Backend

Python with FastAPI is the default for new personal, freelance, SaaS, and open-source projects. Java with Spring Boot stays for enterprise and JVM environments; its standards are TBD.

Page	Covers
Python standards	Version, tooling, typing, naming, environments
FastAPI structure	Feature layout, layers, composition root, Docker
REST API	Versioning, JSON, errors, pagination
Database and migrations	PostgreSQL, SQLAlchemy, Alembic
Logging	Structured logs, correlation IDs, PII

Do not impose these on Flask or Django projects, small scripts, notebooks, or legacy code that follows another established architecture.