, hooks run every time, so use them for things that must never be skipped.
HTTP Ch 5
The language browsers and servers use to send requests and responses over the web. Most APIs speak it too.
HTTP header Ch 5
A short label sent with a request or response, such as the content type or an Authorization token proving who is asking.
HTTP method Ch 5
The verb of a request: GET reads, POST creates, PUT or PATCH updates, DELETE removes.

I

Idea brief Ch 12
A one-page document with the problem, evidence, proposed solution, positioning and risks. It's the first file in the idea-to-ship process.
IDOR (insecure direct object reference) Ch 6
A flaw where the server returns a record by its ID without checking that it belongs to the person asking.
Index Ch 9
A sorted lookup structure kept beside a table so the database can jump to matching rows instead of reading every row.

J

Jobs-to-be-done Ch 12
A way of describing what someone is really trying to achieve when they use a product, such as 'get my chai before the bus' rather than 'use an ordering app'.
Join Ch 9
A SQL operation that combines rows from two or more tables in one query, matching them on a shared column.
Join table Ch 7
A table in the middle of a many-to-many relationship, with a foreign key to each side, like order_items between orders and menu items.
JSON Ch 5
A simple text format for data, made of names and values inside curly braces. Most APIs send and receive it.

L

Layout Ch 3
Where things sit on a screen: header, content, sidebars, a bar fixed to the bottom.
Least privilege Ch 6
Giving each person or program the smallest access it needs to do its job, and nothing more.
Ledger Ch 11
An append-only list of changes, like points earned and spent. You never edit a balance; you add a row, and the balance is the sum.
Library Ch 2
A box of ready-made code you call when you need it, such as a set of buttons or a date formatter.
LLM (large language model) Ch 1
An AI model trained on huge amounts of text and code that predicts the next piece of text. Claude is one.
Localhost Ch 2
The address of your own computer. An app at localhost:3000 is running on your machine, and only you can see it.

M

MCP (Model Context Protocol) Ch 5
An open standard that lets AI agents like Claude use outside tools and data, such as your database or GitHub, in a consistent way.
Migration Ch 11
A saved file of database changes (like creating a table) that runs in order, so every copy of your database ends up with the same structure.
Mockup Ch 12
A realistic picture of a screen, made before any code, so people can react to it and you can change your mind cheaply.
Monolith Ch 4
One app that holds the pages, server code and logic together and is deployed as a single unit. The simplest setup, and the right one for most first apps.
Multi-tenancy Ch 11
One app and one database serving many customers (here, cafés), where every row records which customer it belongs to and each one sees only their own data.

N

N+1 query Ch 9
Loading a list with one query, then running one more query for each item in it. Fixed with a join or one batched query.
Native app Ch 3
An app installed from the App Store or Play Store, built for the phone platform (Swift, Kotlin) or with cross-platform tools like Expo or Flutter.
Normalisation Ch 9
Storing each fact in exactly one place, and linking to it from elsewhere, so copies can't drift out of date.
NoSQL Ch 7
Databases that don't use tables, such as document stores (Firestore, MongoDB) and key-value stores (Redis). Easy to start, harder to query and keep consistent.

O

OAuth Ch 6
The standard behind buttons like 'Sign in with Google': another service confirms who you are and tells your app.
Object storage Ch 7
Storage for files like images and PDFs, such as Supabase Storage or Amazon S3. The database keeps only the file's path.
ORM Ch 7
A library like Prisma or Drizzle that lets you write database queries as ordinary code and translates them into SQL.

P

Package Ch 2
Code someone has published for others to install, usually from the npm registry. Your package.json lists the ones your app uses.
Passkey Ch 6
A sign-in key stored on your phone or laptop and unlocked with your fingerprint, face or PIN. No password to steal.
Plan Mode Ch 11
A Claude Code mode (Shift+Tab twice) where Claude explores your code and writes a plan without editing any files, so you can correct it first.
Point-in-time recovery (PITR) Ch 9
Restoring a database to its exact state at a chosen moment, such as one minute before a bad delete.
Policy Ch 6
One RLS rule that allows a specific action (read, insert, update, delete) on a table, for specific users and rows.
Postgres (PostgreSQL) Ch 8
A free, open-source relational database that stores data in tables and answers questions in SQL. Decades old, very reliable.
Primary key Ch 7
A column whose value uniquely identifies each row in a table and never changes, usually called id.
Production Ch 2
The live version of your app, running on a server on the internet for real users.
Prototype Ch 12
Mockups linked together so you can tap through a flow as if it were a real app, used to test with real users before building.
Publishable key (anon key) Ch 6
Supabase's public key that browser code uses to reach your database. It's safe only when row-level security restricts what each user can do.
PWA (progressive web app) Ch 3
A web app that can be added to a phone's home screen and open full-screen like an app, without an app store.

