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Build Your
App.

For people who don't write code. Drop one folder onto your computer, open it in Claude Code or Codex and say "Let's build my app." I'm not a developer, and I build with these tools myself. This is the method and the guard rails, with 23 guides.

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Instant download · Works, or your money back · Secure checkout with Stripe

Buy on your phone, set up on your computer. The booklet reads anywhere.

  • £20 once
  • Works with Claude Code or Codex
  • Yours to keep
  • No subscription
Build Your App

I run a barber's. I want customers to book online and pay a deposit. I've never written code.

You won't need to. First we write one page: who books, the one job the app does, and five features at most, each with a check you can try by hand.

Then what?

Then we set up your computer together, one step at a time. You give the coding agent one small job, we read its plan before you say yes, you try it, and we save it. Payments stay in test mode until you've tried a refund.

6stages, idea to live
5features at most in your first version
1feature at a time, checked by hand
23guides you can print
£20once, yours to keep

Is this for you?

It's for you if

  • You have an app idea for your business and can't code.
  • You've tried a no-code tool and hit its limits.
  • You want to know first whether a ready-made tool already does the job.
  • You want guard rails: a plan, small steps, tests, and no secret keys left in your code.

It's not for you if

  • You want an app without paying for a coding plan. You'll need Claude Code or Codex.
  • You want someone to build it for you. This is for building it yourself, with the agent.

You'll need

  • A computer.
  • A paid Claude Code or Codex plan, about $20 a month as of November 2026.
  • An evening to set up, then an hour or two a week.

You direct it. The agent writes the code.

Claude Code and Codex can build a real app. What they need is someone who knows what to ask for, reads the plan before saying yes, and keeps the keys out of the chat. That's you, with this folder.

1

Plan it on one page.

Who it's for, the one job it does, and the smallest version: five features or fewer, each with a check.

2

Build it a step at a time.

Setup from zero, a project file the agent reads first, one feature per prompt, the plan read before you say yes, and a save after every working step.

3

Ship it safely.

A database and sign-in, Stripe in test mode first, your own address, and a launch and security checklist before anyone else uses it.

Watch how it works.

Buy, download, open the folder in Claude Code or Codex, and say one sentence. A few minutes, start to finish.

Music: Ovanea by Moavii, from Free To Use.

This is what you get to look at.

Real screens from the folder. The app shown is the worked example that comes with it: an invented barber's booking app, seven weeks in. Every name, date and figure in it is made up, and it says so.

The build dashboard for the invented example app: features shipped week by week, the board, prompts, decisions, bugs, costs and the checklists. On a phone it shows as the phone version: one column, read top to bottom.Swipe sideways to read it all.
Your build on one page: what's shipped, what's next, and what still needs checking.
*** INVENTED EXAMPLE: Fade & Co, its owner, its customers and every date and figure here are made up. ***
Fade & Co Bookings  ·  Wed 21 Apr 2027
Fade & Co Bookings: customers of a two-chair barber's in Leeds book a slot with their barber and pay a £5 deposit.
Features: 6 shipped of 8.  Live at https://fadeandco.example

THE RECORD SAYS
  - The spec says "Card forms of its own: deposits go through Stripe's hosted page", but a Must feature takes payments (f-005). Decide which: move it to Later, or take that line out of 'not doing'.
  - Live, and the backup check isn't ticked. Back up the database and try a restore once.

1. Next to build
   f-007  Text reminder the day before
         check: A test booking for tomorrow gets one text at 6pm today, and only one

2. Bugs open (1)
  b-004  Low     The booking page is slow on an old Android phone

3. Checklist gaps (6)
  stranger        One real person who isn't you has used it without your help, and you w
  terms           Terms, if you take money or people rely on it
  backup          A backup of the database, and you have tried restoring it once
  rollback        You know how to go back to the last version that worked
  few-parts       As few outside packages and services as the job needs
  personal-data   Only the personal data you need; you know where it is stored and who c

4. Shipped in the last 7 days (1)
  2027-04-14  Customers cancel or move a booking up to 24 hours before

Costs: about £35 a month (1 not recorded). Prompts logged: 5.
A working tool, not legal, security or financial advice. If the app holds personal data or takes money, check your obligations with a lawyer or a qualified adviser in your country.
Every morning: what the record says, the next feature, open bugs and checklist gaps.
The guide Reading a plan before you say yes
Reading a plan before you say yes: the guide I'd hand anyone on day one.

