Refactored scripts to remove any extra code from build-frontend.py and devserver.py (for better user editability). Individual helper functions can still be imported from scripts/fastapi-vue/ for any customization needs. Removed devmode support from CLI entry point simplifying it. Instead running via FastAPI CLI in dev mode (but it is still easy to modify to use a custom CLI entry).

fastapi_vue_setup.py

@@ -13,6 +13,7 @@ Options:
 import argparse
 import os
 import re
+import shutil
 import subprocess
 import sys
 from pathlib import Path
@@ -51,9 +52,7 @@ PYPROJECT_ADDITIONS = {
 # Frontend instantiation block for patching existing apps
 FRONTEND_BLOCK = """
 # Vue Frontend static files
-frontend = Frontend(
+frontend = Frontend(Path(__file__).with_name("frontend-build"), cached=["/assets/"])
-    Path(__file__).with_name("frontend-build"), spa=True, cached=["/assets/"]
-)
 """
 
 # TypeScript health check script for Vue components
@@ -138,10 +137,18 @@ def find_module_name(project_dir: Path) -> str | None:
     return None
 
 
-def find_fastapi_app(module_dir: Path) -> tuple[Path, str] | None:
+def find_fastapi_app(
+    module_dir: Path, project_dir: Path | None = None
+) -> tuple[Path, str] | None:
     """Find the FastAPI app in a module directory.
 
     Returns (file_path, app_variable_name) or None if not found.
+
+    Search order:
+    1. Common app files in module_dir (app.py, main.py, etc.)
+    2. All .py files in module_dir
+    3. Subpackage indicated by CLI entrypoint in pyproject.toml
+    4. Follow re-exports in __init__.py files
     """
     # Common app file names to check first
     candidates = ["app.py", "main.py", "server.py", "api.py", "__init__.py"]
@@ -154,13 +161,155 @@ def find_fastapi_app(module_dir: Path) -> tuple[Path, str] | None:
             if result:
                 return path, result
 
-    # Then check all .py files
+    # Then check all .py files in module_dir
     for path in module_dir.glob("*.py"):
         if path.name not in candidates:
             result = _find_app_in_file(path)
             if result:
                 return path, result
 
