Does Fastify Work With PlanetScale?
Fastify works excellently with PlanetScale—you can build fast, scalable applications by connecting Fastify to PlanetScale via the mysql2 driver or Prisma ORM.
Quick Facts
How Fastify Works With PlanetScale
Fastify pairs naturally with PlanetScale because both prioritize performance and minimal overhead. You connect to PlanetScale using the mysql2 driver (which supports TLS by default) or through ORMs like Prisma, Drizzle, or Sequelize. PlanetScale's serverless architecture means your database automatically scales with Fastify's ability to handle thousands of concurrent requests. The developer experience is smooth: PlanetScale's branching feature lets you test schema migrations in isolated branches before deploying to production, and Fastify's plugin ecosystem makes it easy to integrate database connection pooling. One architectural consideration is PlanetScale's connection limits—the free tier allows 10 concurrent connections, so you'll want to use a connection pool (mysql2/promise with pooling, or Prisma's built-in pooling) to avoid exhausting connections in high-traffic scenarios. For serverless deployments (Vercel, AWS Lambda), PlanetScale's serverless driver eliminates the traditional TCP connection overhead, making it ideal for Fastify applications that need to scale from zero.
Best Use Cases
Quick Setup
npm install fastify mysql2 dotenvimport Fastify from 'fastify';
import mysql from 'mysql2/promise';
const fastify = Fastify();
const pool = mysql.createPool({
host: process.env.PLANETSCALE_HOST,
user: process.env.PLANETSCALE_USER,
password: process.env.PLANETSCALE_PASSWORD,
database: process.env.PLANETSCALE_DB,
waitForConnections: true,
connectionLimit: 5,
queueLimit: 0,
enableKeepAlive: true,
keepAliveInitialDelayMs: 0,
});
fastify.get('/users', async (request, reply) => {
const [rows] = await pool.query('SELECT * FROM users LIMIT 10');
return rows;
});
fastify.listen({ port: 3000 }, (err) => {
if (err) throw err;
console.log('Server running on http://localhost:3000');
});Known Issues & Gotchas
Connection limits on free tier (10 concurrent connections) can cause 'too many connections' errors under load
Fix: Implement connection pooling with mysql2/promise and set appropriate pool size (5-8 connections for free tier). Monitor with PlanetScale's console metrics.
Foreign key constraints are disabled by default in PlanetScale due to online schema migration requirements
Fix: Enable foreign keys explicitly if needed, or handle referential integrity at the application layer. Check PlanetScale documentation for constraint workarounds.
Large transactions can timeout with serverless driver on Vercel/Lambda due to connection initialization overhead
Fix: Break large operations into smaller transactions or use the standard mysql2 driver with connection pooling for long-running processes.
PlanetScale connection strings expose password in plain text when configured as environment variables
Fix: Always use environment variables with proper secret management in production (GitHub Secrets, Vercel Environment Variables, etc.).
Alternatives
- •Express.js with PlanetScale (more mature ecosystem, slower request handling than Fastify)
- •Hono with PlanetScale (lightweight alternative optimized for serverless, similar performance to Fastify)
- •Nest.js with PlanetScale (full-featured framework with built-in TypeORM integration, higher overhead)
Resources
Related Compatibility Guides
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