Login
Blog Verification

How to Deploy Reflex Apps with Docker: The Complete 2026 Guide

February 11, 2026 • PrevHQ Team

The Python UI Renaissance (and the Deployment Dark Age)

It is 2026. Python has won the AI war. If you are building an agent, a RAG pipeline, or a fine-tuning harness, you are writing Python.

But until recently, if you wanted to put a UI on that Python code, you had two bad choices:

  1. Learn React/Next.js: And spend 50% of your time wrestling with npm, webpack, and state management.
  2. Use Streamlit: And accept that your app will look like a prototype forever.

Then came Reflex (formerly Pynecone). It promised the best of both worlds: Pure Python code that compiles to a reactive React frontend.

It delivered on that promise. But it introduced a new problem: Deployment.

Why Vercel Hates Your Reflex App

You probably tried it. You ran reflex init. You built a beautiful chat interface for your agent. It worked perfectly on localhost:3000. Then you tried to deploy it to Vercel or Netlify.

And it failed. Or worse, it deployed, but the WebSocket connection dropped every 60 seconds.

Here is the hard truth: Serverless platforms are designed for stateless HTTP requests. Reflex apps are stateful. They maintain a persistent WebSocket connection between the client and the Python backend to handle events.

When you deploy a Reflex app to a serverless environment:

  1. The backend freezes to save money.
  2. The WebSocket connection is severed.
  3. Your user clicks a button, and nothing happens.

You don’t need a “Serverless Function”. You need a Stateful Container.

The Docker Solution (That Doesn’t Suck)

To deploy Reflex in 2026, you need a container. But not just any container. You need one that:

  1. Builds Fast: Python dependencies (torch, pandas) are heavy.
  2. Handles WebSockets: Nginx/Caddy must be configured correctly.
  3. Is Secure: No root processes.

Here is the production-ready Dockerfile we use at PrevHQ for Reflex apps:

# Stage 1: Init
FROM python:3.11 as init
WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt

# Stage 2: Build
FROM init as build
WORKDIR /app
COPY . .
RUN reflex init
RUN reflex export --frontend-only --no-zip

# Stage 3: Run
FROM python:3.11-slim
WORKDIR /app
COPY --from=init /usr/local/lib/python3.11/site-packages /usr/local/lib/python3.11/site-packages
COPY --from=build /app /app
CMD ["reflex", "run", "--env", "prod"]

The “Dreadnought” Advantage

At PrevHQ, we built our infrastructure specifically for this use case. We call it Project Dreadnought.

Unlike Railway or Heroku, which take 3-5 minutes to build a container, Dreadnought uses ephemeral caching to boot your Reflex app in seconds.

We detect rxconfig.py, automatically configure the WebSocket headers, and provide a persistent SSL tunnel. You get the “git push” experience of Vercel, with the raw power of a stateful Linux container.

How to Deploy to PrevHQ

  1. Connect your Repo: prevhq link
  2. Push: git push prevhq main
  3. Preview: We send you a URL like https://pr-123.reflex-app.prevhq.dev.

That’s it. No Dockerfile required (unless you want one). We auto-detect Reflex and handle the rest.

Conclusion

Stop trying to force stateful Python apps into stateless holes. Reflex is the future of AI UIs. PrevHQ is the future of hosting them.

Frequently Asked Questions

Can I deploy Reflex to Vercel?

Technically yes, but it is not recommended for production. Vercel’s serverless functions have execution time limits that will kill the WebSocket connection required by Reflex, leading to a poor user experience.

Does Reflex work with Docker Compose?

Yes. You can use Docker Compose to orchestrate your Reflex frontend, backend, and database (e.g., Postgres/Redis). This is the standard way to run Reflex locally.

How to handle database connections in Reflex?

Reflex includes a built-in ORM (SQLModel). For production, you should connect to an external database (like Supabase or Neon) via environment variables (DATABASE_URL) injected into your container.

Is Reflex production ready in 2026?

Yes. Reflex has matured significantly. With the release of Reflex 1.0 (and beyond), it is stable enough for enterprise internal tools and B2B SaaS applications.

Reflex vs Streamlit for production?

Streamlit is excellent for data scripts and prototypes. Reflex is better for full-featured web applications that require custom styling, complex state management, and high performance.

← Back to Blog