Using the OpenAI Models

OpenAI Keys

The grader is based on OpenAI’s API platform which provides access to its powerful GPT models. To use the autograder:

• Go to the OpenAI’s API platform page
• Log In. If you do not have an account, you will be asked to create one
• Go to the API Key page page.
• Create a OpenAI key.
• Go back to the Autograder webpage and paste the key in the OpenAI key box in the top right.

Important notes

• Your API key is never stored on the server. It stays entirely in your browser (using local storage) and is only sent with your grading request so the model can run. The server does not save, log, or retain your key.
• Costs are typically very low. Each grading request uses only a small amount of model compute, so even frequent use should remain inexpensive. You can monitor your usage at any time on your OpenAI dashboard.

Which model to use?

To the right of the Grade button, you will see a dropdown menu to select a model to use. These are my findings so far:

• gpt-4.1.-mini: This is the fastest, about 10-20 seconds for a response. On simple problems, this would be my choice. But, on problems where the model has to reason over multiple clock cycles it makes mistakes.
• gpt-5-mini: This is slower, about 1-2 minutes for a response. But, it can reason very well on more complex problems.

Both models are very cheap. Less than a dollar for a million tokens.