Does Ruby on Rails Work With Vercel?
Rails can run on Vercel via serverless functions, but it's not the platform's primary use case and requires significant architectural changes.
Quick Facts
How Ruby on Rails Works With Vercel
Vercel is fundamentally designed for frontend frameworks and static sites, not monolithic backend frameworks like Rails. However, you can deploy Rails API backends to Vercel using serverless functions by converting your Rails app into a handler that Vercel can invoke. This requires restructuring your application—moving away from Rails' traditional request/response cycle and instead exporting a handler function compatible with Node.js environments. You'll need to use a gem like `rails-lambda` or write custom middleware to adapt Rails to the serverless model. The Rails frontend (if using it) can be deployed separately as a static site or Next.js app. This approach works best for lightweight API backends, but you lose many Rails conveniences like background jobs, WebSockets, and file uploads without additional services.
Best Use Cases
Rails API Handler for Vercel Serverless
gem 'rails', '~> 7.0' && gem 'rack'# api/handler.rb
require_relative '../config/environment'
Rails.application.config.eager_load = true
app = Rails.application
Handler = lambda do |event:, context:|
# Convert Vercel event to Rack format
env = {
'REQUEST_METHOD' => event['httpMethod'],
'PATH_INFO' => event['path'],
'QUERY_STRING' => (event['queryStringParameters'] || {}).map { |k,v| "#{k}=#{v}" }.join('&'),
'rack.input' => StringIO.new(event['body'] || ''),
'CONTENT_TYPE' => event['headers']['content-type'] || 'application/json'
}
status, headers, body = app.call(env)
{ statusCode: status, headers: headers, body: body.join }
endKnown Issues & Gotchas
Cold starts and execution timeouts: Serverless functions have 10-60 second timeout limits, which can be problematic for long-running Rails operations
Fix: Offload heavy operations to background jobs using external services like Sidekiq Cloud or AWS SQS; optimize database queries and avoid N+1 problems
Database connection pooling breaks in serverless: Each function invocation creates new connections, exhausting database connection limits
Fix: Use a connection pooler like PgBouncer or Prisma's built-in pooling; configure Rails with a reduced database pool size
Rails asset pipeline and static file serving don't work on Vercel
Fix: Use a separate frontend (Next.js, React) or serve assets from a CDN; configure Rails as API-only
WebSockets and real-time features are unsupported in serverless functions
Fix: Use external services like Pusher, Socket.io, or AWS AppSync for real-time features
File uploads default to ephemeral /tmp storage and don't persist between invocations
Fix: Stream uploads directly to S3 or another object storage service; avoid local file system writes
Alternatives
- •Render or Railway: Traditional cloud platforms with native Rails support, persistent processes, and zero serverless friction
- •AWS Elastic Beanstalk + Next.js on Vercel: Run full Rails backend on traditional servers while hosting React frontend on Vercel
- •Fly.io + Vercel: Deploy Rails containerized apps with websocket support on Fly.io, frontend separately on Vercel
Resources
Related Compatibility Guides
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