Branches

A Prisma.Branch groups databases under a git-style name inside a project. Branches are how a project separates production data from previews: the default branch carries the production role, every other branch is a preview.

import * as Prisma from "alchemy/Prisma";

const branch = yield* Prisma.Branch("preview", { project });

gitName is optional — omitted, alchemy generates a stable physical name. Pass one when the branch should mirror a real git branch:

const branch = yield* Prisma.Branch("feature", {
  project,
  gitName: "feature/search",
});

Attaching databases

A database joins a branch by branchId (or branchGitName):

const previewDb = yield* Prisma.Postgres("preview-db", {
  project,
  branchId: branch.branchId,
});

Compute apps attach the same way — an app on a preview branch gets the preview environment class, so its environment variables stay separate from production’s.

A branch per stage

Branch names can come from the Stack’s stage, giving every preview stage its own branch — and the databases and apps attached to it — that tears down with the stage:

import { Stage } from "alchemy";

const stage = yield* Stage;

const branch = yield* Prisma.Branch("stage", {
  project,
  gitName: `preview/${stage}`,
});

Default-branch promotion

isDefault: true promotes the branch, atomically demoting the current default. The Management API only supports promotion — a demotion happens by promoting another branch — and alchemy records the displaced branch so destroying the resource can restore it:

const release = yield* Prisma.Branch("release", {
  project,
  gitName: "release/next",
  isDefault: true,
});

The production branch itself is owned by the project and cannot be deleted directly — delete the owning Prisma.Project instead.

Where next

• Postgres — projects and databases.
• Connections — credentials for the databases on a branch.

Reference:

• Branch API reference