Use Anthropic SDK with llmapi.cheap
Run Anthropic SDK on Gemini 3.8 Flash, Claude Sonnet 4.6, Claude Opus 4.6 or GPT-OSS with a single llmapi.cheap key. Plans start at $2 a month, and there is a free one-hour trial.
Setup
TypeScript:
import Anthropic from "@anthropic-ai/sdk"
const client = new Anthropic({ baseURL: "https://llmapi.cheap", apiKey: "YOUR_API_KEY" })
const msg = await client.messages.create({
model: "claude-sonnet-4-6",
max_tokens: 1024,
messages: [{ role: "user", content: "Hello" }],
})Endpoints
Use the base URL that matches the protocol your tool speaks.
- OpenAI
- https://llmapi.cheap/v1
- Anthropic
- https://llmapi.cheap
- Gemini
- https://llmapi.cheap/v1beta
- Models
- https://llmapi.cheap/v1/models
Model IDs
Any of these work wherever Anthropic SDK asks for a model name. Gemini 3.8 Flash (high) is the default the setup command picks.
| Model ID | Model |
|---|---|
gemini-3.8-flash-high | Gemini 3.8 Flash, high reasoning (default) |
gemini-3.8-flash | Gemini 3.8 Flash, medium reasoning |
gemini-3.8-flash-low | Gemini 3.8 Flash, low reasoning |
gemini-3.1-pro-high | Gemini 3.1 Pro, high reasoning |
gemini-3.1-pro-low | Gemini 3.1 Pro, low reasoning |
gemini-3-flash | Gemini 3 Flash |
claude-sonnet-4-6 | Claude Sonnet 4.6 |
claude-opus-4-6 | Claude Opus 4.6 |
gpt-oss-120b | GPT-OSS 120B |
Troubleshooting
- 401 / invalid key: check the key starts with
sk-llm-and has no extra spaces. Create a new one under Dashboard → API keys if needed. - Model not allowed: the free trial covers the Gemini models; Claude and GPT-OSS come with any paid plan.
- 404 on requests: OpenAI-style tools need
https://llmapi.cheap/v1; Anthropic-style tools needhttps://llmapi.cheapwithout/v1.
