This content originally appeared on DEV Community and was authored by Quinterabok

Complete Fly.io Deployment Guide for Rails App

A beginner-friendly, step-by-step guide to deploying Ruby on Rails applications to Fly.io with Supabase database, custom domain, and email setup.

Table of Contents

1. Prerequisites
2. Part 1: Install Fly CLI
3. Part 2: Set Up Supabase Database
4. Part 3: Deploy to Fly.io (Testing)
5. Part 4: Create Admin User
6. Part 5: Deploy to Production
7. Part 6: Buy and Connect Domain
8. Part 7: Set Up Email Forwarding
9. Part 8: Managing Your App
10. Troubleshooting

Prerequisites

Before starting, ensure you have:

• ✅ A Rails application ready to deploy
• ✅ Git installed and your code committed
• ✅ AWS S3 bucket set up for file storage (or similar)
• ✅ Terminal/Command line access
• ✅ Credit/debit card for domain purchase (~$10/year)

Cost Estimate:

• Fly.io hosting: $5-10/month
• Supabase database: FREE
• Domain name: ~$10/year
• Email: FREE (forwarding)
• Total: ~$70-130/year

Part 1: Install Fly CLI

Step 1: Install Fly.io Command Line Tool

For macOS/Linux:

curl -L https://fly.io/install.sh | sh

For Windows (PowerShell):

powershell -Command "iwr https://fly.io/install.ps1 -useb | iex"

Step 2: Sign Up / Login

# Sign up for new account
fly auth signup

# Or login if you have an account
fly auth login

Follow the browser prompts to complete authentication.

Step 3: Verify Installation

fly version

You should see the Fly CLI version number.

Part 2: Set Up Supabase Database

Why Supabase?

• ✅ FREE tier (500MB database)
• ✅ Automatic backups
• ✅ Great dashboard
• ✅ Saves $38/month vs Fly Postgres

Step 1: Create Supabase Account

1. Go to: https://supabase.com
2. Click "Start your project"
3. Sign up with GitHub, Google, or Email

Step 2: Create Organization (First Time)

1. Enter organization name (e.g., "My Company")
2. Click "Create organization"

Step 3: Create New Project

Fill in the form:

• Name: your-app-name-prod (e.g., name-website-prod)
• Database Password: Click refresh icon to generate
  • IMPORTANT: Copy and save this password!
  • Example: Kx9mP#vL2nQ8wR5t
• Region: Choose closest to your users
  • Southeast Asia (Singapore)
  • West EU (Ireland)
  • East US (North Virginia)
• Pricing Plan: FREE (already selected)

Click "Create new project" and wait 1-2 minutes.

Step 4: Get Database Connection String

1. Click ⚙️ Settings (left sidebar)
2. Click "Database"
3. Scroll to "Connection string"
4. Click "URI" tab
5. Copy the connection string
6. Replace [YOUR-PASSWORD] with your actual password from Step 3

Example final URL:

postgresql://postgres.abcdefghijklmno:Kx9mP#vL2nQ8wR5t@aws-0-ap-southeast-1.pooler.supabase.com:6543/postgres

Save this URL - you'll need it soon!

Part 3: Deploy to Fly.io (Testing)

Step 1: Navigate to Your Project

cd /path/to/your-rails-app

Step 2: Initialize Fly.io App

fly launch --no-deploy

You'll be asked several questions:

Question 1: Copy existing fly.toml?

Answer: N (No) - Start fresh

Question 2: App name

Enter: your-app-test (e.g., name-website-test)

Question 3: Organization

Select: Personal (or your organization)

Question 4: Region

Select: Closest to you or your users (e.g., sin for Singapore)

Question 5: Tweak settings?