R

Rate limit Ch 6
A cap on how many requests one person or address can make in a period, such as 10 per minute. Stops password guessing and runaway bills.
Realtime Ch 11
A way for the database to push changes to open browsers as they happen, so pages update without a refresh.
Relational database Ch 7
A database that stores data in tables of rows and typed columns, linked by keys. Postgres, which Supabase runs, is one.
Repository (repo) Ch 2
A project folder together with its full Git history. GitHub stores copies of repositories online.
Responsive design Ch 3
Layouts that adapt to the screen size, usually designed for phones first and then spread out for larger screens.
Role Ch 6
A kind of user with a set of permissions, such as customer, barista or owner.
Route handler Ch 4
In Next.js, a file such as app/api/orders/route.ts that answers web requests to that path on the server.
Row Level Security (RLS) Ch 11
A Postgres feature that checks every read and write against policies, so each user only reaches the rows they're allowed to.

S

Schema Ch 9
The plan of a database: which tables exist, their columns and types, and how they link together.
Secret key Ch 4
A password your app uses to talk to another service, like Stripe or an AI API. Whoever has it can spend your money or read your data, so it stays on the server.
Server Ch 4
A computer you control, usually rented in the cloud, that runs the parts of your app users mustn't touch: prices, permissions, secrets and data.
Server action Ch 4
In Next.js, a function marked "use server" that your page can call but that only ever runs on the server. Under the hood it's a public endpoint, so it must check its inputs.
Serverless function Ch 4
A small piece of server code that wakes up to handle a request and then sleeps. It still runs on a server; you just never manage it.
Session Ch 6
A record on the server that you've signed in, referenced by an ID stored in a browser cookie. Like a numbered wristband the café keeps a list of.
Skill Ch 10
A folder of instructions for a procedure you repeat, which Claude loads when the job matches or when you call it with a slash command.
Slice Ch 10
One small, user-visible change you can build, check in a browser and commit in a single session.
Soft delete Ch 9
Hiding a row by setting a deleted_at time instead of removing it, so it can be restored or kept for records.
Spec (specification) Ch 12
A document describing what a product does, for whom, and how you'll know it works, without describing the code. Claude builds from it.
SQL Ch 7
The language for reading and changing data in a relational database, with statements like SELECT, INSERT, UPDATE, DELETE and JOIN.
Stack trace Ch 2
The list of files and line numbers printed with an error, showing the path the code took before it failed. The first line says what went wrong; the rest say where.
Status code Ch 5
The three-digit number at the top of every HTTP response. 2xx means it worked, 4xx means the request was wrong, 5xx means the server failed.
Subagent Ch 10
A separate Claude with its own instructions, tools and a fresh context, which your main session hands a focused job (like a security review) and gets a report back from.
Supabase Ch 8
A hosted Postgres database with auth, file storage, realtime updates and server functions built around it. The backend this book uses.
Surface Ch 3
A place where a UI lives: a website, web app, mobile app, desktop app, watch or chat.

T

Terminal Ch 2
A text window where you type commands instead of clicking. It runs exactly what you type and prints what happened.
Token Ch 1
A small chunk of text (a word or part of one) that a language model reads and predicts, one at a time.
Token (JWT) Ch 6
A signed, tamper-proof piece of text that says who you are and when it expires. The server checks the signature instead of looking you up in a list.
Transaction Ch 7
A group of database changes that either all happen or none do, so a crash halfway can't leave things half-done.

U

UI (user interface)
Everything a person sees and taps in an app: screens, menus, buttons and forms.
UI states Ch 3
The different versions of a screen depending on what's happening: empty, loading, error and success.
User story Ch 12
One sentence in the form 'as a [user], I want [action], so that [benefit]', followed by acceptance criteria.

V

Validation Ch 12
Collecting evidence, from behaviour rather than opinions, that real people have a problem and would pay to solve it, before you build.
Vendor lock-in Ch 8
When your app depends so deeply on one company's tools that moving to another would be slow, costly or risky.
Vibe coding Ch 1
Building software by describing what you want in plain language and letting an AI write, run and fix the code, while you steer by judging the result.
Visual hierarchy Ch 3
Arranging a screen so the most important things are the most noticeable, using size, weight, colour and position.

W

Webhook Ch 11
A message another service (like Stripe) sends to your server when something happens, such as a payment succeeding. Verify its signature before trusting it.
Webhook signature Ch 5
A code the sending service attaches to each webhook using a shared secret. Your server checks it to prove the webhook is genuine before acting on it.
Worktree Ch 10
A second working copy of your repo folder that shares the same Git history, so two agents can work on different branches without touching each other's files.