PlanetScale

PlanetScale gives you serverless MySQL (Vitess-backed) and managed Postgres with a branch-per-PR workflow. With alchemy you declare the database, its branches, and the credentials as resources in the same Stack as your Workers — branches fork per preview stage and tear down with it.

New here? Set up credentials first.

Choose an engine

PlanetScale runs two engines, and alchemy models each as its own resource family:

• Postgres — managed PostgreSQL. PostgresDatabase, PostgresBranch, and PostgresRole (a user + password with least-privilege inherited roles).
• MySQL — Vitess-backed serverless MySQL. MySQLDatabase, MySQLBranch, and MySQLPassword (with role: "readwriter" instead of inherited roles).

Both families share the same shape — only the credential model differs.

Resources

A database owns the long-lived cluster, a branch is a cheap fork, and a role materializes a user + password. In Postgres terms:

const database = yield* Planetscale.PostgresDatabase("app-db", {
  region: { slug: "us-east" },
  clusterSize: "PS_10",
});

const branch = yield* Planetscale.PostgresBranch("app-branch", {
  database,
  isProduction: false,
});

const role = yield* Planetscale.PostgresRole("app-role", {
  database,
  branch,
  inheritedRoles: ["postgres"],
});

Every database and branch also accepts a migrationsDir of .sql files applied in order on each deploy — see Migrations for ordering, hashing, and the Drizzle pairing.

The PlanetScale path

The role’s origin output (host / port / database / user / password) feeds straight into Cloudflare Hyperdrive for edge-pooled connections:

const hyperdrive = yield* Cloudflare.Hyperdrive.Connection("app-hyperdrive", {
  origin: role.origin,
});

The guides that take this to production live under Cloudflare — each covers PlanetScale directly, Postgres and MySQL alike:

• Hyperdrive — provision the database, front it with Hyperdrive, and bind the connection into a Worker.
• Add Drizzle ORM — schema as a resource, migrations generated and applied on every deploy.
• Shared database across stages and branch from a shared database — branch-per-PR preview environments off one long-lived database.

Reference

• Postgres: PostgresDatabase · PostgresBranch · PostgresRole · PostgresDefaultRole
• MySQL: MySQLDatabase · MySQLBranch · MySQLPassword