Answer: Y (Yes)

Step 3: Configure Settings in Browser

A browser window opens with configuration form:

Fill in:

1. App name: your-app-test (already filled)
2. Organization: Personal (already selected)
3. Region: Keep your selection
4. Internal port: 8080
5. VM Memory: 2GB (select from dropdown)
6. Postgres Provider: Select none (we're using Supabase)
7. Tigris Object Storage: Select Disabled (using S3)
8. Redis: Keep none
9. Sentry: Keep Disabled

Click "Confirm Settings"

Step 4: Set Environment Secrets

Back in your terminal, set your secrets:

Generate SECRET_KEY_BASE:

rails secret

Copy the output.

Set Database URL (from Supabase):

fly secrets set DATABASE_URL="postgresql://postgres.abc:yourpassword@aws-0-region.pooler.supabase.com:6543/postgres" --app your-app-test

Set Rails Secret:

fly secrets set SECRET_KEY_BASE="paste-secret-from-rails-secret-command" --app your-app-test

Set AWS S3 Credentials (if using S3):

fly secrets set AWS_ACCESS_KEY_ID="your-aws-key" --app your-app-test
fly secrets set AWS_SECRET_ACCESS_KEY="your-aws-secret" --app your-app-test
fly secrets set AWS_REGION="your-region" --app your-app-test
fly secrets set BUCKET_NAME="your-bucket-name" --app your-app-test
fly secrets set AWS_ENDPOINT_URL_S3="your-s3-endpoint" --app your-app-test

Verify All Secrets:

fly secrets list --app your-app-test

You should see all your secrets listed (shows digests, not actual values).

Step 5: Update fly.toml Configuration

Open fly.toml in your editor and ensure it looks like this:

app = 'your-app-test'
primary_region = 'sin'
console_command = '/rails/bin/rails console'

[build]

[env]
  PORT = '8080'
  RAILS_ENV = 'production'
  RAILS_LOG_TO_STDOUT = 'true'

[processes]
  app = './bin/rake litestream:run ./bin/rails server'

[http_service]
  internal_port = 8080
  force_https = true
  auto_stop_machines = 'stop'
  auto_start_machines = true
  min_machines_running = 0
  processes = ['app']

  [[http_service.checks]]
    interval = '10s'
    timeout = '2s'
    grace_period = '5s'
    method = 'GET'
    path = '/up'
    protocol = 'http'
    tls_skip_verify = false
    [http_service.checks.headers]
      X-Forwarded-Proto = 'https'

[[vm]]
  memory = '2gb'
  cpu_kind = 'shared'
  cpus = 1

Step 6: Deploy Your App

fly deploy --app your-app-test

Wait 3-5 minutes for the build and deployment to complete.

Watch logs in another terminal:

fly logs --app your-app-test

Step 7: Run Database Migrations

fly ssh console --app your-app-test -C "rails db:migrate"

Step 8: Test Your App

fly open --app your-app-test

Your app opens at: https://your-app-test.fly.dev

✅ Test Environment is Live!

Part 4: Create Admin User

Step 1: SSH into Your App

fly ssh console --app your-app-test

Step 2: Start Rails Console

./bin/rails console

Or:

bundle exec rails console

Step 3: Create Admin

Admin.create!(
  email: 'admin@example.com',
  password: 'TestPassword123!',
  password_confirmation: 'TestPassword123!'
)

Note: Replace Admin with User if your model is called User. Adjust fields based on your model.

Step 4: Verify Admin Created

Admin.last

Should show your newly created admin.

Step 5: Exit

exit  # Exit Rails console
exit  # Exit SSH

Alternative: One-Line Command

From your local terminal:

fly ssh console --app your-app-test -C "./bin/rails runner \"Admin.create!(email: 'admin@example.com', password: 'TestPassword123!', password_confirmation: 'TestPassword123!')\""

Step 6: Test Admin Login

1. Visit your app: https://your-app-test.fly.dev/admin
2. Login with credentials you just created
3. Verify everything works ✅

Part 5: Deploy to Production

Now that testing works, let's create a production environment.

