Claude Third-Party Apps: Complete List, How They Work, and Billing Explained
Claude Third-Party Apps: Complete List, How They Work, and Billing
Claude is not limited to claude.ai. Dozens of third-party apps connect to Claude through Anthropic's OAuth system, letting you use Claude's models inside code editors, terminal tools, browser extensions, and automation platforms. This guide covers which apps qualify as third-party, how they connect, what the billing changes mean, and how to keep everything running.
What Counts as a Claude Third-Party App
A Claude third-party app is any tool that accesses Claude's models through your Claude account (via OAuth sign-in) rather than through a direct API key. The distinction matters because Anthropic now bills these two paths differently.
If the app asks you to "Sign in with Claude" or redirects you to claude.ai to authorize access, it is a third-party app. If the app asks you to paste an API key, it uses API billing instead.
Complete List of Claude Third-Party Apps
Here is every major app and tool that connects to Claude as a third-party app, organized by category.
Code Editors and IDEs
| App | What it does | Authentication | Billing pool | |---|---|---|---| | Cursor | AI-powered code editor with Claude models | Claude OAuth | Extra usage | | Windsurf (Codeium) | AI code editor with Claude integration | Claude OAuth | Extra usage | | Claude Code (CLI) | Terminal-based Claude agent for coding | Claude OAuth | Extra usage | | Cline | VS Code extension for Claude conversations | Claude OAuth | Extra usage | | Continue | Open-source AI code assistant | Claude OAuth or API key | Depends on auth method | | Aider | Terminal pair programming with Claude | API key | API billing | | Zed | Code editor with Claude built in | Claude OAuth | Extra usage |
Browser and Productivity Tools
| App | What it does | Authentication | Billing pool | |---|---|---|---| | Claude for Sheets | Use Claude formulas in Google Sheets | API key | API billing | | Raycast Claude Extension | Quick Claude access from macOS launcher | API key | API billing | | MCP-connected tools | Any app using Model Context Protocol | Claude OAuth (through host) | Extra usage |
Automation and Agent Platforms
| App | What it does | Authentication | Billing pool | |---|---|---|---| | Fazm | Desktop AI agent for macOS automation | Claude OAuth | Extra usage | | Zapier Claude Integration | Use Claude in Zapier workflows | API key | API billing | | n8n Claude Nodes | Claude nodes in n8n automation flows | API key | API billing | | LangChain / LlamaIndex | Orchestration frameworks | API key | API billing |
OAuth vs. API key is the deciding factor
Some tools support both connection methods. If you connect with your Claude account (OAuth), usage draws from extra usage credits. If you paste an API key, usage draws from API billing. Check your tool's settings to see which method you are using.
How Third-Party App Authentication Works
When you connect a third-party app to Claude, the app redirects you to claude.ai for authorization. This is standard OAuth: you sign in, grant the app permission, and the app receives a token it uses to make requests on your behalf. You never share your password with the app.
The OAuth flow works like this:
- You open the third-party app and choose "Sign in with Claude"
- The app redirects your browser to claude.ai
- You sign in (if not already) and approve the app's access request
- Claude sends a token back to the app
- The app uses that token for all Claude requests going forward
You can revoke access for any third-party app at claude.ai/settings under the connected applications section.
How Billing Works for Third-Party Apps
Anthropic changed third-party app billing in early 2026. Previously, third-party apps drew from your plan's included usage. Now, third-party app requests draw from a separate prepaid balance called "extra usage credits."
The Three Billing Pools
| Pool | What it covers | How you pay | |---|---|---| | Plan limits | claude.ai web, Claude mobile app | Monthly subscription ($20 Pro, $30/seat Team) | | Extra usage credits | All OAuth third-party apps | Prepaid credits, purchased at claude.ai/settings/usage | | API billing | Apps using API keys | Pay-per-token, billed to your Anthropic API account |
These pools are completely separate. You cannot transfer balance between them.
Starter Credits
When Anthropic made this change, they gave existing accounts a one-time starter credit to ease the transition:
| Plan | Starter credit | |---|---| | Free | $0 | | Pro | $5 to $100 (based on usage history) | | Team | $100 per organization | | Enterprise | $200 per organization |
What Happens When Credits Run Out
Once your extra usage balance reaches zero, all third-party apps stop working. You will see messages like "LLM request rejected" or "you're out of extra usage." Your claude.ai and mobile app access is unaffected.
To keep going, add more credits at claude.ai/settings/usage. You can configure auto-reload to refill your balance automatically when it drops below a threshold.
Managing Usage Across Multiple Third-Party Apps
If you use several third-party apps (say Cursor for coding and Claude Code for terminal tasks), they all draw from the same extra usage credit pool. There is no way to allocate credits per app.
Tips for managing usage across apps:
- Check your balance regularly at claude.ai/settings/usage
- Set up auto-reload so you never run out mid-session
- Use Sonnet for routine tasks instead of Opus, since Opus costs significantly more per request
- Close apps you are not actively using to avoid background requests that drain credits
- Review connected apps in your Claude settings and revoke access for tools you no longer use
Troubleshooting Common Issues
"LLM Request Rejected" After the Billing Change
This means your extra usage credits are at zero. Go to claude.ai/settings/usage and add credits or claim your starter credit if you have not already.
Third-Party App Cannot Connect
Check that you are signing in with the correct Claude account. If you have multiple accounts (personal and work), the app connects to whichever account you authenticate with. The extra usage balance is tied to that specific account.
Organization Account Shows Rejection for All Team Members
On Team and Enterprise plans, a workspace administrator must claim the starter credit before team members can use it. Ask your admin to visit claude.ai/settings/usage and accept the organization credit.
App Works With API Key but Not OAuth
Some apps support both authentication methods. If OAuth is not working (credits exhausted), switching to an API key is an option, but it bills differently. API billing is pay-per-token and does not use your extra usage balance.
Which Connection Method Should You Use
If your tool supports both OAuth and API keys, here is how to choose:
| Factor | OAuth (extra usage) | API key (API billing) | |---|---|---| | Setup complexity | Simple, just sign in | Need to generate and manage keys | | Billing | Prepaid credits, fixed cost | Pay-per-token, variable cost | | Rate limits | Tied to your plan tier | Tied to your API tier | | Best for | Individual developers, small teams | Production apps, high-volume usage | | Cost control | Buy credits in advance | Set spending limits on API account |
For most individual developers using Cursor or Claude Code, OAuth is simpler and the prepaid credit model makes costs predictable. For production applications or high-volume automated workflows, API keys give you more granular control over spending and rate limits.