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Welcome to CheckThat AI API

CheckThat AI provides a unified LLM access platform that connects you to 11+ models from leading AI providers through a single API. Built with integrated fact-checking and claim normalization capabilities, it’s the perfect solution for applications requiring both AI power and truth verification.

CheckThat AI Platform

Visit the main platform to get started

Python SDK

Install our Python SDK for easy integration

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Base URL

All API requests should be made to the following base URL: 
https://api.checkthat-ai.com/v1

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Platform Features

Unified LLM Access

Access 11+ models from OpenAI, Anthropic, Google Gemini, xAI, and Together AI through one API

Fact-Checking Built-in

Every response includes built-in claim verification and evidence sourcing

OpenAI Compatible

Drop-in replacement for OpenAI SDK - no code changes required

Multiple Providers

Switch between providers seamlessly: OpenAI, Anthropic, Google, xAI, Together AI

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Supported Providers & Models

  • OpenAI
  • Anthropic
  • Google
  • xAI
  • Together AI
Latest Models:
  • GPT-5
  • GPT-5 nano
  • o3
  • o4-mini
  • GPT-4o

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Authentication

CheckThat AI uses your existing provider API keys. You need API keys from the providers whose models you want to use (OpenAI, Anthropic, Google, etc.).
Authentication is handled using your provider-specific API keys:
  • Environment Variables
  • Python SDK
  • Direct API Calls
Set your provider API keys as environment variables:
export OPENAI_API_KEY="your-openai-key"
export ANTHROPIC_API_KEY="your-anthropic-key"  
export GEMINI_API_KEY="your-gemini-key"
export XAI_API_KEY="your-xai-key"
export TOGETHER_API_KEY="your-together-key"
You only need API keys for the providers whose models you plan to use. Get API keys directly from: OpenAI, Anthropic, Google AI, xAI, Together AI.

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Rate Limiting

The API implements rate limiting to ensure fair usage across all users. Rate limits are applied per API key and vary based on your subscription plan.
Monitor the response headers for rate limit information:
  • X-RateLimit-Limit: Maximum requests per time window
  • X-RateLimit-Remaining: Remaining requests in current window
  • X-RateLimit-Reset: Time when the rate limit window resets

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Getting Started

1

Install the Python SDK

Install CheckThat AI Python SDK via pip:
pip install checkthat-ai
The SDK is compatible with Python 3.8+ and provides full type hints.
2

Get provider API keys

Obtain API keys from the providers you want to use:
3

Make your first request

Use CheckThat AI exactly like the OpenAI SDK:
from checkthat_ai import CheckThatAI

client = CheckThatAI(api_key="your-openai-key")

response = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "user", "content": "Fact-check: The Earth is round"}
    ]
)

print(response.choices[0].message.content)

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Error Handling

The API returns standard HTTP status codes and detailed error messages:
  • 200: Success
  • 400: Bad Request - Invalid parameters
  • 401: Unauthorized - Invalid or missing API key
  • 422: Validation Error - Request data validation failed
  • 429: Too Many Requests - Rate limit exceeded
  • 500: Internal Server Error - Server-side error
{
  "detail": [
    {
      "loc": ["body", "model"],
      "msg": "field required",
      "type": "value_error.missing"
    }
  ]
}