+    # Try to find app via CLI entrypoint in pyproject.toml
+    if project_dir:
+        result = _find_app_via_entrypoint(module_dir, project_dir)
+        if result:
+            return result
+
+    return None
+
+
+def _find_app_via_entrypoint(
+    module_dir: Path, project_dir: Path
+) -> tuple[Path, str] | None:
+    """Find FastAPI app by following the CLI entrypoint in pyproject.toml.
+
+    If pyproject.toml has a script like `myapp = "myapp.subpkg.__main__:main"`,
+    look in myapp/subpkg/ for the app (checking __init__.py exports and common files).
+    """
+    pyproject = project_dir / "pyproject.toml"
+    if not pyproject.exists():
+        return None
+
+    try:
+        data = tomlkit.parse(pyproject.read_text())
+    except Exception:
+        return None
+
+    scripts = data.get("project", {}).get("scripts", {})
+    if not scripts:
+        return None
+
+    module_name = module_dir.name
+
+    # Find script entries that reference this module
+    for script_name, entry in scripts.items():
+        if not isinstance(entry, str):
+            continue
+        # Parse entry like "module.subpkg.__main__:main"
+        if ":" not in entry:
+            continue
+        module_path, _ = entry.rsplit(":", 1)
+        parts = module_path.split(".")
+
+        # Check if this entry starts with our module
+        if not parts or parts[0] != module_name:
+            continue
+
+        # If there's a subpackage (e.g., module.fastapi.__main__), check there
+        if len(parts) >= 2:
+            # Build path to subpackage (exclude __main__ or similar)
+            subpkg_parts = [p for p in parts[1:] if not p.startswith("_")]
+            if subpkg_parts:
+                subpkg_dir = module_dir / "/".join(subpkg_parts)
+                if subpkg_dir.is_dir():
+                    result = _find_app_in_subpackage(subpkg_dir)
+                    if result:
+                        return result
+
+    return None
+
+
+def _find_app_in_subpackage(subpkg_dir: Path) -> tuple[Path, str] | None:
+    """Find FastAPI app in a subpackage, following __init__.py exports."""
+    # First check __init__.py for re-exports like `from .mainapp import app`
+    init_file = subpkg_dir / "__init__.py"
+    if init_file.exists():
+        result = _follow_init_reexport(init_file, subpkg_dir)
+        if result:
+            return result
+
+    # Check common app file names in subpackage
+    for name in ["app.py", "main.py", "mainapp.py", "server.py", "api.py"]:
+        path = subpkg_dir / name
+        if path.exists():
+            result = _find_app_in_file(path)
+            if result:
+                return path, result
+
+    return None
+
+
+def _find_existing_cli_entrypoint(project_dir: Path, module_name: str) -> str | None:
+    """Check if pyproject.toml already has a CLI entrypoint for this module.
+
+    Returns the entrypoint string if found, None otherwise.
+    """
+    pyproject = project_dir / "pyproject.toml"
+    if not pyproject.exists():
+        return None
+
+    try:
+        data = tomlkit.parse(pyproject.read_text())
+    except Exception:
+        return None
+
+    scripts = data.get("project", {}).get("scripts", {})
+    if not scripts:
+        return None
+
+    # Look for any script that references our module
+    for script_name, entry in scripts.items():
+        if isinstance(entry, str) and entry.startswith(f"{module_name}."):
+            return f'{script_name} = "{entry}"'
+
+    return None
+
+
+def _follow_init_reexport(init_file: Path, subpkg_dir: Path) -> tuple[Path, str] | None:
+    """Follow a re-export in __init__.py to find the actual app file.
+
+    Looks for patterns like:
+    - from .mainapp import app
+    - from module.subpkg.mainapp import app
+    """
+    try:
+        content = init_file.read_text()
+    except Exception:
+        return None
+
+    # Look for: from .module import app (or similar variable names)
+    # Pattern matches: from .mainapp import app, application, etc.
+    pattern = r"from\s+\.(\w+)\s+import\s+(\w+)"
+    for match in re.finditer(pattern, content):
+        module_name, var_name = match.groups()
+        if var_name.lower() in ("app", "application", "api"):
+            target_file = subpkg_dir / f"{module_name}.py"
+            if target_file.exists():
+                # Verify the app is actually there
+                app_var = _find_app_in_file(target_file)
+                if app_var:
+                    return target_file, app_var
+
+    # Also check for absolute imports: from pkg.subpkg.module import app
+    abs_pattern = r"from\s+[\w.]+\.(\w+)\s+import\s+(\w+)"
+    for match in re.finditer(abs_pattern, content):
+        module_name, var_name = match.groups()
+        if var_name.lower() in ("app", "application", "api"):
+            target_file = subpkg_dir / f"{module_name}.py"
+            if target_file.exists():
+                app_var = _find_app_in_file(target_file)
+                if app_var:
+                    return target_file, app_var
+
     return None
 
 
@@ -242,31 +391,20 @@ def patch_app_file(
 
     # Append route at end
     lines.append("")
+    lines.append("# Serve the Vue frontend (needs to be last if SPA catch-all is used)")
     lines.append(route_line)
     content = "\n".join(lines)
 
-    # Try to patch lifespan function
+    # Try to patch lifespan function - insert await frontend.load() before yield
     lifespan_patched = False
 
-    # Look for async def lifespan pattern and insert after the opening (and docstring if present)
+    # Look for yield inside an async def lifespan function
-    lifespan_pattern = r"(async\s+def\s+lifespan\s*\([^)]*\)\s*(?:->.*?)?:\s*\n)"
+    # Find the yield statement and insert before it
-    match = re.search(lifespan_pattern, content)
+    yield_pattern = r"^([ \t]+)(yield\b)"
-    if match:
+    yield_match = re.search(yield_pattern, content, re.MULTILINE)
-        insert_pos = match.end()
+    if yield_match:
-        rest = content[insert_pos:]
+        indent = yield_match.group(1)
-
+        insert_pos = yield_match.start()
-        # Detect indentation from the next line
-        indent_match = re.match(r"([ \t]*)", rest)
-        indent = (
-            indent_match.group(1) if indent_match and indent_match.group(1) else "    "
-        )
-
-        # Check if there's a docstring and skip past it
-        docstring_pattern = r'^([ \t]*)("""[\s\S]*?"""|\'\'\'\'[\s\S]*?\'\'\')\s*\n'
-        docstring_match = re.match(docstring_pattern, rest)
-        if docstring_match:
-            insert_pos += docstring_match.end()
-
         load_code = f"{indent}await frontend.load()\n"
         content = content[:insert_pos] + load_code + content[insert_pos:]
         lifespan_patched = True
@@ -486,11 +624,14 @@ def write_file(
     dry_run: bool = False,
     executable: bool = False,
     fallback_path: Path | None = None,
+    force: bool = False,
 ) -> bool:
     """Write content to a file, handling existing files and dry-run.
 
