How does OpenAI API compare with the alternatives?
GPT-6.1 Sol scores 55 on the Artificial Analysis Intelligence Index v5.0 (Oct 27, 2026) at US$1.27 per task, against US$10.02 for Sonnet 5.5 at the same list price, while Opus 5.5 holds the top score. Test both with caching on.
Wealthsimple and DoorDash run both behind one gateway. GPT-6.1 Sol outscores Gemini 4 Argon and Gemini 3.8 Flash on the Artificial Analysis Intelligence Index v5.0 (Oct 27, 2026) at a lower cost per task, and Argon's introductory price ends on November 30, 2026.
DoorDash and Grab keep Azure OpenAI as a second route to the same models. Buy from OpenAI for release-day features and a hard spend cap; choose Azure OpenAI when your Microsoft contract or data processor rules decide it.
Codex is a finished coding agent. The API with the Agents SDK, or the Agents API that runs the Codex harness, is how a platform team builds its own on the same OpenAI models. Buy Codex for engineers' daily coding, and build on the API when the agent belongs inside your product.
