Which Claude Should I Use?
"Claude" comes in a few flavors. Pick by what you're trying to do, not by which you've heard of.
- Match your goal to the right Claude surface: chat, Claude Code, or the API
- Know when mobile and voice fit into the picture
- Understand how the three surfaces work together as you level up
- Get a quick read on which model to reach for once you start building
The 30-second decision
The three surfaces at a glance
| Surface | Best for | Who | Start here |
|---|---|---|---|
| Claude.ai | Writing, research, analysis, learning, planning, everyday questions | Everyone, no setup | Getting Started with Claude.ai |
| Claude Code | Working in a codebase — reading, editing, running commands, fixing tests | Developers (and the technically curious) | What Claude Code Is |
| API & Agent SDK | Apps, automations, and agents that call Claude programmatically | Developers shipping a product or pipeline | Your First API Call |
Claude.ai — the chat apps
Claude.ai is the no-setup starting point for everyone. You also get it on mobile (iOS/Android) and by voice — great for capturing ideas on the go. Power it up with Projects, custom instructions, and Artifacts.
Claude Code — the agentic coding tool
Claude Code works inside your project. It reads, edits, runs commands, and fixes tests — acting on your files with your permission.
The API & Agent SDK — build Claude into your own software
The API and Agent SDK let your own software call Claude programmatically, so you can ship AI features, automations, and agents.
They work together
These aren't rival products — most people graduate across them:
| You want to… | Use |
|---|---|
| Draft an email, summarize a PDF, brainstorm | Claude.ai (or voice/mobile) |
| Refactor a module, add tests, fix a bug | Claude Code |
| Add an AI feature to your app | The API / Agent SDK |
:::tip Not sure? Start with chat Claude.ai needs zero setup and teaches you how Claude "thinks." The skills transfer everywhere else. :::
Which model, once you're building?
Picking a surface is step one. When you move to Claude Code or the API, you also pick a model — Haiku, Sonnet, or Opus. Answer three quick questions and this picker suggests a starting point:
The balanced default — strong reasoning and coding at a fraction of Opus cost. Start here, and only move up if you hit a real quality ceiling.
Look up the exact model ID on the models table. Rule of thumb only — run a quick eval on your own inputs to be sure.
:::note Don't hard-code the names Model lineups and prices change. Always confirm the current model IDs on the Choosing a Claude Model page before you ship. :::
Check yourself
Check yourself
0/3- Claude.ai: zero-setup chat for writing, research, and everyday work — also on mobile and by voice
- Claude Code: an agent that acts inside your codebase
- API & Agent SDK: build Claude into your own software
- They compose — most people start with chat and graduate to Code and the API
- Pick a model (Haiku / Sonnet / Opus) only once you're building, and verify current IDs before shipping
Next
- Your First 5 Minutes
- Learning Paths
- Choosing a Claude Model (once you're building)