Step 1: Create Production App

fly launch --no-deploy

Configuration:

• App name: your-app-prod
• Region: Same as test or closer to users
• Tweak settings: Y (Yes)

Step 2: Configure Production Settings

In the browser form:

• App name: your-app-prod
• Region: Choose production region
• Internal port: 8080
• VM Memory: 2GB (more for production)
• Postgres: none (using Supabase)
• Tigris: Disabled

Click "Confirm Settings"

Step 3: Create Production Supabase Database

Option A: Use Same Database

• Use the same Supabase database for production
• Good for small projects
• Cost: FREE

Option B: Create Separate Database (Recommended)

1. Go to Supabase dashboard
2. Create new project: your-app-prod
3. Get new DATABASE_URL
4. Keep test and production data separate ✅

Step 4: Set Production Secrets

# Generate NEW secret for production
rails secret

# Set database URL
fly secrets set DATABASE_URL="your-production-supabase-url" --app your-app-prod

# Set NEW secret key base
fly secrets set SECRET_KEY_BASE="new-secret-from-rails-secret" --app your-app-prod

# Copy AWS credentials (or use different production bucket)
fly secrets set AWS_ACCESS_KEY_ID="your-aws-key" --app your-app-prod
fly secrets set AWS_SECRET_ACCESS_KEY="your-aws-secret" --app your-app-prod
fly secrets set AWS_REGION="your-region" --app your-app-prod
fly secrets set BUCKET_NAME="your-production-bucket" --app your-app-prod
fly secrets set AWS_ENDPOINT_URL_S3="your-s3-endpoint" --app your-app-prod

# Verify
fly secrets list --app your-app-prod

Step 5: Update Production fly.toml

Open fly.toml and update:

app = 'your-app-prod'
primary_region = 'sin'

[env]
  PORT = '8080'
  RAILS_ENV = 'production'

[http_service]
  internal_port = 8080
  force_https = true
  auto_stop_machines = 'suspend'
  auto_start_machines = true
  min_machines_running = 1  # Keep 1 always running in production

[[vm]]
  memory = '2gb'
  cpu_kind = 'shared'
  cpus = 2  # More CPU for production

Step 6: Deploy Production

fly deploy --app your-app-prod

Wait for deployment to complete.

Step 7: Run Migrations

fly ssh console --app your-app-prod -C "rails db:migrate"

Step 8: Create Production Admin

fly ssh console --app your-app-prod -C "./bin/rails runner \"Admin.create!(email: 'admin@yourdomain.com', password: 'StrongProductionPassword123!', password_confirmation: 'StrongProductionPassword123!')\""

Save these credentials securely!

Step 9: Test Production App

fly open --app your-app-prod

Visit: https://your-app-prod.fly.dev

✅ Production is Live!

Part 6: Buy and Connect Domain

Step 1: Buy Domain from Namecheap

Why Namecheap?

• ✅ Cheapest overall (~$10/year)
• ✅ FREE privacy protection forever
• ✅ FREE email forwarding
• ✅ Easy DNS management
• ✅ Great support

Purchase Process:

1. Go to: https://www.namecheap.com
2. Search for your desired domain
3. Add to cart
4. At checkout:
   • ✅ Check: WhoisGuard (Privacy Protection) - FREE
   • ❌ Uncheck: PremiumDNS
   • ❌ Uncheck: Email hosting
   • ❌ Uncheck: Website builder
   • ❌ Uncheck: SSL certificate
5. Complete purchase (~$10-13)

Step 2: Get Fly.io IP Addresses

# Get your production app's IPs
fly ips list --app your-app-prod

Output shows:

VERSION  IP                      TYPE    REGION
v4       66.241.125.202         public  global
v6       2a09:8280:1::a0:a7a4:0 public  global

Copy both IPs - you'll need them next!