Six stages. One at a time.

Already set up? It skips ahead. Starting from a blank laptop? It starts with your first hour.

1

The spec

The problem, one user, the one job the app does, and a list of screens. Cut to the smallest version that works.

2

Setup

The accounts and installs, the terminal and git in plain words, and what it all costs each month.

3

The first build

A project file for the agent, small prompts, the plan read before you say yes, tried by hand, then saved.

4

Data and sign-in

A database, sign-in with a hosted service, and Stripe in test mode until a full purchase and refund work.

5

Ship it

A host, your own address, keys in the host's settings and never in the code, and a launch checklist.

6

Run it

Bugs, costs, people's data, a phone app, and an honest answer to when you need a developer.

Build Your App.

£20 once

The method, the guard rails, a build desk and a worked example, for less than a month of the coding agent.

Instant download · Works, or your money back · Secure checkout with Stripe

Installs nothing · No tracking · Nothing sent to Nine Bar

A folder you keep. Pay with Stripe, download straight away, and we email you the link.

Get it for £20

Or get all six business playbooks, this one included, for £60: Start, Round, Grow, Audience, Save and App. Or any three for £45, your choice.

Already bought it? Get your download link again.

  • The booklet: every guide in one PDF, for your phone or to print
  • The playbook: how to build an app without writing code
  • 23 guides, from your first hour to going live
  • A project file template for Claude Code or Codex
  • The app build plan spreadsheet
  • The build desk, secret scan and dashboard
  • A worked example to learn from

What buyers said.

Word for word.

“Jamie's playbooks are a gamechanger.”

Jay Shah, Sportbuddy

What's in the folder.

The agent reads the playbook. These are yours: 23 guides in my voice, a spreadsheet and a worked example.

The Build Your App folder: the playbook, the tools and a library of guides

Start

Prompts cheat sheetWhat to say to the desk and to the build window, for every stage. Copy, change the words in brackets, and go.
Your first hourFrom opening this folder to seeing your app's first page on your own laptop. One step at a time, with what you should see after each.
Claude Code and CodexWhat a coding agent is, how Claude Code and Codex differ, what they cost, and how to choose. Checked in November 2026: these tools change every month, so check the official pages before you pay.
GlossaryEvery technical word in this pack, in one plain sentence. Look one up whenever the agent uses a word you don't know.

Plan and set up

Should this be an app?Before you build, check whether something already does the job. How to look, what to compare, and the reasons that do and don't justify building your own.
Writing the specHow to turn an idea into one page the coding agent can build from: the person, their problem, the one job, the screens, five features with checks, and what you won't do.
The smallest versionHow to cut your app to the version you can ship in weeks, prove with real people, and build on. Plus the tests to run before you build anything at all.
Installing from zeroEverything to install, in order, on a Mac or Windows laptop, with how to check each one worked. Checked in November 2026: commands change, so if one fails, the official page has the current version.
The terminal in plain wordsWhat the terminal is, the three commands you actually need, and what the scary messages mean. Ten minutes, once.
Git in plain wordsWhat git and GitHub do for you, the five words you'll hear every day, and how to undo a mistake. The safety net under everything you build.
What it costsWhat you'll pay to build and run a small web app, which costs grow quietly, and how to keep the total in view. Checked in November 2026: prices change and vary by country, so log what you actually pay.

Building with the agent

The project fileCLAUDE.md and AGENTS.md: the page the coding agent reads at the start of every session. A template to copy, and why each part is there.
Ten prompts that do most of the workThe ten things you'll say to the build window again and again, written so the agent does the right thing first time. Change the words in brackets.
Reading a plan before you say yesHow to read what the coding agent says it's about to do, the six questions to ask, and the red flags that mean stop. Five minutes that save days.
When it breaksWhat to do when the app stops working or the agent goes in circles: the calm way to find the cause, how to go back, and when to stop and get help.
Adding a databaseWhen your app needs one, how to choose a hosted service, what to tell the agent, and the three checks before real people's details go in.
Sign-inHow to let people sign in without ever storing a password yourself, which kind to choose, and how to check that each person sees only their own things.
The default stack, click by clickOne set of tools that suits most first apps, and every step to set it up: a Next.js web app, Supabase for the database and sign-in, Vercel to host it, Stripe in test mode. Checked against each service's own documentation in November 2026.

