Does Ruby on Rails Work With PlanetScale?
Rails works seamlessly with PlanetScale as a drop-in MySQL replacement with excellent developer experience.
Quick Facts
How Ruby on Rails Works With PlanetScale
Ruby on Rails integrates with PlanetScale through the standard MySQL2 adapter, requiring only a connection string change in your database.yml configuration. PlanetScale provides a MySQL 8.0-compatible wire protocol, so Rails' ActiveRecord ORM treats it identically to traditional MySQL deployments. You get all of Rails' migration tools, query builders, and ORM features out of the box with zero code changes to your application logic.
The developer experience is particularly smooth because PlanetScale's branching feature maps beautifully to Rails' development workflow. You can create database branches for feature development, run migrations on isolated branches before merging to production, and leverage PlanetScale's web console alongside Rails' built-in migration system. The serverless nature means no connection pooling overhead for small projects, though you'll want to configure connection limits appropriately for larger applications. FOREIGN KEY constraints are supported but disabled by default in PlanetScale, which aligns well with Rails' convention of handling associations at the ORM level rather than at the database level.
Best Use Cases
Rails + PlanetScale Connection Setup
bundle add mysql2# config/database.yml
default: &default
adapter: mysql2
encoding: utf8mb4
pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
socket: /tmp/mysql.sock
production:
<<: *default
database: <%= ENV["DB_NAME"] %>
username: <%= ENV["DB_USER"] %>
password: <%= ENV["DB_PASSWORD"] %>
host: <%= ENV["DB_HOST"] %>
ssl_mode: verify_identity
sslca: /etc/ssl/certs/ca-certificates.crt
# .env (PlanetScale connection string)
# DB_HOST=aws.connect.psdb.cloud
# DB_USER=your_username
# DB_PASSWORD=your_password
# DB_NAME=your_databaseKnown Issues & Gotchas
Foreign key constraints disabled by default, potentially allowing invalid data if not handled at application level
Fix: Enable foreign key support in PlanetScale settings if your Rails app expects database-level referential integrity, or rely on ActiveRecord validations
Connection limits are lower than traditional databases; connection pooling exhaustion under high concurrency
Fix: Configure connection pool size appropriately in database.yml, typically 5-10 for serverless workloads, and use PgBouncer-style connection pooling if needed
SAVEPOINT and nested transaction complexity in Rails migrations can conflict with PlanetScale's transaction model
Fix: Test migrations thoroughly in a PlanetScale development branch before production; simple migrations work fine but complex nested transactions may need refactoring
Timezone handling differences if PlanetScale instance is in different region than application servers
Fix: Configure explicit timezone in Rails config.time_zone and use CONVERT_TZ() in queries if timezone-sensitive comparisons are needed
Alternatives
- •PostgreSQL with Rails + AWS RDS (traditional managed database with more advanced features)
- •MongoDB with Rails + MongoDB Atlas (document database for flexible schema requirements)
- •Supabase (PostgreSQL alternative with built-in auth and real-time features)
Resources
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