Docs

Quickstart

Three steps. Your code stays the same.

1. Connect OpenRouter

Sign up and approve the OpenRouter connection. OpenRouter creates a key for us on your account. You buy credits there, not here. Then create an fmc_ key on the OpenRouter page of your dashboard.

2. Swap the base URL

Python

from openai import OpenAI client = OpenAI( base_url="https://api.fakemodelcheck.com/v1", api_key=FMC_KEY, ) r = client.chat.completions.create( model="deepseek-v4-1-flash", messages=[{"role": "user", "content": "Hello"}], ) print(r.receipt)

TypeScript

import OpenAI from "openai"; const client = new OpenAI({ baseURL: "https://api.fakemodelcheck.com/v1", apiKey: process.env.FMC_KEY, });

3. Read the receipt

Every response carries a receipt with the provider that served it and its last check. See Receipts.

Models

Use our name or the OpenRouter name. Any other model passes through unchanged and is marked unchecked.

  • deepseek-v4-1-flash or deepseek/deepseek-v4.1-flash-1017 DeepSeek V4.1 Flash
  • glm-5-3 or z-ai/glm-5.3 GLM 5.3
  • kimi-k3 or moonshotai/kimi-k3 Kimi K3

Without an account

You can also send your own OpenRouter key as the bearer token. We use it for that one call, never store it, and keep no log.

Routing mode

Send the header x-fmc-mode: balanced to also allow providers we are still watching. The default is strict.