Data, money and going live

Taking payments with StripeHow to take money without card details ever touching your app: Payment Links or Checkout, test mode first, and the four-step run-through before a single real payment.
Going liveFrom your laptop to a real address: connecting a host, putting settings in the right place, the preview check, and the launch checklist, item by item.
Keeping secrets secretWhat counts as a secret, where secrets live, how to check none have leaked into your code, and exactly what to do if one does.
People's dataThe plain-English basics of holding personal details in an app: collect less, keep it private, tell people what you do, and know when you need a lawyer. Not legal advice.

Running it

When to hire a developerThe honest list of times a coding agent isn't enough, how to hire for a specific job, and how to keep control of your app when someone else works on it.

Spreadsheets and the worked example

App build planFeatures with their checks, what it costs each month, and the launch and security checklists.
A worked exampleAn invented barber's booking app, seven weeks in: the spec, what shipped when, prompts, decisions, bugs, costs and the dashboard.

The playbook.

How to build without writing code yourself: the order, the habits and the guard rails.

The build desk.

Runs on your computer and never touches the internet or your code: features and their checks, prompts, decisions, bugs, costs, a secret scan and the dashboard.

The rules of the road.

Keys never go in the chat or the code. Test mode before real money. You approve every change to money, data or the live site.

Jamie Mussett Harford
"Not everything needs a £250k app build or a team of ten to get started."

I've started businesses since 2012, and I'm not a developer. Coding agents changed what one person can build. They're fast and confident, and sometimes wrong, so the method matters: one page of spec, one feature at a time, the plan read before you say yes, keys kept out of the chat, and test mode before real money. This folder is that method.

Jamie Mussett Harford

The rules it keeps for you.

A coding agent is fast and confident, and sometimes wrong. So it's careful.

Keys stay secret.

Never in the chat, never in the code. A built-in scan checks your project for anything that looks like a key or password.

You say yes first.

It reads the agent's plan with you before any change to money, people's data, sign-in or the live site.

Test before real money.

Stripe stays in test mode until a full purchase and a refund have worked end to end.

Honest about limits.

It tells you plainly when you need a developer or a lawyer, and it never touches the internet or your code itself.

Questions people ask.

I've never written code. Is this for me?

Yes. That's who it's for. You don't write the code; the coding agent does. You decide what gets built, read its plan before you say yes, and try each step by hand. It explains the terminal and git in plain words, from zero.

What do I need?

A computer, and Claude Code or OpenAI's Codex to build: they need a paid plan with Anthropic or OpenAI. The planning desk (your spec, features, costs and checks) also works in an ordinary Claude chat with nothing to install, or in ChatGPT, Gemini or Copilot. The guide on what it costs lists what to check for your country.

Is it safe to open and run?

Yes. Nothing in the folder installs anything, runs on its own or sends anything to anyone. It holds guides, spreadsheets with no macros, PDFs and one small Python script, app.py, that uses only what comes with Python. It never goes online and has no link to your bank, your email or anyone else. Nothing is ever sent to Nine Bar: no accounts, no tracking. In a chat, what you upload is read by that AI company, so don't upload passwords or card numbers. You can open the script in any text editor and read every line, and the folder includes a page that lists exactly what it does.

Claude Code or Codex?

Either. The folder works with both, and a guide explains how they differ, as of November 2026.

Can I build a phone app?

Start with a web app that works well on a phone. A guide covers when it's worth going further, and the routes to an app in the stores.

Can it take payments?

Yes, with Stripe. It keeps you in test mode until a full purchase and a refund have worked, and your live keys go in your host's settings, never in the code or the chat.

Is this legal or security advice?

No. It's a working method and a set of tools. If your app will hold sensitive data or take significant money, get a developer and a lawyer before you build, and it says so.

Can I get a refund?

If it won't open or run on your computer, yes. Email Jamie within 30 days of buying: we'll help you get it working, and if we can't, we refund you in full. We don't refund a change of mind, because the download is yours the moment you pay.

Before you build, and after.

Build Your App is for when you know what to build.

Start Your Business

£20

Not sure there's a market yet? Find the gap and test it with people who pay before you build anything.

See Start Your Business

Grow Your Business

£20

Once it's live: your offer, a price that leaves a margin, and the customers who come back.

See Grow Your Business

Build Your Audience

£20

So the people who'd use it already know who you are, in your own words.

See Build Your Audience
Build Your App · £20 once Get it