Step 3: Add Domain to Fly.io

# Add main domain
fly certs add yourdomain.com --app your-app-prod

# Add www subdomain
fly certs add www.yourdomain.com --app your-app-prod

Example:

fly certs add name.com --app name-website-prod
fly certs add www.noblmed.com --app name-website-prod

Step 4: Configure DNS in Namecheap

Login to Namecheap:

1. Go to: https://www.namecheap.com
2. Click "Sign In"
3. Enter credentials

Go to Domain Management:

1. Click "Domain List" (left sidebar)
2. Find your domain
3. Click "Manage" button

Open Advanced DNS:

1. Click "Advanced DNS" tab

Delete Old Records:

Look for and DELETE any existing:

• A Records with @ or blank host
• CNAME Records with @ or blank host
• Parking page records

Add New DNS Records:

Record 1 - A Record (IPv4):

Type: A Record
Host: @
Value: 66.241.125.202  (your IPv4 from Step 2)
TTL: Automatic

Click ✅ to save.

Record 2 - AAAA Record (IPv6):

Type: AAAA Record
Host: @
Value: 2a09:8280:1::a0:a7a4:0  (your IPv6 from Step 2)
TTL: Automatic

Click ✅ to save.

Record 3 - CNAME Record (WWW):

Type: CNAME Record
Host: www
Target: your-app-prod.fly.dev.  (note the dot at end!)
TTL: Automatic

Click ✅ to save.

Save All Changes:

Scroll to bottom and click "SAVE ALL CHANGES"

Step 5: Wait for DNS Propagation

Wait 10-30 minutes for DNS changes to spread worldwide.

Check DNS Status:

# Check main domain
dig yourdomain.com

# Check www subdomain
dig www.yourdomain.com

Or check online: https://www.whatsmydns.net/

Step 6: Verify SSL Certificates

After 15-20 minutes:

# Check main domain certificate
fly certs show yourdomain.com --app your-app-prod

# Check www certificate
fly certs show www.yourdomain.com --app your-app-prod

When ready, you'll see:

The certificate for yourdomain.com has been issued.
Status: Ready ✅

Step 7: Test Your Domain

Open browser and visit:

• https://yourdomain.com
• https://www.yourdomain.com

Both should:

• ✅ Load your website
• ✅ Show 🔒 padlock (secure HTTPS)
• ✅ Work perfectly!

🎉 Your Custom Domain is Live!

Part 7: Set Up Email Forwarding

Step 1: Enable Email Forwarding

In Namecheap (still on your domain's management page):

1. Look for "Mail Settings" or "Email Forwarding" section
2. Click "Add Forwarder" or "Enable Email Forwarding"

Step 2: Add Email Forwards

Create forwarding rules:

Example forwards:

How to add each:

1. Click "Add Forwarder"
2. Alias: Enter admin (without @domain)
3. Forward to: Enter your Gmail
4. Click "Add" or ✅
5. Repeat for other addresses

Step 3: Save Email Settings

Click "Save Changes"

Step 4: Test Email Forwarding

1. Send test email to: admin@yourdomain.com
2. Check your Gmail inbox
3. Should receive within 1-2 minutes ✅

Step 5: Set Up Gmail "Send As" (Optional)

To reply from admin@yourdomain.com:

1. Open Gmail
2. Click ⚙️ Settings → "See all settings"
3. Click "Accounts and Import" tab
4. Find "Send mail as:"
5. Click "Add another email address"
6. Enter:
   • Name: Your Name / Company
   • Email: admin@yourdomain.com
   • Uncheck "Treat as an alias"
7. Click "Next Step"
8. For SMTP, you need paid email service (Google Workspace, Zoho, etc.)

