Short answer
A Claude Code relay is an Anthropic-compatible endpoint. Point ANTHROPIC_BASE_URL at it and put the relay's key in ANTHROPIC_AUTH_TOKEN: the relay then authenticates and bills Claude Code's requests and forwards them to the Anthropic model you chose. OpusVIP needs no Anthropic account, and you pay 15% of list price.
What a Claude Code relay is
By default, Claude Code sends requests to Anthropic's API. It can also send them to any Anthropic-compatible address set in ANTHROPIC_BASE_URL; Anthropic's documentation calls this kind of service an LLM gateway. A relay is such an address. It receives Claude Code's requests, handles authentication, billing and logging, forwards each request to the Anthropic model you chose, and returns the response unchanged.
With OpusVIP, a request travels from Claude Code in your terminal or IDE to api.opusvip.dev, which authenticates it, bills it at list price and logs it. From there it goes to the model you picked: Opus 5.5, Fable 5.1, Sonnet 5.5 or Haiku 5.5. For Claude Code, only the address and the key change. Everything else works the same.
How a relay differs from going direct
| Item | Anthropic direct | OpusVIP relay |
|---|---|---|
| Account | An Anthropic account (subscription or API) | An OpusVIP console account; Google sign-in supported |
| Payment | USD, with a card Anthropic accepts | USD via Stripe: card, Alipay or WeChat Pay |
| Price | List price | List prices converted to credits; you pay 15% of list price |
| Setup | Sign in to Anthropic or set an official API key | Set two environment variables, ANTHROPIC_BASE_URL and ANTHROPIC_AUTH_TOKEN |
| Usage detail | The official console | A console log line per request: model, each token type, credits charged |
With OpusVIP you top up with a card, Alipay or WeChat Pay, need no Anthropic account, set up with two environment variables, and see every request logged in the console. For what to check before picking a relay, see How to choose a Claude Code relay.
Set up Claude Code with a relay
- Install Claude Code. Install it globally with npm (Anthropic asks for Node.js 22 or later). If downloads from the npm registry are slow, you can use the npmmirror registry (
--registry=https://registry.npmmirror.com). - Sign up and top up. Sign up to the OpusVIP console (Google sign-in supported) and top up by card, Alipay or WeChat Pay, from $1.50.
- Create a key. On the token page, create an API key starting with
sk-. - Set two environment variables and verify. Run the commands below. A reply means you are connected. For Windows and a permanent setup, see the Claude Code setup docs.
npm install -g @anthropic-ai/claude-code
claude --versionexport ANTHROPIC_BASE_URL=https://api.opusvip.dev
export ANTHROPIC_AUTH_TOKEN=sk-your-key
claude -p "hello"With ANTHROPIC_AUTH_TOKEN set, Claude Code uses that key directly, with no Anthropic sign-in. The default model is Opus 5.5; type /model in a session to switch, as described in Choosing and switching models.
Network and proxies
If you run proxy software or set variables such as HTTPS_PROXY, HTTP_PROXY or ALL_PROXY, make sure they do not block or misroute api.opusvip.dev. For connection timeouts, TLS errors, 401 or 404, work through the troubleshooting checklist.
What it costs
OpusVIP bills at Anthropic's list prices, and you pay 15% of them: 1 credit is $0.01 of usage at list price, and 100 credits cost $0.15. For Opus 5.5 that is $0.60 per 1M input tokens and $3 per 1M output tokens. Context that Claude Code resends in a long session is billed at cache rates, and failed requests are free. Full prices are on Models and pricing; for how caching lowers the bill, see Cache hit rate and billing explained.
Questions? Email hello@opusvip.dev.