GPT-5.5 just landed on AWS, ending Microsoft’s seven-year lock on OpenAI

OpenAI’s most powerful model, GPT-5.5, is now running on Amazon Web Services for the first time. The launch comes one day after Microsoft and OpenAI rewrote the terms of their partnership, ending nearly seven years in which Azure was the only cloud platform legally allowed to host OpenAI’s frontier models. AWS customers can now invoke GPT-5.5 — along with GPT-5.4 and OpenAI’s open-weight gpt-oss-20b and gpt-oss-120b — through the same Amazon Bedrock APIs they already use for Anthropic, Meta, and Amazon’s own Nova family, with the option to apply usage to existing AWS spending commitments.

The release is a limited preview, not general availability, with broader rollout expected within weeks. Three things land at once: OpenAI’s models on Bedrock; Codex, OpenAI’s coding agent, accessible through the Bedrock API and the Codex CLI, Codex desktop app, and VS Code extension; and Amazon Bedrock Managed Agents, a new service that wraps OpenAI’s agent harness with AWS-native identity, logging, and tool integrations. AWS is positioning Managed Agents as the production path for companies that want to deploy long-running OpenAI agents without assembling the surrounding infrastructure themselves.

Microsoft and OpenAI restructured their partnership the day before the AWS launch. Azure remains OpenAI’s “primary cloud partner” through 2032, and Microsoft retains a non-exclusive license to OpenAI’s intellectual property through that same year, with a capped revenue share. But the exclusivity that locked OpenAI’s frontier models to Azure for the better part of a decade is gone. AWS becomes the second hyperscaler with the legal right to distribute OpenAI’s enterprise platform, and the rapid sequence of moves — Microsoft amendment one day, AWS preview the next — suggests the integration was being prepared months in advance.

For developers, the practical impact is procurement, not technology. OpenAI’s direct API has always been available — but enterprises with multi-million-dollar AWS commitments could not apply that spend to OpenAI usage, and security teams had to vet a separate vendor relationship. Bedrock erases both frictions. OpenAI inference on Bedrock inherits AWS IAM, PrivateLink, guardrails, encryption, and CloudTrail logging by default, and consumed tokens count toward existing AWS Enterprise Discount Programs and savings plans. For large customers, that may be the entire deal: not access to GPT-5.5, but access to GPT-5.5 with the AWS contracts they already signed.

The hype deserves trimming. The launch is limited preview — not all customers can request access yet, and pricing through Bedrock is documented as potentially differing from OpenAI’s direct API rates. Microsoft is not retreating: Azure remains primary cloud partner through 2032, GitHub Copilot, Microsoft 365 Copilot, and Dynamics 365 keep deep OpenAI integrations, and Microsoft’s revenue share continues. The financial scale of the AWS-OpenAI partnership is reported variously as a $38 billion seven-year compute commitment OpenAI signed with AWS late last year and as a $50 billion Amazon investment in OpenAI announced this week — the two figures may overlap, and OpenAI has not published a unified breakdown. And Bedrock already hosts Claude, Llama, Mistral, Cohere, and Amazon’s own Nova family; OpenAI joins a crowded competitive field, not an empty stage.

The cross-cloud move marks a clear stage in the maturing of the AI infrastructure market. Foundation-model providers spent the last three years sprinting toward whichever cloud could supply the most compute fastest; the next phase is distribution, where customers expect to consume models the way they already consume databases or storage — through their existing cloud contracts, with their existing security boundaries. AWS gains a frontier model brand it had been missing on Bedrock. OpenAI gains the procurement pipeline of the world’s biggest cloud. And Anthropic, until now the headline foundation model on Bedrock, becomes one frontier option among several rather than the obvious choice.

GPT-5.5 itself shipped on OpenAI’s direct API on April 23. The Microsoft-OpenAI amendment was announced on April 27. AWS opened the Bedrock preview on April 28, at the company’s What’s Next with AWS event. General availability is expected within weeks, with additional OpenAI models — including GPT-5.5 Pro and the o-series reasoning models — anticipated to follow once the limited preview phase closes.