The endpoint /stats?username=xxxx&theme=x currently sends response.svg (the SVG file which is saved in the root directory after rendering the SVG object created using SVGwrite library) as a response.
This approach is inefficient.
I suggest sending the SVG object as a response to the endpoint instead of saving a SVG file.

Application error
An error occurred in the application and your page could not be served. If you are the application owner, [check your logs for details](https://devcenter.heroku.com/articles/logging#view-logs). You can do this from the Heroku CLI with the command
heroku logs --tail

This seems to have stopped working on HeroKu

The user info API of codeforces also returns titlePhoto which contains the address to the user profile picture.
Currently, this project only renders an emoji instead of the user profile picture.

What I suggest is we render the user profile picture to the stats card instead of an emoji.
Please respond if you're willing to take on this issue.

When I do it for my profile https://codeforces-stats-api.herokuapp.com/stats?username=sahilgarg&theme=1 it is giving me internal server error.