Jeff Dean

Co-founder & CEO of Discovery Loop. Former Chief Scientist, Google. Helped build many Google products, TPUs, Gemini, TensorFlow, MapReduce, Bigtable, ...

[Jeff Dean @JeffDean]

In April, '17, @jsomers of @NewYorker reached out & said he wanted to do a small profile of me & my longtime colleague Sanjay Ghemawat, watch us work for a few hours, maybe dinner, etc.

It came out today. I think it captures our working style really well. https://t.co/cRSMiFfwAP

[Jeff Dean @JeffDean]

Very sorry to hear this news. 😥

I never had the chance to meet Margaret Hamilton, but her contributions to the flight software that got us to the moon are legendary. I love this image of her standing next to the printouts of the Apollo code.

[Massachusetts Institute of Technology (MIT) @MIT]

We’ve lost an icon. Margaret Hamilton, a computer science pioneer best known for her work at MIT leading development of the flight software for the Apollo missions to the moon, has died at 90. Read about her legacy via MIT News: https://t.co/ODkbdIsoHw

[Jeff Dean @JeffDean]

@amnigos @CoughranBill @atomicworkhq Thanks for the coffee!

[Jeff Dean @JeffDean]

@imgmgo @tekbog Hey, our deck is fancy! It has a blue stripe at the top!

[Jeff Dean @JeffDean]

@docmilanfar @theNAEng Congrats on the well-deserved induction! The induction weekend was super fun because you get to meet so many interesting people across many fields!

[Jeff Dean @JeffDean]

@siddharthaa7 @amnigos Great meeting you!

[Jeff Dean @JeffDean]

@PaulYacoubian @siddharthaa7 @amnigos ?

It is.

[Jeff Dean @JeffDean]

@ashwaniapex Having posted a similar badge + laptop photo recently (nice stickers!), I want to wish you all the best! It was a pleasure working with you over many years, and I'm certain you'll do amazing things in the future!

[Jeff Dean @JeffDean]

@theworldlabs @AMD Congratulations, @drfeifei and everyone else at World Labs, and also to @LisaSu and AMD! What a great combination!

[Jeff Dean @JeffDean]

Proud to have collaborated with many others on quite a few of these things!

[Deedy @deedydas]

claude just generated this 2 minute video about the history of Google and it goes so goddamn hard

[Yun S. Song @yun_s_song]

We are excited to announce a new faculty position in AI for Biology at UC Berkeley, jointly between @Berkeley_EECS and @CCBBerkeley.

Please repost & share this opportunity with outstanding early-career researchers in your networks.

Apply by Nov 9, 2026: https://t.co/9UCbg4wKON

[Jeff Dean @JeffDean]

@rajiinio @Berkeley_EECS @StanfordHAI @the_IAS @beenwrekt Congratulations! 🎊

[Jeff Dean @JeffDean]

@yuncuntu Another commenter also asked about this:

https://t.co/IBJwT8PMRO

[Jeff Dean @JeffDean]

Good question. It compares human drivers with Waymo driving from the areas where Waymo operates (to normalize for driving conditions, weather, etc)

There's more about the methodology here (this paragraph is from section 1.1.5 of the FAQ portion of the page below).

https://t.co/sVzh0fLzLj

[Jeff Dean @JeffDean]

The safety data for Waymo gets better and better.

Comparison w/ human drivers on rate of crashes with serious injury:

Latest data: 270M miles, 20X better
Mar 2026: 170M miles, 13X better
Before that (forget exactly when): 10X better

[Waymo @Waymo]

270M+ miles. 841 fewer injury-causing crashes.

Our latest safety data shows the Waymo Driver continues to make roads safer for everyone.

Compared to human drivers across 5 territories, it reduced:
📉 Injury crashes by 82%
📉 Serious injury crashes by 95%

Full data: https://t.co/Y0RVuJLMS5

[Jeff Dean @JeffDean]

Good question. It compares human drivers with Waymo driving from the areas where Waymo operates (to normalize for driving conditions, weather, etc)

There's more about the methodology here (this paragraph is from section 1.1.5 of the FAQ portion of the page below).

https://t.co/sVzh0fLzLj

[Milos @milos_gis]

Every French🇫🇷 passenger train, on an ordinary Tuesday, from first departure to last

[Jeff Dean @JeffDean]

This was recorded a few months ago when I was still at Google and it was a really fun conversation!

[Warren Redlich - Chasing Dreams 🇺🇸 @WR4NYGov]

How does this only have 21,000 views in 8 days?

Chat with @JeffDean (then Google) and Bill Jia about large scale AI models.

https://t.co/XowIkSZxY7

[Jeff Dean @JeffDean]

Did you know you can learn interesting things from computations in real rat neurons? I love what @AlexKsendzovsky and team are doing at @BioComputingCo are doing.

[Alex Ksendzovsky @AlexKsendzovsky]

What happens when neurons meet silicon? A new world emerges.

Partnering with Amazon to bring it to customers. DM me for early access.

[Lucas Bleme 🌯 @andreybleme]

Luiz André Barroso’s work influenced me a lot in how I think about systems, and even about my career.

I decided to write about his work with @JeffDean on some topics that interest me a lot: tail latency and the systems behind the modern internet. https://t.co/wIzMXBtJXK

[Jeff Dean @JeffDean]

@andreybleme Thanks for writing this! Luiz was an amazing colleague and we all miss him dearly!

[Jeff Dean @JeffDean]

Thanks for the great discussion, @dawnsongtweets!

[Dawn Song @dawnsongtweets]

I had the great honor and pleasure of sitting down with @JeffDean for his first public talk since leaving Google, where he spent an extraordinary 27 years.

Few people have shaped modern computing and AI as profoundly - from MapReduce and Bigtable to TensorFlow, Mixture-of-Experts, TPUs, and Gemini.

Our conversation covered some of the biggest questions shaping the future of AI:

• How do you recognize a foundational idea before everyone else does?
• How do you choose a research problem worth spending 5 years on?
• What can coding teach us about building better reasoning models?
• What might recursive self-improvement (RSI) actually look like?
• What happens when the scientific discovery loop itself becomes increasingly automated? (and how is Jeff’s new startup going to contribute in this space?)
• As AI becomes increasingly autonomous, how do we keep it safe and secure?
• What should the next generation of researchers be working on?

Here are some key insights and highlights for anyone building the future of AI. 🧵1/8