Use ChatGPT or Claude as a thinking partner before you build: ask it to interview you about your idea one question at a time, then summarize it into a one-page plan covering users, each user's journey, first-version features and what to postpone, data and rules, payments and notifications, and risks. Then ask it to turn the plan into a build prompt and paste that into a builder like Fanann. Plan in the chat; build in the builder.
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Why plan your app with ChatGPT or Claude before building it?
Planning with ChatGPT or Claude before you build means using a chat assistant as a thinking partner that turns the scattered idea in your head into a clear one-page plan, then into a ready build prompt. Chat assistants are good at asking questions, organizing ideas and spotting what you forgot. A builder like Fanann turns the plan into a working app: it builds the interface, logic and database, tests, and publishes.
Why not just start building? You can, and many people succeed. But when the idea is incomplete, you discover missing decisions mid-build: who can cancel an order? What happens to the deposit? Can a customer have more than one address? Each late decision means another edit and sometimes rebuilding a part. An hour of planning settles most of these upfront.
- Questions you, discusses and organizes ideas
- Writes the plan and feature descriptions
- Suggests questions for potential customers
- Turns the plan into a build prompt
- Builds the interface, logic and database
- Connects local payments and phone sign-in
- Tests pages and fixes bugs
- Publishes on in-region hosting and ships the mobile app
What should you come out of the planning chat with?
The goal is not to read nice ideas but to leave with a short document you could hand to any person, or any tool, and have them understand what you want. Its elements:
| Element | The question | Short example (mobile car wash) |
|---|---|---|
| Problem | What frustrates customers today? | No time to drive to a car wash; long waits |
| Users | Who uses the app? | Customer, washer, manager |
| Core journey | What are the steps end to end? | Set location, pick a package, book, pay, rate |
| First version | What is the minimum that solves the problem? | Booking, payment and the washer's schedule; no subscriptions |
| Later | What is not needed now? | Monthly subscriptions, loyalty points, a separate washer app |
| Data and rules | What is stored, under what conditions? | Customer cars, appointments, served areas |
| Payments and alerts | How do customers pay, and when are they notified? | mada and Apple Pay; WhatsApp confirmation and reminder |
| Risks | What could go wrong? | Orders in unserved areas, late cancellations, weather |
The planning conversation in 6 steps
- 1Ask it to interview you
Start with: 'I have an app idea. Do not suggest solutions yet. Ask me one question at a time to understand the problem, customers and market, and after 10 questions summarize what you understood.' This stops it jumping to a generic app.
- 2Define users and journeys
'Write each user type's journey step by step, and flag any step that is unclear or needs a decision from me.'
- 3Cut to the first version
'Split features into: essential for version one, useful later, unnecessary. Be strict; I want the smallest version that solves the problem.'
- 4Describe data and rules
'What does the app store and how do those things relate? Which rules must I decide: cancellation, deposits, permissions?'
- 5Ask for critique
'Act as a skeptical investor and an impatient customer. What is the weakest point of this idea, and what might stop a customer from finishing an order?'
- 6Write the build prompt
'Turn the plan into a build prompt for an AI app builder: users, journeys, data, rules, payments, notifications and look. State what is not in version one.'
You can do this in one session. If the chat gets very long, ask for an updated summary from time to time; models have a limited context window and can lose precision on details mentioned early in a very long conversation.
From plan to a Fanann build prompt
Here is a build prompt that came out of a planning chat for a mobile car wash. Notice it carries decisions settled in the conversation, not general ideas.
Build a booking app for a mobile car wash in Riyadh, interface in Arabic RTL with an English option. Users: customer, washer, manager. Customer: signs up with phone number (OTP), adds cars (type, size, color, plate number), pins their location on a map, picks a package (exterior, interior and exterior, polish) priced by car size, books an available slot, and pays with mada or Apple Pay. Rates the service afterwards. Washer: sees today's jobs in order with locations, and updates status: on the way, started, finished, with a photo after the wash. Manager: adds packages, prices, washers and served districts, and sees bookings and revenue. Rules: no bookings outside served districts. One booking per washer at a time, with 30 minutes travel between jobs. Free cancellation up to 3 hours before; 50% charged after that. Notifications: confirmation and a one-hour reminder on WhatsApp, plus an alert when the washer sets off. Not in version one: monthly subscriptions, loyalty points, a separate washer app. Look: blue and white, clean, mobile-first.
Try it in FanannChatGPT or Claude for planning?
Both can handle this kind of planning in Arabic and English, and the differences shift with every new version. The practical rule: use the one you know and have access to. For a second opinion, give the same plan to the other and ask it to critique it. Disagreement between two models sometimes reveals points you missed.
- If you have long documents (market research, meeting notes), pick the tool that handles long files comfortably on your current plan.
- Judge by results, not reputation: which assistant asked smarter questions about your business?
- Do not move the whole chat between tools; move only the condensed plan.
For a wider comparison of the two for planning and building, read ChatGPT vs Claude for planning and building apps.
Mistakes that make AI planning a waste of time
- The assistant agrees with everything: models lean encouraging. Ask for critique explicitly, and for the worst-case scenario.
- Market numbers from memory: if the assistant quotes a market size or adoption rate, do not base decisions on it without a reliable source you check yourself.
- Endless planning: there is no perfect plan. After an hour or two, build a first version and show it to real customers.
- A plan that ignores the local market: remind it of the context: mada and Apple Pay, WhatsApp, Hijri dates, the National Address, a Friday–Saturday weekend in Saudi Arabia.
- A huge first version: if version one has more than 5 to 7 core features, it probably needs cutting.
After the plan: validate, build, then learn
The plan is not the goal. Your next step is to test the idea with real people as fast as possible. Sometimes a landing page with a sign-up form is enough to gauge interest; sometimes you need a working first version.
- Ask the assistant for 10 questions to put to potential customers, and talk to at least 5 of them.
- Update the plan based on what you heard, not what you hoped.
- Build version one in Fanann with the build prompt, then add one feature per message.
- Show it to the same customers and watch where they get stuck.
For a full week from idea to first version, read from idea to MVP in 7 days, and for ways to test demand see validate your app idea.
Key takeaways
- A chat assistant is great for thinking and organizing; the builder is what builds, tests and publishes.
- Ask the assistant to question you first instead of proposing a generic app.
- The output you want: a one-page plan, then a build prompt derived from it.
- Ask for blunt critique, and never trust market numbers or legal facts without checking.
- Do not over-plan: one to two hours is usually enough for a first version.
Frequently asked questions
How do I use ChatGPT to plan an app?
Can ChatGPT or Claude build the app itself?
Which is better for planning: ChatGPT or Claude?
How long should planning take before building?
Should I trust market numbers the assistant gives me?
Ask your AI assistant about this
Copy this prompt into the AI assistant you use, then add the details of your own case.
I am reading this guide: “Use ChatGPT or Claude to plan your app before you build it” https://fanann.com/en/blog/plan-app-with-chatgpt-claude/ My question: how to use chatgpt to plan an app Use that page as a source and explain the answer step by step for my situation, tell me what to check before I start, and cite the page link.