How do we build a fast API against database models with foreign keys and many- to-many relationships? If you do nothing you get what I call the “waterfall of doom”. At some point in the past someone told me or I read that “joins are effectively free in Postgres”. While this might be somewhat true when you are writing all of the SQL and can control every part of your query; I have recently found that when the database gets big enough and you are using the Django ORM, joins aren’t free and less can be more!

Lucas Roesler

I am senior engineer at and an ex-mathematician. I have worked on web applications, algorithms for image analysis, machine learning problems, and pure math research.

Senior Engineer

Berlin, DE