If you look through the comments on this page, it's pretty amazing that almost every single person uses a different tech stack. A non-scientific perusal suggest

If you look through the comments on this page, it's pretty amazing that almost every single person uses a different tech stack. A non-scientific perusal suggests that Python, Django, RabbitMQ, and PostgreSQL are the most common stacks, but this is still a minority. Amazing that after decades of software development on the web, there is still no "best practice" even though many of these web apps do very similar things. In most other mature industries, best practices tend to settle on just a few approaches. Not so for software development.