Hosting FastAPI on Heroku

Heroku is a paas platform. FastAPI needs roughly 512MB RAM for a production server process, so the cheapest plan that actually fits depends on your traffic. Below is the cheapest Heroku plan that fits each traffic level, computed from current list prices.

Note: the 512MB figure is for serving the built app. Production builds (next buildand friends) are heavier and belong in CI or on your laptop — run them on the same small instance and you'll hit out-of-memory errors that say nothing about its serving capacity.