Performance becomes very slow with multiple users on Reflex app

[ghouse190623-oss]

Title

App becomes very slow with multiple users (backend via systemd + frontend via reflex export)

Description

Hi,

I am new to Reflex and frontend development. I have deployed my Reflex app with this setup:

Deployment Setup

• Backend running as a Linux service:
  reflex run --env prod --backend-only
• _event websocket served from this backend
• Frontend deployed using:
• Exported frontend hosted through nginx
• App uses Reflex state files

Issue

Performance is good with a single user.

But when multiple users use the app at the same time, it becomes very slow:

• 1 user → works fine
• 3–5 users → noticeable lag
• More users → UI becomes very slow / unresponsive

It seems like the single backend websocket process is getting overloaded with multiple sessions.

Questions

1. Is this the correct way to deploy Reflex apps for multi-user usage?
2. Should the backend be run with multiple workers instead of one process?
3. What is the recommended production setup for handling many concurrent users?

Any guidance on how to scale Reflex properly for multiple users would be very helpful.

Thanks!

[masenf]

Couple of things:

1. use redis for production deployments, this allows the server to run in multiprocess mode to avoid getting blocked if some user has a long running event
2. never run blocking code in event handlers. if you have blocking synchronous code, use await rx.run_in_thread to allow the server to continue handling requests while the blocking operation runs.