bbitter / profile

I'll be speaking at the first ever FastAPI Conf on October 28th in Amsterdam! 🇳🇱 I'll be sharing how Space Telescope Science Institute uses FastAPI! 🔭 I'm super honored to be included in this amazing speaker lineup. Check it out! fastapiconf.com #Python #FastAPI

Beware people obsessed with outcomes instead of building outcome machines. Its worse than ever with AI, but these people existed before. Short term results above all else, etc. Don't fall into the trap. Invest in building strong fundamentals, invisible supports, and outcomes flow like water. An outcome machine.

Come and learn how typing.Annotated works underneath from @fvoron at FastAPI Conf. 🤓 Learn things you won't learn anywhere else. Join us in Amsterdam! 🚲️ fastapiconf.com/speakers/#fran…

The next frontier model benchmark should be to generate the minimal diff while still achieving the goal.

Calling Europe’s Future Founders! On 16 September, AI Innovate kicks off in Stockholm — the first stop in our new event series connecting the people shaping what comes next in AI. As part of the event, we’re hosting a hackathon with support from our partners @Lovable , @polar_sh and KTH AI Society. Applications are now open here: app.builderbase.com/event/accel-ai… Bring your ideas. Build something ambitious. Meet fellow founders, builders and AI enthusiasts from across Europe. What are you waiting for?

3 → 17 employees in 1 year! ✨ This week, we're hanging out in Berlin & celebrating growing our fantastic team to 17 people, and planning out the next evolution of Polar. We have big plans in store for the next few months. We're hiring btw.

if you see the @polar_sh team in Berlin this week, don’t be a stranger 💫

Guten tag 👋 So excited to gather with the @polar_sh team in Berlin this week!

Most developers know that avg latency is misleading and they should use percentiles instead. They also know that if 90tile response time is 200ms, then 10% of the requests had response times higher than 200ms. Well, the last sentence is false. Or rather, true in theory. The only way to calculate true percentiles is by sorting and scanning all the data. Since this often means many millions of datapoints, we actually don't do that. We approximate. With histograms. How does that work? You create buckets of values: 0 to 0.05, 0.05 to 0.25, 0.25 to 1, 1 to 5, 5 to infinity. Then you accumulate: number of data points, sum of values and the number of data points that fall in each bucket. Now, if I ask you for the 90tile value, you start going over the buckets from lowest to highest latencies, and add the number of points in each bucket. Once you go past 90% of the data points, you know that your 90tile value is in this bucket. Then you give either the middle of the bucket or the upper bound as the estimate. Note that you don't know what % of the data is higher than the estimate. And also note that the quality of the estimate really depends on how the data ends up distributing between the buckets. It isn't uncommon for ntiles 90, 95 and 99 to all fall in the same bucket (if your distribution is "heavy tail"). And sometimes all or most of the data falls in one bucket and you can tell nothing. I recently had a case where we noticed the 99tile of response time for a specific request type was 10s. This was both high and suspicious - we have a 10s timeout in some places. But we couldn't find any request that hit these timeouts in our logs. Super weird! Until a smarter colleague realized (by looking at sample traces) that 10s was just the lower bound of the top bucket. The requests actually timed out at 60s. This allowed me to find the timeout they actually hit and fix the issue. So the lesson is: Averages are misleading. But percentiles are usually approximate and can be misleading too! Be careful not to trust the data blindly. #StatisticsSaturday

Look, all the cool kids are coming. ...and I'm coming too, to make jokes for the cool kids and for you, keep you entertained. Why don't you join us too? FastAPI Conf will be fun.

@FastAPI Cloud is coming to Amsterdam! 🇳🇱 The team behind @FastAPICloud is organizing FastAPI Conf 2026 (featuring @pydantic, @openai, and more!), and we're very happy to spend a full day with the community in person. If you're around, come say hi! 👋 October 28th // fastapiconf.com

Help save the Royal Wing 👇 collecte.chambord.org/?locale=en

Every time I return to @domainechambord, I’m struck by the same sense of wonder. Proud to be a patron of the restoration of the Royal Wing, and to play a small part in preserving such an extraordinary piece of history 🏰

FastAPI Conf speaker news! 📢 @jxnlco, creator of Instructor, the person that convinced AI Labs to provide structured output with Pydantic (automatic compatibility with FastAPI). He's bringing us some insights directly from the Codex team at @OpenAI 🤖 fastapiconf.com

yes, i never will get tired of this feeling 🤌🏻 postbro.co

We used infrared ports to spend 20 minutes sharing an MP3 in person only to discover it failed at a 2m mark.

We’re doing it @polar_sh several times a day, combined with @sentry MCP, and using @stillaai agent on Slack. Game changer.

We’re switching TOTP on @polar_sh from SHA-256 to SHA-1. Not because it’s better, but because some major authenticator apps (hey @Authy, @Okta Verify) ignore the algorithm parameter and silently generate SHA-1 codes anyway 🤦‍♂️ The result: rejected codes and confused users.

Bringing JS to the server was a huge mistake 😏

FastAPI Conf news! 📢 @marcelotryle, maintainer of Starlette and Uvicorn, the web components behind FastAPI, will join us as a speaker in Amsterdam! 🙌 Get your tickets: fastapiconf.com