Big Picture 1: Where a Request Comes From
Claude is one model family with several entry points. Whichever one you use, the same thing happens underneath: a Messages API request is built and sent to the same model. This stage is the map of those entry points.
- 1.You ask Claude a question on some surface
- 2.Surface: claude.ai apps, Claude Code, Claude API + SDKs, Agent SDK, Managed Agents or Cloud
- 3.The surface builds a Messages API request
- 4.The same model family answers it
- 5.Next stage: what is inside this request
Every surface ends in the same kind of request.
The entry points, one by one
- claude.ai / Desktop / Mobile: the most familiar entry point. You chat, create Projects, see Artifacts, run Research and can even talk by voice.
- Claude Code: built for developers. It runs as a CLI, inside VS Code and JetBrains, on the web, and in Slack and GitHub Actions. Claude works directly on your code.
- Claude API + SDKs: your program sends a POST request to /v1/messages. SDKs exist for Python, C#, TypeScript, Java, Go and more, so you do not write raw HTTP.
- Agent SDK: the same loop that powers Claude Code, running inside your own app.
- Managed Agents: Anthropic hosts both the agent loop and the sandbox for you.
- Cloud: if your company already lives on a cloud, Claude is available on Bedrock, Vertex AI and Foundry. Same model family, the entry point just belongs to your cloud.
- Messages API request: the one thing every surface builds internally. Chat app or Claude Code, the same kind of request goes out and the same model answers it.