How to Build an App With Claude: No-Code to Vibe Coding
A step-by-step guide to building a real app with Claude — from idea to working product. No coding experience needed. Covers spec writing, building, and deploying.
In 2024, building an app meant hiring a developer or spending years learning to code. In 2026, it means having a clear idea and a conversation with Claude. This guide shows you exactly how.
What We're Going to Build
Throughout this guide we will use a concrete example: a client invoice generator — a tool where you enter a client name, project description, hours worked, and hourly rate, and it generates a formatted invoice you can download as PDF. This is a real tool a freelancer or small business owner would actually use.
The same process works for any tool: a booking form, a price calculator, a stock checker, an internal dashboard. The steps are identical.
Step 1: Write a Clear Spec
The biggest mistake people make is jumping straight into Claude and saying "build me an app". Claude will build something — but it probably won't be what you wanted, because you haven't told it enough.
Before you write a single prompt, write a spec. A spec is a plain-English description of:
- →What the tool does (one sentence)
- →Who uses it and when
- →What they input
- →What they get out
- →Any important constraints (design, technology, integrations)
Example spec:
Tool: Client invoice generator
User: Freelancer or small agency owner
Input: Client name, project title, line items (description + hours + rate), payment due date
Output: A formatted invoice page with totals, downloadable as PDF
Constraints: Simple HTML/CSS only, no database, works in browser, professional look
This spec takes 5 minutes to write. It will save you hours of back-and-forth later.
Step 2: Write the Build Prompt
Now take your spec and turn it into a prompt for Claude. The key principles:
- →Give Claude the whole spec upfront — don't feed it one requirement at a time
- →Specify the technology stack if you have a preference (HTML/CSS/JS, React, Python, etc.)
- →Ask for working code, not explanations — 'write the full code' not 'explain how to build this'
- →Specify the output format — 'put everything in one HTML file I can open in a browser'
Example build prompt:
>
Build me a client invoice generator as a single self-contained HTML file I can open in a browser.
The user enters: client name, project title, up to 10 line items (description, quantity, unit price), and a payment due date.
The app calculates totals with VAT at 20%. The output is a formatted invoice that looks professional.
Add a "Download as PDF" button that uses the browser print dialog.
Use only HTML, CSS, and vanilla JavaScript. No frameworks. No external dependencies.
Step 3: Review and Iterate
Claude will generate a first version. It probably won't be perfect. That's expected and fine. Your job now is to review and refine:
Paste the code into a browser and see if it runs. Most first versions from Claude work. If it doesn't, paste the error message back to Claude and ask it to fix it.
Test the functionality. Does it do what you specified? Note what's missing or wrong. Be specific: 'The total doesn't include VAT' not 'the numbers are wrong'.
Refine the design if needed. 'Make the header darker', 'increase the font size', 'add my company name at the top'. Claude handles CSS changes fluently.
Add any features you forgot in the spec. 'Also add a notes field at the bottom', 'add a logo placeholder'.
Most tools are done in 3–5 rounds. The iteration speed is what makes this workflow powerful — each loop takes minutes, not days.
Step 4: Deploy It
A tool that lives on your hard drive is a tool only you can use. Deploying it means anyone can access it via a URL. Here are the main options:
Drag your HTML file onto netlify.com/drop. Instantly live at a random URL. Free. Perfect for testing.
Paste your code into Replit, hit Deploy. Free tier available. Gets a real URL.
Push to a GitHub repo, enable Pages. Free. Good for tools you want to keep long-term.
Build and deploy in one place. Paste your spec into Bolt and it handles both building and hosting.
The Bigger Picture: What You Can Build
The invoice generator is just an example. Here is what real small business owners and freelancers have built using exactly this process:
When to Ask for Help
The biggest drop-off point is when something breaks and you don't know why. Most errors have simple fixes — but only if you know how to read an error message and describe it to Claude.
A one-day workshop teaches you exactly this: not just how to prompt Claude, but how to diagnose when it goes wrong, how to break complex builds into smaller pieces, and how to go from prototype to something polished enough to share.
$ tools --recommended
Start with the right tools
The AI used in the Build With Claude workshop. Best for building and code generation.
OpenAI's flagship. Strong for research, image generation, and browsing.
AI built into your workspace. Useful for specs, planning, and docs.
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Frequently Asked Questions
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Build With Claude is a one-day hands-on workshop where you arrive with an idea and leave with a working tool. 8 seats. Richmond, SW London. Expert in the room all day.
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