---
title: "Monitor Ruby on Rails sites"
canonical: "https://lemwatch.com/monitor/rails"
framework: "Ruby on Rails"
last_verified: "2026-08-11"
source: "https://lemwatch.com"
---

# Monitor Ruby on Rails sites

Monitor Rails sites for 500s, Action Cable drops, and asset pipeline 404s.

## Common failure modes

- Asset fingerprint mismatch after deploy (404 on CSS/JS)
- Sidekiq queue backlog ballooning quietly
- ActionMailer SMTP timeouts during traffic spikes

## Typical hosts

- Heroku
- Render
- Fly.io
- self-hosted Passenger

## How we fingerprint this stack

X-Powered-By or csrf-token meta tag with Rails signature

_Canonical HTML page: https://lemwatch.com/monitor/rails_