OpenAI's deepest reasoning model for the hardest problems.
OpenAI o3 is one of the tools our readers ask about most in the coding space. We put it through two weeks of real workflows — here's the honest breakdown of where it shines and where it falls short.
Who it's for: OpenAI's deepest reasoning model for the hardest problems.
o3 spends inference "thinking" tokens to solve competition-level math and proofs.
Top scores on software-engineering benchmarks; great at multi-step refactors.
Can run code and search the web inside ChatGPT for verified answers.
Accepts images, charts, and PDFs as part of the prompt.
OpenAI o3 earns its place in the coding stack if you want a tool that's genuinely better than the free default for serious work. We'd start on the trial,prove it on one real workflow, then upgrade only if it pays for itself.