I've done this solo: My Daily Routine is a production SaaS I designed, built, and launched entirely by myself in about a month — AI-powered routine planning, Paddle payments with verified webhooks, dual auth (Google OAuth + custom JWT/OTP), and a full MongoDB backend. I've also delivered real client apps end-to-end, like Chemistry MCQ Test (an exam-prep platform with timed tests, analytics, and progress tracking) and ShortStack (a production URL shortener with Redis caching, async job queues, and a fully containerized deployment).