     If fallback_path is provided and the file exists without the upgrade marker,
     the content will be written to fallback_path instead of being skipped.
+
+    If force=True, always overwrite without checking for upgrade marker.
     """
     exists = path.exists()
     if exists and not overwrite:
@@ -504,8 +645,8 @@ def write_file(
             print(f"✔️  {path} (already up to date)")
             return False
 
-        # If overwrite requested but file doesn't have upgrade marker
+        # If overwrite requested but file doesn't have upgrade marker (unless force)
-        if overwrite and UPGRADE_MARKER not in existing_content:
+        if overwrite and not force and UPGRADE_MARKER not in existing_content:
             if fallback_path is not None:
                 # Write to fallback path instead
                 return _write_fallback_file(
@@ -580,6 +721,20 @@ def merge_pyproject(
     if "project" not in data:
         data["project"] = tomlkit.table()
 
+    # Ensure Python version is at least 3.11 (required by fastapi-vue)
+    if "requires-python" in data["project"]:
+        req = data["project"]["requires-python"]
+        # Parse minimum version from strings like ">=3.10" or ">=3.9,<4"
+        import re
+
+        match = re.search(r">=\s*(\d+)\.(\d+)", req)
+        if match:
+            major, minor = int(match.group(1)), int(match.group(2))
+            if major < 3 or (major == 3 and minor < 11):
+                data["project"]["requires-python"] = ">=3.11"
+    else:
+        data["project"]["requires-python"] = ">=3.11"
+
     # Add hatch build config
     if "tool" not in data:
         data["tool"] = tomlkit.table()
@@ -635,8 +790,6 @@ def find_js_runtime() -> tuple[str, str] | None:
     Returns (tool_path, tool_name) where tool_name is "deno", "npm", or "bun".
     Returns None if no runtime is found.
     """
-    import shutil
-
     options = ["deno", "npm", "bun"]
 
     # Check for JS_RUNTIME environment variable
@@ -798,7 +951,9 @@ def cmd_setup(args: argparse.Namespace) -> int:
     fastapi_vue_scripts = scripts_dir / "fastapi-vue"
 
     # Find existing FastAPI app
-    app_info = find_fastapi_app(module_dir) if module_dir.exists() else None
+    app_info = (
+        find_fastapi_app(module_dir, project_dir) if module_dir.exists() else None
+    )
 
     if app_info:
         app_file, app_var = app_info
@@ -814,30 +969,37 @@ def cmd_setup(args: argparse.Namespace) -> int:
 
     # Create directories
     if not dry_run:
-        fastapi_vue_scripts.mkdir(parents=True, exist_ok=True)
         if not module_dir.exists():
             module_dir.mkdir(parents=True)
+        fastapi_vue_scripts.mkdir(parents=True, exist_ok=True)
 
     # === Install scripts (always update our own scripts) ===
-    # util.py and build-frontend.py are internal and always overwritten
+    # Scripts in fastapi-vue folder are internal and always overwritten
     # devserver.py can be customized, so use fallback if needed
-    internal_script_files = [
-        (fastapi_vue_scripts / "util.py", "scripts/fastapi-vue/util.py"),
-        (
-            fastapi_vue_scripts / "build-frontend.py",
-            "scripts/fastapi-vue/build-frontend.py",
-        ),
-    ]
 
-    for dest_path, template_path in internal_script_files:
+    # Remove obsolete util.py if present
-        template = load_template(template_path)
+    obsolete_util = fastapi_vue_scripts / "util.py"
-        content = render_template(template, **tpl_vars)
+    if obsolete_util.exists():
-        write_file(
+        if dry_run:
-            dest_path,
+            print(f"[DRY RUN] Would remove obsolete {obsolete_util}")
-            content,
+        else:
-            overwrite=True,
+            obsolete_util.unlink()
-            dry_run=dry_run,
+            print(f"🗑️  Removed obsolete {obsolete_util}")
-        )
+
+    # Copy all files from the template's fastapi-vue folder
+    template_fastapi_vue_dir = TEMPLATE_DIR / "scripts" / "fastapi-vue"
+    for template_file in template_fastapi_vue_dir.iterdir():
+        if template_file.is_file():
+            dest_path = fastapi_vue_scripts / template_file.name
+            template = template_file.read_text()
+            content = render_template(template, **tpl_vars)
+            write_file(
+                dest_path,
+                content,
+                overwrite=True,
+                dry_run=dry_run,
+                force=True,  # Internal files, always overwrite
+            )
 
