Anthropic API vs OpenAI API

Side-by-side pricing, features, and free plan comparison — everything you need to choose between Anthropic API and OpenAI API.

Feature	Anthropic API	OpenAI API
Starting price	Pay-as-you-go	Pay-as-you-go
Pricing model	usage	usage
Free plan	Yes	Yes
Free trial	No	No

Frequently asked questions

Verified May 2026.

What is the difference between Anthropic API and OpenAI API?

Anthropic API: API access to Claude 3.5 and Claude 4 models with a 200K context window. OpenAI API: API access to GPT-4o, o3, and other OpenAI models via REST.

Which is cheaper, Anthropic API or OpenAI API?

Anthropic API starts from Pay-as-you-go. OpenAI API starts from Pay-as-you-go.

Does Anthropic API or OpenAI API have a free plan?

Anthropic API: Yes, free plan available. OpenAI API: Yes, free plan available.

Affiliate disclosure: some links on this page earn us a commission if you sign up. Pricing verified manually.