Blake Embrey (@blakeembrey) header
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Building. Previously @Opendoor, @MuleSoft, TS Node, Typings, Express.js TC.

San Francisco, CA
Joined June 2010
Photo by Blake Embrey (@blakeembrey)Photo by Blake Embrey (@blakeembrey)Photo by Blake Embrey (@blakeembrey)Photo by Blake Embrey (@blakeembrey)Photo by Blake Embrey (@blakeembrey)Photo by Blake Embrey (@blakeembrey)Photo by Blake Embrey (@blakeembrey)Photo by Blake Embrey (@blakeembrey)Photo by Blake Embrey (@blakeembrey)Photo by Blake Embrey (@blakeembrey)
Blake Embrey retweeted
A technical dive inside our new "Midjourney Scanner"
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Had a Jane Street interview in 2014 End of round 5. Interviewer says "round 6 will find you." Three weeks. Nothing. I'm in line at the Trader Joe's on 14th. Line snakes past the frozen aisle, the way it always does. I'm holding a bag of orange chicken and a four-pack of cold brew concentrate. Guy in front of me is in a Patagonia vest over a quarter-zip. Not turning around. Inching his cart forward every 30 seconds. Picks a box of something out of his own cart. Holds it up over his shoulder without turning around. "Ant on a corner of this box. Walks to the opposite corner along edges. How many shortest paths." "Six." "Now in 4 dimensions." I think. Tesseract. One edge per dimension, any order. "4!. Twenty-four." "Confidence." "0.85." "Correct on both counts." Offer Monday. $69k base (which I'm told is a 'cultural fit discount'). No bonus. No equity. No relocation. They will, however, allow me to name one (1) colocated server in their NY4 cage. I take my time. This is the only thing I'm being given. I submit "Steve." Already a Steve. I submit "Steve2." Discouraged naming pattern. I submit "Steven." Confusing with Steve. I submit "Big Steve." Big Steve exists in NY5. I submit "my Steve." Approved. Two weeks into onboarding, IT pings the eng channel: "my Steve is down." Three engineers respond at once asking which Steve. The thread spirals. Someone clarifies: "it's named 'my Steve.'" Someone replies "yes but whose." A VP joins the thread: "is this a possessive or a proper noun." Nobody knows. A meeting is called. The meeting is titled "re: my Steve." Nine engineers attend. The first ten minutes are spent establishing whether the meeting title refers to the server or to a Steve belonging to the meeting organizer. The meeting organizer is named Devesh. Devesh does not know a Steve. Offer rescinded Friday. Reason listed in the email as: "Introduced ambiguity into production naming taxonomy. Unrecoverable." I'm no longer allowed in the building. I am also, somehow, no longer allowed in the Trader Joe's on 14th. The doors don't open for me. I have tested this six times. The orange chicken is still in there. Three bags deep on the shelf, frozen, waiting. I think about it every day.
Jane Street made ~$40B in 2025 with 3,500 employees, a ~2x from the year before. At ~65-70% profit margin, that's $8M profit / employee, the highest for a 1000+ ppl company. High-frequency trading continues to be the most efficient money making engine. I want to share an old story about my Jane Street interview in 2014. Jane Street was known for hiring a lot of math, physics and CS olympiad winners from top universities and putting them through many rounds - including, for trading roles, a gauntlet of mental math. It was my 6th interview and my final round and I recall being asked "What is the next day after today in DD/MM/YYYY where all the digits are unique?" They'd toy with you and say "You can use a pencil and paper, if you want" but you knew that was an instant no. Painstakingly and as quickly as I could, I came to an answer. "How confident are you that this is correct on a 0-1 probability scale?" the interviewer said. "0.95", I blurted out, not fully knowing how to answer that. "Are you sure?" After thinking harder for a few more seconds, I realized I could've flipped the digits around to get a closer date. I gave the interviewer my answer. It was correct. "0.95 huh?" he chuckled. That's when I knew I failed. Note: fwiw, other companies that come close in efficiency are - Tether ($90M+ profit/emp) - Hyperliquid ($80M+ profit/emp) and on revenue: - Valve ($50M/emp) - OnlyFans ($37M/emp) - Craigslist ($14M/emp) - Anthropic ($12M/emp, run rate) - OpenAI ($8M/emp, run rate) For comparison, Nvidia is very efficient at scale and is $4.4M/emp.
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WAIT!!! ALL THIS WAS JUST LAST WEEK IN TECH???
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I can do a flip. Not a big deal. #INSTACARTPARTNERS
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Apple has landed the rights to turn ‘MISTBORN’ into a film franchise & ‘THE STORMLIGHT ARCHIVE’ into a TV series. Brandon Sanderson will write, produce and consult on all projects. (Source: hollywoodreporter.com/movies…)
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Hangzhou is insane. Just look at what these kids do. They casually made a fleet of trash-catching trash cans for a 3 minute video. 232 likes as of now. And all their stuff is like this.
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Got the new @daylightco for comfortable reading
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👀 @fastifyjs cookie is using the cookie package Amazing turnaround on putting out a new major release for this.
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One of my favorite open source interactions, y'all are too kind teapawt.net/gurgund4y/status/18437… It was only a week ago I found the initial perf boost that piqued my interest with github.com/jshttp/cookie/pul…
The cookie package, 50M+ weekly downloads, is getting some love (and a noticeable perf boost) thanks to @blakeembrey
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Excited to finally publish some ReDoS work I spent the last few months agonizing over blakeembrey.com/posts/2024-0… Good news, it's most a non-issue in the wild!
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Advanced Physics Department's Christmas tree
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1,000 day streak using @readwise 🎉
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"I think a life properly lived is just learn, learn, learn all the time." — Charlie Munger
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I'm not a physical book guy so I must give away this signed edition of @EricJorgenson's new book: The Anthology of Balaji. As always, I'll throw in some @readwise holographic stickers and a tee as a bonus😛 Retweet and I'll pick someone at random in 3 days (Oct 30)!
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Honored to get a mention alongside @basarat teapawt.net/basarat/status/1704987…
The TypeScript Origins Documentary is out. Glad I got a mention even though they couldn't fly all the way to the land down under to interview me 😅🌹
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Updated my plot of bank failures. 😬 observablehq.com/@mbostock/b…
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Introducing Vercel Storage ◆ Vercel Postgres: Serverless and Edge-ready SQL ◆ Vercel KV: Durable, global, serverless Redis ◆ Vercel Blob: Fast, simple file storage vercel.com/blog/vercel-stora…
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REMIX or RIPOFF? 🧵 The Fifth Element (1997) Frida Kahlo (1944) 1/55
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