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Building Apps with AI

There’s a meaningful difference between using AI and building with it.

Using AI means you’re in the loop for every task — you type a prompt, you get a response, you decide what to do with it. That’s genuinely useful, and this site covers it extensively.

Building with AI means your code is in the loop. Your program sends the prompt, receives the response, and acts on it — without you sitting there. This is what lets AI work at scale, run on a schedule, integrate with your other tools, and become a feature in something you ship to others.

If you can write a few lines of code, or you’re willing to learn, you’re a lot closer to this than you might think.


Once you can call the API directly, a wide range of things open up.

What You Can BuildExample
ChatbotsA customer support bot that knows your product’s documentation
Internal toolsA Slack bot that summarizes meeting notes and sends them to the right channel
Automation scriptsA script that reads your inbox every morning and drafts replies to the important ones
Data pipelinesA system that ingests raw survey responses and extracts structured sentiment
Personal assistantsAn agent that manages your calendar, drafts emails, and tracks your tasks
Document processingA tool that reads contracts and flags non-standard clauses
Code reviewersA pipeline that reviews every pull request before it reaches your team

The common thread: you define the workflow once, and it runs without you.


Path 1: Use the API directly. You write code that calls the Anthropic API. You’re in full control — of the prompt, the model, the output format, what happens with the response. Start here if you’re building something that needs to be deployed, shared, or run at scale.

Path 2: Use Claude Code to build things for you. Claude Code can write, test, and iterate on code while you describe what you want. You describe the tool, Claude builds it, you use it. This is how the site you’re reading was built. Start here if you want to build something for personal use and you’re more comfortable describing than coding.

In practice, these paths meet in the middle. Claude Code is excellent at writing the API integration code that Path 1 requires.


PageWhat You’ll Learn
Your First API CallHow the API works, getting your key, working code examples in Python and JavaScript
Putting It All TogetherHow to chain multiple AI calls into powerful automated workflows — with real case studies

Start with Your First API Call if you haven’t made an API call before. It covers everything from getting credentials to working code. Then read Putting It All Together to see how individual API calls combine into systems that do things no single prompt can.