Build your first app with Claude Code: a step-by-step guide for first-time builders in the AI Builder Challenge 2026, from setup in the Claude desktop app to a tested AI app at a public link on Render.
A step-by-step guide for first-time builders in the AI Builder Challenge 2026: set up Claude Code, build a small AI app in safe steps, get a model API key, test it and publish it at a public link.
Build your first app with Claude Code: a step-by-step guide for AI Builder Challenge 2026 participants who have never built an app. Claude Code comes with paid Claude plans (Pro, Max, Team and Enterprise). The Claude desktop app includes it, so no terminal is needed: open the Code tab, choose Local and select an empty project folder.
Plan before you build: in Plan mode, paste a starter prompt with the brief and six practice facts for the fictional note-taking app Zephnote, read the plan, then build in Manual mode in four small steps (the page, the server endpoint, the real AI call, friendly errors and limits), committing after each working step.
Connect the AI with a separate model API key: the Gemini API free tier in Google AI Studio or prepaid Claude API credits, stored as MODEL_API_KEY in a .env file that is never committed, pasted into the chat or shown in the page. A Claude plan pays for Claude Code, not for the AI inside your app.
Test with six tests in the desktop preview, then publish: put the code on GitHub with GitHub Desktop, run it as a Render web service with the key as an environment variable, and retest the public address in a private window. Free Render services sleep after 15 minutes without visitors. The guide ends with a recovery table for common problems, a safety checklist and curated official and community resources.