Note: Free forwarding only receives emails. To send, you need:

• Google Workspace ($6/month)
• Zoho Mail (free for up to 5 users)
• Or reply from your Gmail (recipient sees Gmail address)

Part 8: Managing Your App

View App Status

# Check if app is running
fly status --app your-app-prod

# List all machines
fly machine list --app your-app-prod

# View recent logs
fly logs --app your-app-prod

Stop App (When Not in Use)

To save costs when not needed:

# Stop all machines
fly scale count 0 --app your-app-prod

What happens:

• ✅ App stops completely
• ✅ No compute charges (only storage)
• ✅ Visitors see "503 Service Unavailable"
• ✅ Database and files remain safe

Start App Again

# Start 1 machine
fly scale count 1 --app your-app-prod

What happens:

• ✅ App starts in 10-30 seconds
• ✅ Website works normally
• ✅ Everything restored

Auto-Stop Configuration

Edit fly.toml to automatically stop when idle:

[http_service]
  auto_stop_machines = 'stop'      # Auto-stop when no traffic
  auto_start_machines = true       # Auto-start when visitor arrives
  min_machines_running = 0         # Allow stopping completely

Benefits:

• ✅ Automatically stops after 5 minutes of no traffic
• ✅ Automatically starts when someone visits
• ✅ Saves money on low-traffic sites
• ⚠️ First visitor waits ~10 seconds for startup

For always-on production:

[http_service]
  auto_stop_machines = false
  auto_start_machines = true
  min_machines_running = 1  # Always keep 1 running

Restart App

fly apps restart your-app-prod

View Dashboard

fly dashboard --app your-app-prod

Opens web dashboard in browser.

SSH into App

fly ssh console --app your-app-prod

Run Rails Console

fly ssh console --app your-app-prod -C "./bin/rails console"

Update App

After making code changes:

# Commit changes to git
git add .
git commit -m "Your changes"

# Deploy update
fly deploy --app your-app-prod

# Watch deployment
fly logs --app your-app-prod

Scale Resources

# Add more memory
fly scale memory 4096 --app your-app-prod

# Add more machines
fly scale count 2 --app your-app-prod

# Change VM type
fly scale vm shared-cpu-2x --app your-app-prod

View Costs

fly orgs show

Shows your current usage and estimated costs.

Troubleshooting

Issue: "Database connection failed"

Solution:

# Verify DATABASE_URL is set
fly secrets list --app your-app-prod

# Re-set if needed
fly secrets set DATABASE_URL="your-correct-url" --app your-app-prod

# Restart app
fly apps restart your-app-prod

Issue: "DNS not resolving"

Solution:

1. Check DNS records in Namecheap
2. Verify IPs match: fly ips list --app your-app-prod
3. Wait 30 more minutes for propagation
4. Clear browser cache or try incognito

Issue: "SSL certificate not issued"

Solution:

# Check certificate status
fly certs show yourdomain.com --app your-app-prod

# If stuck, remove and re-add
fly certs remove yourdomain.com --app your-app-prod
fly certs add yourdomain.com --app your-app-prod

# Wait 15 minutes

Issue: "App not starting"

Solution:

# Check logs for errors
fly logs --app your-app-prod

# Common issues:
# - Missing SECRET_KEY_BASE
# - Wrong DATABASE_URL
# - Port configuration (should be 8080)

# Verify secrets
fly secrets list --app your-app-prod

# Check fly.toml port settings
cat fly.toml | grep port

Issue: "Can't create admin"

Solution:

# SSH into app
fly ssh console --app your-app-prod

# Check your model name
./bin/rails runner "puts User.column_names"
# or
./bin/rails runner "puts Admin.column_names"

# Create with correct fields
./bin/rails console
Admin.create!(email: 'test@example.com', password: 'password123', password_confirmation: 'password123')

Issue: "File uploads not working"

Solution:

# Verify S3 credentials are set
fly secrets list --app your-app-prod

# Should see:
# - AWS_ACCESS_KEY_ID
# - AWS_SECRET_ACCESS_KEY
# - AWS_REGION
# - BUCKET_NAME
# - AWS_ENDPOINT_URL_S3

# Test S3 connection in Rails console
fly ssh console --app your-app-prod -C "./bin/rails console"
# Then test upload

Issue: "Out of memory errors"

Solution:

