Running a full-stack Rails project locally means at least four services: Rails server, Sidekiq, frontend build, and CSS watch. The old approach was four terminal tabs or foreman to bundle them together.

After using foreman for a while, a few things got to me: log colors disappearing, output delayed by several seconds, and one dying process taking down everything else. Overmind fixes all of this — and adds a few features that become hard to live without.

What Is a Procfile

Overmind reads a Procfile, a format popularized by Heroku that defines which services your application provides and what commands to run them:

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web: bin/rails server
worker: bundle exec sidekiq
assets: yarn build --watch
css: yarn tailwind --watch

One line per service, format is name: command. This file also works as deployment config on Heroku, Render, and Railway — same file locally and in production, fewer environment mismatches.

Installation

On macOS, install tmux first (Overmind’s core dependency):

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brew install tmux
brew install overmind

On Linux:

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apt-get install tmux
# Download the latest release binary, or:
go install github.com/DarthSim/overmind/v2@latest

Basic Usage

In any directory containing a Procfile:

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overmind start
# or the short alias
overmind s

All services start up with their log output collected in one stream, each process name color-coded.

Features That Make the Difference

Restart a Single Process

I use this daily. After changing a Sidekiq worker, I don’t need to stop and restart the whole stack:

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overmind restart worker

Only worker restarts. Web and frontend build keep running uninterrupted.

Connect to a Process

Need to interact with a process directly — check output or type a command:

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overmind connect web

This opens a tmux window attached to that process. Press Ctrl+b d to detach without stopping it.

Let a Process Die Without Killing Others

A frontend build that exits when done shouldn’t tear down the whole stack:

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overmind start -c assets,npm_install
# or via env var
OVERMIND_CAN_DIE=assets,npm_install overmind start

Auto-restart

For processes that occasionally crash:

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overmind start -r worker
OVERMIND_AUTO_RESTART=worker overmind start

Use all to auto-restart everything:

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overmind start -r all

Why Logs Don’t Get Clipped or Delayed

foreman’s log issues come from how processes detect their output destination. When a program’s stdout isn’t a real terminal, it switches to buffered mode — color escape codes get stripped and output batches until the buffer fills.

Overmind runs each process in a real tmux window and uses tmux’s control mode to capture output. From the process’s perspective it’s writing to a terminal, so colors stay intact and output is immediate.

Environment File Configuration

Rather than typing long flags every time, create .overmind.env in your project:

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OVERMIND_PORT=3000
OVERMIND_AUTO_RESTART=worker
OVERMIND_CAN_DIE=assets

Overmind reads this automatically on start. You can also put global settings in ~/.overmind.env.

Port Assignment

Overmind sets the PORT env variable for each process automatically:

• First process: PORT=5000
• Second: PORT=5100
• And so on (step defaults to 100)

Use it in your Procfile:

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web: bin/rails server -p $PORT

Change the base port:

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overmind start -p 3000

Reference another process’s port:

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web: bin/rails server -p $PORT
proxy: ngrok http $OVERMIND_PROCESS_web_PORT

Running Only Some Services

When you only need web and worker, not the frontend build:

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# Run only specified services
overmind start -l web,worker

# Exclude specified services
overmind start -x assets,css

Scaling

Run multiple instances of a process:

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overmind start -m web=1,worker=3

Three worker instances start with ports assigned sequentially.

foreman vs Overmind

The main tradeoff is the tmux dependency. If tmux isn’t available or you only need basic Procfile management, the same author built Hivemind — no tmux integration, but no log problems either.

A Real Procfile Example

Rails + Sidekiq + Vite:

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web: bin/rails server -p $PORT
worker: bundle exec sidekiq -C config/sidekiq.yml
vite: bin/vite dev

With .overmind.env:

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OVERMIND_PORT=3000
OVERMIND_AUTO_RESTART=worker
OVERMIND_CAN_DIE=vite

Start everything:

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overmind s

Three services, each in their own tmux window, colors intact, worker auto-restarts on crash, vite can exit without taking down the rest.

References

• Overmind GitHub Repository
• Hivemind — Lightweight Version (no tmux)
• Introducing Overmind and Hivemind — Evil Martians
• Heroku Procfile Format