One question,
two answers.

Your question goes to OpenAI and Anthropic at the same time. Read the answers side by side, keep talking to either or both, and have them check each other’s work.

Try one

OpenAI
Anthropic

Settings

API keys

Keys are saved only in this browser and are sent only to api.openai.com and api.anthropic.com. Use keys with a monthly spend limit, and enter them again on each device you use.

Models

Pick from the list or type any model ID. Check a key above to load every model your account can use.

Research

Cross-check

Cross-check sends each model the other’s latest answer, asks where they agree and disagree, and gets a revised answer. More rounds turn it into a back-and-forth debate.

{other} becomes the other provider’s name, {answer} its latest answer.
Advanced

Your chats

Chats are saved in this browser only. Export them to move them to another device.