Baseten partners with OpenAI to let OpenAI enterprise customers use existing commitments for open models served by Baseten within Codex or via the Responses API
open, closed, or both.Dannie Herzberg /@dannieherz:Baseten is one of the first open model inference providers in OpenAI's new B2B marketplace. This is a huge vote of confidence in open models and in Baseten, and another step toward our mission to help every company own its intelligence. Grateful to the @OpenAI team for being great partners, and s...Philip Kiely /@philipkiely:Enterprise teams can now use open models like GLM-5.3 Flash and Kimi K3 natively in Codex and count spend against their Op
BasetenDannie Herzberg
Context & Ripple Effects
OpenAI had been extending Codex beyond a general coding surface with role-specific plugins, while its open-source agent harness became shared infrastructure for Codex and ChatGPT Work. Baseten's placement brings model choice into those established OpenAI workflows rather than asking enterprise teams to adopt a separate interface.
The arrangement also follows OpenAI's expanded AWS availability deal, which widened the routes through which organizations can consume its technology. Here, OpenAI keeps the enterprise commitment and control surface while Baseten supplies inference for named open models.
First-order effects
OpenAI enterprise customers can apply existing commitments to Baseten-served open models, including GLM-5.3 Flash and Kimi K3, from Codex or the Responses API.
Baseten gains distribution through OpenAI's B2B marketplace and native access to enterprise teams already building on OpenAI's developer surfaces.
Second-order effects
OpenAI can accommodate teams that want open-model workloads without forcing a separate vendor contract or moving that spend outside their OpenAI commitment.
Other open-model inference providers face a sharper incentive to secure comparable marketplace and API integrations, where procurement access and workflow placement matter alongside serving performance.
Third-order effects
The partnership separates the enterprise control plane from the underlying model: an OpenAI commitment can fund third-party open-model inference while users remain in OpenAI's tools.
If this marketplace pattern expands, enterprise AI buying may consolidate around a smaller number of procurement and agent surfaces, with model providers competing to be selectable within them.
The trend: Enterprise AI platforms are evolving from single-model vendors into control planes that aggregate proprietary and open models behind one contract and workflow layer.
OpenAI is betting so hard on the agent layer that they're willing to serve you open models through their surfaces if you want. For general use, OpenAI's models are already extremely competitive on an intelligence per dollar basis, so I don't think this will cannibalize sales too …
OpenAI serving open-source models through Baseten is a big deal. They are embracing open source. Until now, OpenAI's pitch was “use our models.” Now it is “commit your annual AI budget to us
Baseten is now available as one of the first open-model inference providers in the @OpenAI B2B Marketplace. Enterprise customers can use existing OpenAI commitments for open models served by Baseten (Codex or the Responses API). Run what makes sense for your enterprise—open, clos…
Baseten is one of the first open model inference providers in OpenAI's new B2B marketplace. This is a huge vote of confidence in open models and in Baseten, and another step toward our mission to help every company own its intelligence. Grateful to the @OpenAI team for being grea…
The future is both open and closed, and so good to see @OpenAI betting on this with us. Baseten is will be the exclusive open-source inference provider with OpenAI, meaning you can use frontier and optimised open models with existing OpenAI commitments and spend, including a nati…
OpenAI's marketplace is the biggest announcement from the day. You can now buy open-weight model inference from Baseten through OpenAI's responses API (and codex):
It's moves like this OpenAI feels to be pulling ahead of Anthropic. Anthropic is closed everything: closed source Claude Code, no you cannot use other models with CC, and so on. OpenAI: Codex is open source, you can use other models; oh let's make it dead simple to use GLM-5.3:
Huge news from OpenAI DevDay 2026. — Baseten has joined the OpenAI Marketplace. Now, enterprise teams can spend their OpenAI commits on Baseten inference …