     # devserver.py - use fallback if customized by user
     devserver_path = scripts_dir / "devserver.py"
@@ -878,17 +1040,27 @@ def cmd_setup(args: argparse.Namespace) -> int:
     template = load_template("backend/__main__.py")
     main_content = render_template(template, **tpl_vars)
 
-    # Use write_file with fallback - it handles all cases:
+    # Check if project already has a CLI entrypoint in pyproject.toml
-    # - File doesn't exist: create it
+    existing_cli = _find_existing_cli_entrypoint(project_dir, module_name)
-    # - File exists with marker: update it
+
-    # - File exists without marker: write to fallback
+    if main_file.exists():
-    write_file(
+        # File exists: update if it has the auto-upgrade marker, otherwise use fallback
-        main_file,
+        write_file(
-        main_content,
+            main_file,
-        overwrite=True,
+            main_content,
-        dry_run=dry_run,
+            overwrite=True,
-        fallback_path=main_fallback,
+            dry_run=dry_run,
-    )
+            fallback_path=main_fallback,
+        )
+    elif not existing_cli:
+        # No file and no existing entrypoint: create new __main__.py
+        write_file(
+            main_file,
+            main_content,
+            overwrite=False,
+            dry_run=dry_run,
+        )
+    # else: no file but has existing entrypoint - don't create (user has custom CLI setup)
 
     # === Update vite.config.js/ts ===
     frontend_dir = project_dir / "frontend"
@@ -962,18 +1134,20 @@ def cmd_setup(args: argparse.Namespace) -> int:
 
     # === Update .gitignore ===
     gitignore_path = project_dir / ".gitignore"
-    gitignore_entry = f"{module_name}/frontend-build/"
+    gitignore_entry = f"/{module_name}/frontend-build"
     if gitignore_path.exists():
-        gitignore_content = gitignore_path.read_text()
+        gitignore_content = gitignore_path.read_bytes()
-        if gitignore_entry not in gitignore_content:
+        if b"frontend-build" in gitignore_content:
-            if dry_run:
+            print("✔️  .gitignore (frontend-build already ignored)")
-                print(f"[DRY RUN] Would add {gitignore_entry} to .gitignore")
+        elif dry_run:
-            else:
+            print(f"[DRY RUN] Would add {gitignore_entry} to .gitignore")
-                with open(gitignore_path, "a") as f:
+        else:
-                    if not gitignore_content.endswith("\n"):
+            nl = b"\r\n" if b"\r\n" in gitignore_content else b"\n"
-                        f.write("\n")
+            suffix = b"" if gitignore_content.endswith(nl) else nl
-                    f.write(f"{gitignore_entry}\n")
+            gitignore_path.write_bytes(
-                print(f"✅ Added {gitignore_entry} to .gitignore")
+                gitignore_content + suffix + gitignore_entry.encode() + nl
+            )
+            print(f"✅ Added {gitignore_entry} to .gitignore")
     elif dry_run:
         print(f"[DRY RUN] Would create .gitignore with {gitignore_entry}")
     else:

template/backend/__main__.py

@@ -3,35 +3,24 @@ import argparse
 import asyncio
 import os
 
-import uvicorn
 from fastapi_vue.hostutil import parse_endpoint
 from uvicorn import Config, Server
 
-from .APP_MODULE import APP_VAR
-
 DEFAULT_PORT = 5080
 
 
-def run_server(endpoints: list[dict], *, proxy="", devmode=False):
+def run_server(endpoints: list[dict], *, proxy=""):
     conf: dict[str, object] = {"app": "MODULE_NAME.APP_MODULE:APP_VAR"}
     if proxy:
         conf["proxy_headers"] = True
         conf["forwarded_allow_ips"] = proxy
-    if devmode:
-        conf["reload"] = True
-        conf["reload_dirs"] = ["MODULE_NAME"]
-        APP_VAR.debug = True
 
-    if len(endpoints) > 1:
+    async def serve_all():
-        # Run separate servers for multiple endpoints
+        async with asyncio.TaskGroup() as tg:
-        async def serve_all():
+            for ep in endpoints:
-            async with asyncio.TaskGroup() as tg:
+                tg.create_task(Server(Config(**conf, **ep)).serve())
-                for ep in endpoints:
-                    tg.create_task(Server(Config(**conf, **ep)).serve())
 
