How to Build a Web App in 2026: A Founder Guide (No Code to Full Stack)

To build a web app in 2-8 weeks, follow a structured process. Before writing code, validate the idea by creating a landing page and testing demand. Define the core loop and focus on a minimal viable product (MVP) with exactly 3 screens. Use Next.js 15 + Firebase for a scalable and fast stack. Prioritize tasks and deliverables for each week.