Pycon NL keynote: believe in routes - Marcelo Trylesinski¶
(One of my summaries of the 2026 one-day Pycon NL conference in Utrecht, NL).
Routes: not every route starts the way people think. Here’s his route through life.
You might know Marcelo from uvicorn, fastapi, starlette, logfire, Pydantic AI, MCP Python SDK, httpx2… It started for him in 2017 when he played league of legends for a full semester and failed all courses. This closed his main route: graduating on time and getting the expected job. Instead he got a good-enough job somewhere in Florianópolis (Brazil).
What was your closed route? It might be a degree you didn’t finish. A field that changed under you. A job you didn’t get. A move.
One thing he wants to talk about: curiosity needs a direction. You might be curious, but where does it get you? You might have a direction (like a degree plus the expected job), but direction alone, what does it get you? But if you have both curiosity and direction: that’s nice.
Marcelo was curious in open source. What helped him a lot was to get involved. With open source you can look at issues and start fixing them and slowly getting more and more involved.
In 2020, the web question in python was “Django or Flask”. He picked the third option: FastAPI, and started using it for his job. That resulted in bug reports or feature requests from colleagues that he then could fix in FastAPI itself. He even took over maintainership of python-multipart: by asking the not-really-active-anymore maintainer. Marcelo got the maintainership because he was already known in the community through his other open source work.
Asking can chance your path, just like with the maintainership of python-multipart. Likewise, he asked for a job at Pydantic though his open source contacts. And got it! He works for Pydantic ever since.
What can you open if you want to change your route? What can you do? Is it too late to:
Start contributing to open source?
Learn a new language?
Pick up a hobby?
Change careers?
According to Marcelo, it is never too late. One thing he’d focus on is fun. Have fun with open source, for instance, in his case. It almost started out as his hobby. And he likes AI right now. One of the things he’s having fun with right now is zttp, an IO-less HTTP parser for Python with a Zig core. He mentioned that AI helped him experiment. Another project is pgtask, a Postgresql-native durable task queue + workflow engine.
A big part of his personal workflow is to look at his github notifications for all his projects. Just look at one notification (and thus one issue or PR) at the time and to bring it a little step forward, one at a time.
Normally he handled between 300 and 700 pull requests per year. This year it is already above 2500 (due to AI). Like many maintainers, the workload has gone up. He noticed he actually made noticeably fewer releases this year, though.
Maintainance is a form of care. Care and feeding for your projects. Triaging issues, reviewing PRs, saying “no”, closing the noise. You’re a maintainer, too. Anything that only works because someone shows up. It might be your own life, your family, your club, your project.
Marcelo once got the tip to grow on three tracks at once. Don’t ignore any one of them, you need them all:
Professionally: grow in your job.
Personally: family, relationships, friends.
Healthily: exercise and nutrition. Body and mind.
You might notice that one of those three tracks is starting to eat the others. You can’t remember the last day without a laptop, for instance. Or you spend a year at home on open source and tell yourself it’s fine.
He made a comment about AI. He works on AI tools every day. He still doesn’t know where it goes. He knows some of the routes might be closing for you because of AI. As a maintainer, he actually uses AI. He lets AI review pull requests, he lets it write his one pull reuqets. Security advisories. But AI doesn’t diminish his enthousiasm and curiosity.
Remember the bring it a little step forward, one at a time he mentioned before? Your route will be different from Marcelo’s. But the only thing you need to get further along on your own route is to move a little step forward every time.
Unrelated photo from our Nelen&Schuurmans company trip to Cologne/Köln in Germany. The salad I had for lunch on Saturday was tasty.