mfe-forge dev

Start development servers for discovered apps and hosts.

Synopsis

mfe-forge dev [options]

Description

dev selects target apps, then runs the root package.json script dev:<scope>:<name> for each one. Those scripts are written by generate and delegate to the app's own dev script through the package manager's workspace filter.

• One target: <pm> run dev:<scope>:<name> runs in the foreground with inherited stdio.
• Several targets: the commands run in parallel through npx --yes concurrently --kill-others-on-fail, with output prefixed by app name.

Options

Flag	Type	Default	Description
-s, --scope <scope>	string		Run every app in the scope, plus <scope>/host if it exists.
-a, --app <app>	scope/name or bare name		Run one app. A bare name must be unambiguous across scopes.
-p, --parallel <n>	number	10	Accepted but not applied; all selected targets start at once.
--host-only	boolean	false	Run only hosts (apps/<scope>/host).
--build-watch	boolean	false	Accepted but not implemented; it has no effect.
-h, --help	boolean		Show help.

Precedence when several selectors are given: --app, then --scope, then --host-only. With none, every discovered app (hosts included) is started.

Configuration fields not used

dev.parallelLimit and dev.autoStartHost are validated but not read by dev.

Target discovery

An app is any directory apps/<scope>/<name>/ that contains vite.config.ts. A host is the app named host in a scope. Design systems and packages/* are not started.

Examples

mfe-forge dev                  # everything
mfe-forge dev --scope shop     # shop/* plus shop/host
mfe-forge dev --app cart       # only shop/cart (if "cart" is unique)
mfe-forge dev --host-only

Behavior details

• concurrently is fetched on demand with npx --yes, so the first multi-app run needs network access, and npm must be available even in Bun or pnpm projects.
• --kill-others-on-fail stops every server as soon as one exits with an error.
• If the concurrently process itself fails (including when a server crashes), the CLI falls back to starting each target sequentially in the foreground. Each sequential server blocks until it exits; an exit prints ⚠ <app> exited and moves on to the next target.
• The script name for shop/cart is dev:shop:cart. If you remove that root script, dev cannot start the app.

Workspace globs

The default scripts use <pm> --filter <package>, which only finds apps that are workspace members. The init template's apps/* glob does not match apps/<scope>/<name>; use apps/*/*. pnpm also needs a pnpm-workspace.yaml. See init.

Failure modes

Situation	Result
--app does not resolve	App "<app>" not found, exit 1.
No targets matched (empty project, empty scope, no hosts)	No apps found to run, exit 0.
The single target's script fails	Dev server failed, exit 2.
Configuration invalid	Exit 3.

Related

• generate — creates the dev:* scripts
• doctor — checks port conflicts and workspaces
• Troubleshooting