You can host dynamic or full-stack applications for free using several modern platforms that offer generous free tiers. These services are ideal for personal projects, demos, and MVPs.

### Top Free Hosting Platforms for Dynamic Apps

*   **Render**: A popular choice for full-stack apps. It supports Node.js, Python, and other backends, offers free SSL, a global CDN, and auto-deploys from Git. The free tier includes 750 hours of runtime per month and idles after 15 minutes of inactivity.
*   **Fly.io**: Deploys apps in microVMs across a global network. Its free tier provides 256MB RAM (2 instances) and 1GB persistent storage, suitable for small applications.
*   **Replit**: An in-browser IDE that allows you to build, host, and deploy dynamic apps directly. It supports multiple languages and is great for prototyping, though not ideal for high-traffic production apps.
*   **Glitch**: Best for Node.js and Express apps. It offers a collaborative environment and 1000 hours of runtime per month for free. Apps may sleep after inactivity.
*   **Railway**: Provides a containerized environment for deploying full-stack apps. The free tier has usage limits, so monitor your consumption to stay within the free plan.

### Serverless & Backend-as-a-Service (BaaS) Options

For a modern, scalable approach, combine frontend and backend services:
*   **Frontend**: Host on Vercel or Netlify (free for static sites and serverless functions).
*   **Backend/API**: Use Cloudflare Workers or Vercel Serverless Functions.
*   **Database & Auth**: Use Supabase (free PostgreSQL, auth, storage) or MongoDB Atlas (free cluster with 512MB storage).

This architecture is cost-effective, scalable, and commonly used for free full-stack deployments.