-        asyncio.run(serve_all())
+    asyncio.run(serve_all())
-    else:
-        uvicorn.run(**conf, **endpoints[0])
 
 
 def main():
@@ -46,9 +35,10 @@ def main():
     )
     args = parser.parse_args()
     proxy = os.getenv("FORWARDED_ALLOW_IPS", "127.0.0.1,::1")
-    devmode = bool(os.getenv("FASTAPI_VUE_FRONTEND_URL"))
+    try:
-    endpoints = parse_endpoint(args.endpoint, DEFAULT_PORT)
+        run_server(parse_endpoint(args.endpoint, DEFAULT_PORT), proxy=proxy)
-    run_server(endpoints, proxy=proxy, devmode=devmode)
+    except KeyboardInterrupt:
+        pass
 
 
 if __name__ == "__main__":

template/backend/app.py

@@ -5,9 +5,7 @@ from fastapi import FastAPI
 from fastapi_vue import Frontend
 
 # Vue Frontend static files
-frontend = Frontend(
+frontend = Frontend(Path(__file__).with_name("frontend-build"), cached=["/assets/"])
-    Path(__file__).with_name("frontend-build"), spa=True, cached=["/assets/"]
-)
 
 
 @asynccontextmanager
@@ -29,5 +27,5 @@ async def health_check():
     return {"status": "ok"}
 
 
-# Final catch-all route for frontend files (keep at end of file)
+# Serve the Vue frontend (needs to be last if SPA catch-all is used)
 frontend.route(app, "/")

template/scripts/devserver.py

@@ -1,242 +1,64 @@
 #!/usr/bin/env -S uv run
 # auto-upgrade@fastapi-vue-setup - remove this if you modify this file
-"""Run Vite development server for frontend and FastAPI backend with auto-reload.
+"""Run Vite development server for frontend and FastAPI backend with auto-reload."""
-
-Usage:
-    uv run scripts/devserver.py [host:port] [--backend host:port]
-
-The optional host:port argument sets where the Vite frontend listens.
-Supported forms: host[:port], :port (all interfaces), or just port.
-The --backend option sets where the FastAPI backend listens (default: localhost:5180).
-
-Environment:
-    JS_RUNTIME          Path or name of JS runtime to use (deno, npm/node or bun).
-    FASTAPI_VUE_FRONTEND_URL    Set by this script for the backend to know where Vite is.
-"""
 
 import argparse
 import asyncio
 import contextlib
 import os
+import sys
 from pathlib import Path
-from sys import stderr
 
-import httpx
+# Import util.py from scripts/fastapi-vue (not a package, so we adjust sys.path)
-from fastapi_vue.hostutil import parse_endpoint
+sys.path.insert(0, str(Path(__file__).with_name("fastapi-vue")))
-
+from devutil import (  # type: ignore
-exec((Path(__file__).parent / "fastapi-vue/util.py").read_text("UTF-8"))  # noqa: S102
+    ProcessGroup,
-
+    logger,
-DEFAULT_VITE_PORT = 5173
+    ready,
-DEFAULT_BACKEND_PORT = 5180
+    setup_fastapi,
-FRONTEND_PATH = Path(__file__).parent.parent / "frontend"
+    setup_vite,
-
+)
-EPILOG = """
-  scripts/devserver.py                       # Default ports on localhost
-  scripts/devserver.py 3000                  # Vite on localhost:3000
-  scripts/devserver.py :3000 --backend 8000  # *:3000, localhost:8000
-"""
-
-BUN_BUG = """\
-┃ ⚠️  Bun cannot correctly proxy API requests to the backend.
-┃ Bug report: https://github.com/oven-sh/bun/issues/9882
-┃
-┃ Consider using deno or npm instead for development.
-"""
 
 
-def resolve_frontend_tools(
+async def run_devserver(frontend: str, backend: str) -> None:
-    vite_port: int, all_ifaces: bool
+    reporoot = Path(__file__).parent.parent
-) -> tuple[list[str], list[str], str]:
+    front = reporoot / "frontend"
-    """Resolve frontend install and dev commands.
+    if not (front / "package.json").exists():
-
+        logger.warning("Frontend source not found at %s", front)
-    Returns (install_cmd, dev_cmd, tool_name).
-    Raises SystemExit if tools are not available.
-    """
-    if not (FRONTEND_PATH / "package.json").exists():
-        stderr.write(f"┃ ⚠️  Frontend source not found at {FRONTEND_PATH}\n")
         raise SystemExit(1)
 
