How to Build an App with Claude

Artifacts

Build small interactive apps right in a Claude chat and preview them instantly. Best for tools, calculators, and prototypes.

Claude Design

Turn a prompt into interactive prototypes and mockups, then pass them to Claude Code.

Claude Code

Build a real app in a project folder on your computer or in the cloud. Comes with every paid plan.

Prototype in chat. Build the real thing in Claude Code.

• Who will use the app?
• Which problem does it solve?
• How do people handle it today?
• What is the single most important action?
• How will you know the app works?

An app that solves one problem well beats one that solves ten problems badly.

Ask Claude to help you draft a one-page spec covering:

• Users and their goals
• Core features in version one
• Features to save for later
• Screens and what each one shows
• Data the app stores
• Sign-in needs
• What stays out of scope

Interview me about this app idea, one question at a time. Then write a one-page spec with a tight version one scope.

Use artifacts or Claude Design to click through the main flow before you build anything.

• Test the main screens
• Confirm the key action takes only a few steps
• Show it to two or three real users
• Update the spec based on their feedback

Changes cost the least before any real code exists.

Ask Claude to recommend a stack that fits your skill level and app type, and to explain its choice.

Web app

A popular framework with solid documentation

Mobile app

A cross-platform framework, if you need both iOS and Android

Data

A hosted database with built-in sign-in, if users need accounts

Hosting

A platform that deploys straight from your Git repository

Pick popular, well-documented tools. Claude knows them better, and help is easier to find.

curl -fsSL https://claude.ai/install.sh | bash

Make a project folder, run claude inside it, and switch to Opus 5.5 for complex work:

/model opus /effort high

Rather skip the terminal? The Claude desktop app has Claude Code in its Code tab.

Run /init to generate a CLAUDE.md file, then add:

• What the app does
• Which tech stack it uses
• How to run, test, and build it
• Which code style rules apply
• What Claude must ask about first

Claude reads this file at the start of every session.

Ship one feature at a time:

• Ask Claude for a plan first
• Approve the plan
• Let Claude build that feature
• Run the app and test it yourself
• Commit to Git once it works
• Move on to the next feature

Small, tested steps always beat one giant prompt.

Have Claude set up Git and commit after every working step. If something breaks, you can always roll back to the last good version.

• Store only the data you truly need
• Use a proven sign-in service rather than building your own
• Keep secrets in environment variables, never in the code
• Set database access rules so each user sees only their own data
• Back up any important data

• Have Claude write automated tests for the core features
• Run the tests after every single change
• Click through the whole app yourself
• Test it on a phone
• Enter wrong inputs on purpose
• Have a friend use it with no help

When something breaks, tell Claude:

• What you did
• What you expected to happen
• What actually happened
• The exact error message
• A screenshot, if the bug is visual

Have Claude find the root cause before it changes any code.

Claude Code ships with a built-in security check. Run it before every deploy:

/security-review

It scans the changes on your branch for risks such as injection, sign-in and access flaws, and data exposure. It compares your branch with the main branch of your remote repository, so push the project to GitHub (or another Git host) first.

Then have Claude fix what it found:

Fix these security issues one by one, starting with the most severe. Explain each fix, and wait for my approval before moving to the next.

If your app handles payments, health, or sensitive personal data, get a human expert to review it as well.

• Pick a hosting platform
• Set environment variables on the platform, not in code
• Connect your domain
• Test the live version
• Set up error monitoring

Have Claude guide you through each step on the platform you chose.

• Gather feedback
• Note where people get stuck
• Fix the biggest problem first
• Add features only when users need them

Problem

Define one clear problem.

Spec

Scope version one.

Prototype

Click through it before you build.

Build

Ship one feature at a time.

Test

Run automated checks and test by hand.

Secure

Review security before launch.

Ship

Deploy and monitor.

Improve

Learn from real users.

Act as my senior developer and teacher. I want to build [app] for [users] to solve [problem]. First, interview me and write a one-page spec with a small version one. Wait for my approval. Then suggest a simple, well-documented stack and explain your choice. Build one feature at a time: plan it, build it, write tests, run them, and explain what you did in plain language. Commit after every working step. Never put secrets in code, and ask me before you delete anything or deploy.