OpenAI DevDay 2026 will be held in San Francisco on 9/29

OpenAI’s official announcement on April 29 states that DevDay 2026, the flagship developer conference, will be held on September 29 in San Francisco, returning to an in-person format after years of absence. Also announced alongside it is a submission campaign: developers use GPT-5.5 and Image Gen to create works and submit them. Each week, Codex will select 2-3 creative submissions, and the winners receive free DevDay tickets (including cross-city airfare and hotel costs).

Conference theme: A developer ecosystem built around GPT-5.5 + Image Gen

The core application stack for this DevDay clearly centers on GPT-5.5. GPT-5.5 launched on April 23 and its API was fully opened on April 24. By the end of April, GPT-5.4 Pro also showed tangible results in both bioinformatics and mathematics research scenarios (the most talked-about being that on 4/28, 23-year-old amateur researcher Liam Price solved the 60-year-old Erdős conjecture #1196 using GPT-5.4 Pro). OpenAI schedules DevDay about 5 months after these two developments, giving the developer community enough time to accumulate application cases built on the new model—an example of a “lead with the model, then hold the big conference” timeline.

The submission campaign design is also attention-grabbing: entries are automatically filtered by Codex, effectively embedding OpenAI’s code agent product into the event’s evaluation logic. On one hand, this showcases Codex’s capabilities publicly; on the other, it makes “human-machine collaborative judging” the implied underlying theme of DevDay.

Participation eligibility and follow-up observations

Official rules for the submission campaign: participants must be at least 18 years old; OpenAI employees, contracted partners, and their direct family members are not allowed to participate. There is one drawing per week, and the drawing period runs until before the DevDay opening ceremony. The specific registration method and evaluation criteria will be published on OpenAI’s event page.

For the global developer community, this DevDay marks OpenAI’s first return to an in-person conference after the 2024 event (in 2025, it shifted to an online program). Key things to watch include: whether a new-generation flagship model will be announced in September (GPT-6 or a successor to GPT-5.5), whether agent products such as Codex and ChatGPT Workspace Agents will see further integration, and OpenAI’s concrete plans for its cloud partnerships with Microsoft and Amazon (after the April 27 re-signing of the agreement, OpenAI can run across multiple clouds).

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