# Check current memory
fly status --app your-app-prod

# Increase memory
fly scale memory 4096 --app your-app-prod

# Or reduce memory if overprovisioned
fly scale memory 1024 --app your-app-prod

Issue: "Emails not forwarding"

Solution:

1. Check Namecheap email forwarding settings
2. Verify Gmail isn't marking as spam
3. Wait 30 minutes for DNS changes
4. Test with different email provider

Get Help

# Fly.io community forum
# https://community.fly.io

# Fly.io documentation
# https://fly.io/docs

# View all Fly commands
fly help

# Get help for specific command
fly help deploy

Quick Command Reference

Deployment

# Initialize app
fly launch --no-deploy

# Deploy app
fly deploy --app your-app-name

# Deploy with specific fly.toml
fly deploy --app your-app-name --config fly.toml

App Management

# View status
fly status --app your-app-name

# View logs
fly logs --app your-app-name

# Restart app
fly apps restart your-app-name

# Stop app
fly scale count 0 --app your-app-name

# Start app
fly scale count 1 --app your-app-name

# Open app in browser
fly open --app your-app-name

SSH & Console

# SSH into app
fly ssh console --app your-app-name

# Run Rails console
fly ssh console --app your-app-name -C "./bin/rails console"

# Run one-off command
fly ssh console --app your-app-name -C "rails db:migrate"

Secrets

# List secrets
fly secrets list --app your-app-name

# Set secret
fly secrets set KEY="value" --app your-app-name

# Unset secret
fly secrets unset KEY --app your-app-name

Domain & SSL

# Add domain
fly certs add yourdomain.com --app your-app-name

# Check certificate
fly certs show yourdomain.com --app your-app-name

# List all certificates
fly certs list --app your-app-name

# Remove certificate
fly certs remove yourdomain.com --app your-app-name

Scaling

# Scale number of machines
fly scale count 2 --app your-app-name

# Scale memory
fly scale memory 2048 --app your-app-name

# Change VM type
fly scale vm shared-cpu-2x --app your-app-name

Database

# Run migrations
fly ssh console --app your-app-name -C "rails db:migrate"

# Create database
fly ssh console --app your-app-name -C "rails db:create"

# Seed database
fly ssh console --app your-app-name -C "rails db:seed"

# Reset database (CAREFUL!)
fly ssh console --app your-app-name -C "rails db:reset"

Cost Breakdown

Monthly Costs

Ways to Save

1. Use auto-stop: App stops when not in use
2. Use free tier Supabase: Instead of paid Postgres
3. Share S3 bucket: Use same bucket for test/prod
4. Buy domain for multiple years: Slight discount
5. Use email forwarding: Instead of Google Workspace

Next Steps

After completing this guide, you can:

1. Add monitoring: Set up Sentry or error tracking
2. Add analytics: Google Analytics, Plausible, etc.
3. Set up CI/CD: GitHub Actions for auto-deploy
4. Add custom email: Google Workspace or Zoho
5. Scale up: Add more machines, memory, regions
6. Add CDN: Cloudflare for better performance
7. Set up backups: Automate database backups
8. Add staging: Create staging environment

Summary

You've learned how to:

✅ Install Fly CLI and set up account
✅ Create FREE Supabase database
✅ Deploy Rails app to Fly.io (test and production)
✅ Create admin users
✅ Buy and connect custom domain
✅ Set up FREE email forwarding
✅ Manage, stop, and start your app
✅ Troubleshoot common issues

Your app is now live with:

• Custom domain with SSL
• Professional email addresses
• Free database
• Scalable hosting
• All for ~$7-16/month!

Congratulations! 🎉

Support & Resources

• Fly.io Docs: https://fly.io/docs
• Fly.io Community: https://community.fly.io
• Supabase Docs: https://supabase.com/docs
• Namecheap Support: https://www.namecheap.com/support
• Rails Guides: https://guides.rubyonrails.org

Made with ❤️ for beginners

This content originally appeared on DEV Community and was authored by Quinterabok

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