-    result = find_js_runtime()  # noqa # type: ignore
+    frontend_url, npm_install, vite = setup_vite(frontend)
-    if result is None:
+    backend_url, fastapi = setup_fastapi(backend, "MODULE_NAME.APP_MODULE:APP_VAR")
-        if not os.environ.get("JS_RUNTIME"):
-            stderr.write("┃ ⚠️  deno, npm or bun needed to run the frontend server.\n")
-        raise SystemExit(1)
 
-    tool, name = result
+    # Tell the everyone where the frontend and backend are (vite proxy, etc)
+    os.environ["FASTAPI_VUE_FRONTEND_URL"] = frontend_url
+    os.environ["FASTAPI_VUE_BACKEND_URL"] = backend_url
 
-    install_args = {
+    async with ProcessGroup() as pg:
-        "deno": ("install", "--quiet", "--allow-scripts=npm:vue-demi"),
+        install_proc = await pg.spawn(*npm_install, cwd=front)
-        "npm": ("install", "--silent"),
+        await asyncio.sleep(0.2)  # reduce message overlap
-        "bun": ("install", "--silent"),
+        await pg.spawn(
-    }
+            *fastapi,
-    dev_args = {
+            "--reload",
-        "deno": ("run", "dev", "--"),
+            "--reload-dir=MODULE_NAME",  # Don't reload on frontend changes
-        "npm": ("--silent", "run", "dev", "--"),
+            "--forwarded-allow-ips=*",
-        "bun": ("run", "dev", "--"),
+            cwd=reporoot,
-    }
-
-    install_cmd = [tool, *install_args[name]]
-    dev_cmd = [
-        tool,
-        *dev_args[name],
-        "--clearScreen=false",
-        f"--port={vite_port}",
-    ]
-
-    if all_ifaces:
-        dev_cmd.append("--host")
-
-    if name == "bun":
-        stderr.write(BUN_BUG)
-
-    return install_cmd, dev_cmd, name
-
-
-async def wait_for_backend(host: str, port: int):
-    """Wait for the backend to be ready by polling the health endpoint."""
-    max_attempts = 50
-    url = f"http://{host}:{port}"
-
-    async with httpx.AsyncClient() as client:
-        for attempt in range(max_attempts):
-            try:
-                await client.get(url, timeout=1.0)
-                stderr.write("✓ Backend ready!\n")
-                return True
-            except httpx.RequestError:
-                if attempt == max_attempts - 1:
-                    stderr.write("┃ ⚠️  Backend didn't start in time\n")
-                    return False
-                await asyncio.sleep(0.1)
-    return False
-
-
-async def _terminate_process(proc: asyncio.subprocess.Process, name: str) -> None:
-    """Gracefully terminate a subprocess."""
-    if proc.returncode is not None:
-        return
-    try:
-        proc.terminate()
-    except ProcessLookupError:
-        return
-    try:
-        await asyncio.wait_for(proc.wait(), timeout=2)
-    except TimeoutError:
-        try:
-            proc.kill()
-        except ProcessLookupError:
-            return
-        await proc.wait()
-
-
-async def run_devserver(
-    vite_port: int,
-    all_ifaces: bool,
-    backend_host: str,
-    backend_port: int,
-) -> None:
-    """Run the development server with install, backend, and frontend."""
-    install_cmd, dev_cmd, tool_name = resolve_frontend_tools(vite_port, all_ifaces)
-
-    # Tell the backend where the Vite dev server is
-    os.environ["FASTAPI_VUE_FRONTEND_URL"] = f"http://localhost:{vite_port}"
-    # Tell Vite where the backend is (for proxying /api requests)
-    os.environ["FASTAPI_VUE_BACKEND_URL"] = f"http://{backend_host}:{backend_port}"
-
-    backend_cmd = [
-        "uvicorn",
-        "MODULE_NAME.app:app",
-        "--host",
-        backend_host,
-        "--port",
-        str(backend_port),
-        "--reload",
-    ]
-
-    cwd = str(Path(__file__).parent.parent)
-    frontend_cwd = str(FRONTEND_PATH)
-
-    backend_proc: asyncio.subprocess.Process | None = None
-    install_proc: asyncio.subprocess.Process | None = None
-    frontend_proc: asyncio.subprocess.Process | None = None
-
-    try:
-        # Start install (concurrent with backend)
-        stderr.write(f">>> {tool_name} {' '.join(install_cmd[1:])}\n")
-        install_proc = await asyncio.create_subprocess_exec(
-            *install_cmd, cwd=frontend_cwd
         )
 
