MAI-1-preview · Microsoft · Model History

MAI-1-preview

Status unknown · Language · Milestone

MAI-1-preview is a mixture-of-experts language model that Microsoft AI calls its first foundation model trained end to end in-house, announced on 28 August 2025. It was offered for public testing on LMArena and to trusted testers through an API, and Microsoft AI positions it for following instructions and answering everyday consumer queries. [1] Primary source

Claims and evidence

Released 28 August 2025Made available on this date for public testing on LMArena and to trusted testers through API access on application, not as a general release. Primary source[1]page date; Try MAI-1-preview in LMArena

Status Status unknownNo current Microsoft source states the status as of 2026-10-01. The announcement of 2025-08-28 described public testing on LMArena and API access for trusted testers; the model is not listed on microsoft.ai/models or in the Microsoft Foundry retirement schedule and retired-models pages. Evidence incompleteNo source

Parameters Not disclosedNot disclosed by Microsoft; the announcement describes an in-house mixture-of-experts model pre-trained and post-trained on about 15,000 NVIDIA H100 GPUs. No claim madeNo source
Access APIAPI access for trusted testers on application. Public testing ran on the third-party evaluation platform LMArena; a rollout for certain text use cases in Copilot was announced as planned over the following weeks. Primary source[1]Try MAI-1-preview in LMArena

Lineage

Predecessors

No known predecessor.

Successors

No known successor.

Based on

Not derived from another model.

Variants and derived

None recorded.

Siblings

None recorded.

All ancestors

None.

All descendants

None.

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