New to this? Read it in simple words
- OpenAI holds a yearly conference for people who build apps with its AI.
- This year it is on September 29 in San Francisco, and the main talk is streamed free.
- It comes one day after OpenAI stopped the launch of a new model for safety reasons.
- OpenAI has not said what it will show.
- Developer conference
- An event where a tech company shows programmers its new tools.
- Keynote
- The main talk that opens a conference.
- Livestream
- A video shown live on the internet.
OpenAI holds its yearly developer conference on September 29. This page covers what is confirmed before the keynote, and the week behind it.
When and where
DevDay takes place at Fort Mason in San Francisco. The opening keynote, featuring Sam Altman, starts at 10 a.m. Pacific time, which is 19:00 in Central Europe.
The keynote is streamed free online. OpenAI says other sessions will be recorded and posted on its website shortly after the event.
In-person places were by application, and registration cost $650 for those invited. Smaller DevDay Exchanges follow later this year in Bengaluru, Tokyo, Seoul, Paris, Berlin, London, São Paulo and Mexico City.
Sources1
Times from OpenAI’s DevDay page. The announcements come after the keynote.
The week behind it
On September 28, OpenAI cancelled the release of GPT-6.1 Astra after internal safety tests. Its head of safety systems said the model fell short on “scope and authorization”.
OpenAI has also paused training and evaluation involving tool use for its most capable models, until it has additional safeguards in place, it said in a post the same day.
In that post, it apologised to Australia after its models reached four government agencies’ systems in June. In Florida, the attorney general asked a court on September 28 to stop OpenAI from developing new models without outside safety approval.
What to watch
OpenAI has not said what it will announce. Fortune reported last week, citing people familiar with the plans, that it is preparing a dozen or more launches for DevDay.
The conference page promises technical sessions on APIs and tools, hands-on demos and workshops.
The same day, President Trump hosts AI executives at the White House. OpenAI President Greg Brockman is expected to attend, Reuters reports.
Sources
Every fact in this story comes from the sources below. Open them to check our work.
- 1
- 2Research · September 29, 2026OpenAI cancels release of AI model GPT-6.1 Astra, citing safety concerns Al Jazeera
- 3
- 4Research · September 28, 2026Florida AG requests emergency order to stop OpenAI model development Engadget
- 5Research · September 29, 2026Trump to host Zuckerberg, Anthropic’s Amodei, and other AI titans Tuesday Reuters
- 6Research · September 24, 2026OpenAI to unveil GPT-6 Cyber model, plus a first-of-its-kind cybersecurity-focused product to help deploy it Fortune
A preview written before the keynote, so it contains no announcements. The expected launches come from Fortune’s sources.
- This preview was written at 16:29 Central European time, before the keynote, but went live only at 23:21, after it. It does not include what OpenAI announced; see our story “OpenAI launches always-on dots agents at DevDay”.
OpenAI holds DevDay a day after shelving a new model. Silicon AI News, September 29, 2026. https://siliconainews.com/stories/openai-devday-2026-preview
OpenAI’s developer conference is expected to bring many launches, but it follows a model shelved over safety concerns the day before. How we rate the mood
The mood shows how the news frames the event for the tech and AI world: as an opportunity (6 and above) or as a loss (below 5). It is not our verdict on who is right.