The one place I'd push back on SQLite: if your app has any write concurrency from external processes (cron jobs, webhooks), WAL mode helps but you still hit lock contention. I have data collection scripts running every 30 minutes that write to the same DB the web app reads from. Postgres handled that cleanly from day one. Neon's free tier is 512MB with connection pooling — more than enough for a side project with real data.