PyDev of the Week: Marcelo Trylesinski

This week we welcome Marcelo Trylesinski (@marcelotryle) as our PyDev of the Week! Marcelo is a core developer of the Pydantic package. You can use Pydantic to enforce type hints at runtime and data validation.

You can catch up with Marcelo on his blog or over on Mastodon. You can also check out Marcelo’s YouTube channel or connect with Marcelo on LinkedIn. If you’d like to see Marcelo’s open-source work, it’s available on GitHub.

Marcelo Trylesinski

Let’s spend some time getting to know Marcelo better!

Can you tell us a little about yourself (hobbies, education, etc):

I’m from Brazil, I was born in Salvador, and lived most of my life in Aracaju. Throughout my life, I’ve had the opportunity to live in several countries, and currently, I’m living in the Netherlands. I’m native in both Spanish and Portuguese, since my mom is from Uruguay, and I’ve also learned to speak English and Italian.

In my free time, I enjoy going to the gym, and recently I’ve taken up bachata and salsa courses and photography, which I’m having a lot of fun. I also enjoy contributing to the open-source community, where I currently help to maintain Starlette and Uvicorn, and I’ve been actively involved with the FastAPI community for three years by now. I like to give talks about Python-related subjects, and share my knowledge with others. On the same line, I also started my YouTube channel.

As for my academic background, I have a Bachelor’s degree in Computer Science from the University of São Paulo. And as a curiosity, while studying there, I worked as a private teacher for the whole time.

Why did you start using Python?

My first interaction with the language was in the end of 2018, on a company called Brick Abode. I remember that my first job with Python was on a web scraper. I also remember that each pull request that I made was followed by around 50 comments from my manager… hahaha In any case, I learned a lot!

After that, I did a machine learning study for my undergraduate thesis in 2019 in Python, and in 2020 I got a job in France (at ReciTAL) that gave me far more experience with the language.


What other programming languages do you know and which is your favorite?

I worked with Java and C at some point, but it’s been almost 4 years without writing a single line on those languages. I’m going to learn Rust, following a lot of Python maintainers.

What projects are you working on now?

In my free time, I’m helping maintain Uvicorn, and Starlette.
As for my working hours, I’m working on Pydantic. And… We just released Pydantic V2!
You can check our migration guide for more information.


Which Python libraries are your favorite (core or 3rd party)?

From the standard library, the typing module is my favorite.
Besides the ones I have some kind of relationship (Pydantic, Uvicorn, Starlette and FastAPI), I think my favorite would be LibCST.


How did you get involved with Pydantic?

I was always “around”, since I’m involved on FastAPI, and Pydantic is one of the core dependencies of it. More directly, I created some small pull requests over the years, but nothing huge.
Recently, I saw the announcement about the company, and I applied for the job… Now, I’m happily working here.


What are your top three tips for someone just getting started with Pydantic?

The documentation is one of the best ones around, so I encourage people to read it.
Use BaseSettings! It’s an incredible useful feature.
Besdies, have fun with it. Pydantic offers a great developer experience, and now, with v2, you’ll have an even better experience.


Thanks for doing the interview, Marcelo!