-        await asyncio.sleep(0.1)
+        # Wait for both install and backend to be ready
+        async with asyncio.TaskGroup() as tg:
+            tg.create_task(pg.wait(install_proc))
+            tg.create_task(ready(backend_url, path="/api/health?from=devserver.py"))
 
-        # Start backend (concurrent with install)
+        # Start Vite dev server (ProcessGroup waits for any exit, then terminates others)
-        stderr.write(f">>> {' '.join(backend_cmd)}\n")
+        await pg.spawn(*vite, cwd=front)
-        backend_proc = await asyncio.create_subprocess_exec(*backend_cmd, cwd=cwd)
-
-        # Wait for install to complete and backend to be ready
-        install_task = asyncio.create_task(install_proc.wait(), name="install")
-        backend_ready_task = asyncio.create_task(
-            wait_for_backend(backend_host, backend_port), name="backend_ready"
-        )
-
-        done, pending = await asyncio.wait(
-            {install_task, backend_ready_task},
-            return_when=asyncio.FIRST_COMPLETED,
-        )
-
-        for task in done:
-            if task.get_name() == "install":
-                if task.result() != 0:
-                    stderr.write("┃ ⚠️  Install failed\n")
-                    raise SystemExit(1)
-            elif task.get_name() == "backend_ready" and not task.result():
-                raise SystemExit(1)
-
-        if pending:
-            done2, _ = await asyncio.wait(pending)
-            for task in done2:
-                if task.get_name() == "install":
-                    if task.result() != 0:
-                        stderr.write("┃ ⚠️  Install failed\n")
-                        raise SystemExit(1)
-                elif task.get_name() == "backend_ready" and not task.result():
-                    raise SystemExit(1)
-
-        install_proc = None
-
-        # Start Vite dev server
-        stderr.write(f">>> {tool_name} {' '.join(dev_cmd[1:])}\n")
-        frontend_proc = await asyncio.create_subprocess_exec(*dev_cmd, cwd=frontend_cwd)
-
-        # Wait for either process to exit
-        done, pending = await asyncio.wait(
-            {
-                asyncio.create_task(backend_proc.wait(), name="backend"),
-                asyncio.create_task(frontend_proc.wait(), name="frontend"),
-            },
-            return_when=asyncio.FIRST_COMPLETED,
-        )
-        for t in done:
-            t.result()
-        for t in pending:
-            t.cancel()
-
-    except asyncio.CancelledError:
-        stderr.write("\n✓ Shutting down...\n")
-    finally:
-        if frontend_proc is not None:
-            await _terminate_process(frontend_proc, "frontend")
-        if install_proc is not None:
-            await _terminate_process(install_proc, "install")
-        if backend_proc is not None:
-            await _terminate_process(backend_proc, "backend")
 
 
 def main():
     parser = argparse.ArgumentParser(
         description="Run Vite and FastAPI development servers",
         formatter_class=argparse.RawDescriptionHelpFormatter,
-        epilog=EPILOG,
+        epilog=HELP_EPILOG,
     )
     parser.add_argument(
         "frontend",
@@ -250,27 +72,17 @@ def main():
         help="FastAPI backend endpoint (default: localhost:5180)",
     )
     args = parser.parse_args()
-
-    # parse_endpoint returns list of dicts with host/port or uds keys
-    # Multiple entries means bind all interfaces (IPv4 + IPv6)
-    vite_endpoints = parse_endpoint(args.frontend, DEFAULT_VITE_PORT)
-    backend_endpoints = parse_endpoint(args.backend, DEFAULT_BACKEND_PORT)
-
-    # Vite doesn't support unix sockets
-    if "uds" in vite_endpoints[0]:
-        stderr.write("┃ ⚠️  Unix sockets not supported for frontend\n")
-        raise SystemExit(1)
-    if "uds" in backend_endpoints[0]:
-        stderr.write("┃ ⚠️  Unix sockets not supported for backend\n")
-        raise SystemExit(1)
-
-    vite_port = vite_endpoints[0]["port"]
-    all_ifaces = len(vite_endpoints) > 1
-    backend_host = backend_endpoints[0]["host"]
-    backend_port = backend_endpoints[0]["port"]
-
     with contextlib.suppress(KeyboardInterrupt):
-        asyncio.run(run_devserver(vite_port, all_ifaces, backend_host, backend_port))
+        asyncio.run(run_devserver(args.frontend, args.backend))
+
+
+HELP_EPILOG = """
+  scripts/devserver.py                       # Default ports on localhost
+  scripts/devserver.py 3000                  # Vite on localhost:3000
+  scripts/devserver.py :3000 --backend 8000  # *:3000, localhost:8000
+
+  JS_RUNTIME environment variable can be used to select the JS runtime
+"""
 
 
 if __name__ == "__main__":

template/scripts/fastapi-vue/build-frontend.py

@@ -1,34 +1,15 @@
 """Hatch build hook for building Vue frontend during package build."""
 
