SubscriptionsClaude Access
Claude Access
API Key Product
Get access to Anthropic's Claude models including Claude Sonnet 4, Claude Opus 4.5 and more. Use them in any OpenAI-compatible chat client or application. Each subscription includes one dedicated API key.
What's included
- Claude Sonnet 4 & Opus 4.5
- Single dedicated API key
- Priority setup
- WhatsApp support
How to use your Claude API key
1
Get your API key
After purchase, we'll send your dedicated API key via WhatsApp. You'll also find it in your account dashboard under API Keys.
2
Install Chatbox on any device
Download **Chatbox** — a free app for all platforms:
- **Windows**: Download for Windows
- **macOS**: Download for Mac
- **Linux**: Download for Linux
- **Android**: Get it on Google Play
- **iOS**: Get it on the App Store
- **Browser**: Use the web version directly — no install needed
It works seamlessly with custom OpenAI-compatible APIs.
- **Windows**: Download for Windows
- **macOS**: Download for Mac
- **Linux**: Download for Linux
- **Android**: Get it on Google Play
- **iOS**: Get it on the App Store
- **Browser**: Use the web version directly — no install needed
It works seamlessly with custom OpenAI-compatible APIs.
3
Configure for Claude
Open Chatbox → Settings → **AI Provider** → **OpenAI API Compatible**. Set:
- **API Key**: Your Claude key
- **API Domain**: `https://api.virtusub.xyz/v1`
Click **Save**.
- **API Key**: Your Claude key
- **API Domain**: `https://api.virtusub.xyz/v1`
Click **Save**.
4
Select a Claude model
In the model selector, choose from: **claude-sonnet-4-20250514**, **claude-opus-4-20250514**, **claude-sonnet-4.6**, etc. Sonnet is great for everyday use; Opus is best for complex reasoning.
5
Optional: Use with Claude Code CLI
Your key also works with Claude Code — the official CLI tool. Run: `export ANTHROPIC_BASE_URL=https://api.virtusub.xyz/v1` and authenticate with your API key.
Pro tip
All our AI models use a single compatible API format. If you can configure one, you can configure them all. The base URL https://api.virtusub.xyz/v1 works for every AI model key.
Frequently asked questions
Can I use this with Cursor?
Yes. In Cursor → Settings → Models, choose OpenAI-compatible and set the endpoint to `https://api.virtusub.xyz/v1`.
Is there a token limit?
Claude models have large context windows (200K tokens). Your usage is tracked in the dashboard.