-import subprocess
+import sys
 from pathlib import Path
-from sys import stderr
 
 from hatchling.builders.hooks.plugin.interface import BuildHookInterface  # type: ignore
 
-exec(Path(__file__).with_name("util.py").read_text("UTF-8"))  # noqa: S102
+sys.path.insert(0, str(Path(__file__).parent))
-
+from buildutil import build
-
-def run(cmd, **kwargs):
-    """Run a command and display it."""
-    display_cmd = [Path(cmd[0]).name, *cmd[1:]]
-    stderr.write(f"### {' '.join(display_cmd)}\n")
-    subprocess.run(cmd, check=True, **kwargs)
 
 
 class CustomBuildHook(BuildHookInterface):
-    """Build hook that compiles Vue frontend before packaging."""
-
     def initialize(self, version, build_data):
         super().initialize(version, build_data)
-        stderr.write(">>> Building the frontend\n")
+        build("frontend")
-
-        install_cmd, build_cmd = find_build_tool()  # noqa # type: ignore
-
-        try:
-            run(install_cmd, cwd="frontend")
-            stderr.write("\n")
-            run(build_cmd, cwd="frontend")
-        except Exception as e:
-            stderr.write(f"Error occurred while building frontend: {e}\n")
-            raise

template/scripts/fastapi-vue/util.py

@@ -1,87 +0,0 @@
-"""Shared utilities for build and dev scripts."""
-
-import os
-import shutil
-from pathlib import Path
-from sys import stderr
-
-
-def find_js_runtime() -> tuple[str, str] | None:
-    """Find a JavaScript runtime from JS_RUNTIME env or auto-detect.
-
-    Returns (tool_path, tool_name) where tool_name is "deno", "npm", or "bun".
-    Returns None if no runtime is found.
-    """
-    options = ["deno", "npm", "bun"]
-
-    # Check for JS_RUNTIME environment variable
-    if js_runtime_env := os.environ.get("JS_RUNTIME"):
-        js_runtime = js_runtime_env
-        js_path = Path(js_runtime)
-        runtime_name = js_path.name
-        # Map node to npm
-        if runtime_name == "node":
-            runtime_name = "npm"
-            js_runtime = str(js_path.parent / "npm") if js_path.parent.name else "npm"
-        for option in options:
-            if option == runtime_name or runtime_name.startswith(option):
-                tool = shutil.which(js_runtime)
-                if tool is None:
-                    stderr.write(f"┃ ⚠️  JS_RUNTIME={js_runtime_env} not found\n")
-                    return None
-                return tool, option
-        stderr.write(f"┃ ⚠️  JS_RUNTIME={js_runtime_env} not recognized\n")
-        return None
-
-    # Auto-detect
-    for option in options:
-        if tool := shutil.which(option):
-            return tool, option
-    return None
-
-
-def find_build_tool():
-    """Find JavaScript runtime and construct install/build commands.
-
-    Returns (install_cmd, build_cmd) tuples of command lists.
-    Raises RuntimeError if no runtime is found.
-    """
-    install = {
-        "deno": ("install", "--allow-scripts=npm:vue-demi"),
-        "npm": ("install",),
-        "bun": ("--bun", "install"),
-    }
-    # Run vite directly for deno to avoid npm-run-all2/run-p issues
-    build = {
-        "deno": ("run", "-A", "npm:vite", "build"),
-        "npm": ("run", "build"),
-        "bun": ("--bun", "run", "build"),
-    }
-
-    result = find_js_runtime()
-    if result is None:
-        raise RuntimeError(
-            "Deno, npm or Bun is required for building but none was found"
-        )
-
-    tool, name = result
-    return [tool, *install[name]], [tool, *build[name]]
-
-
-def find_dev_tool():
-    """Find JavaScript runtime and construct dev command.
-
-    Returns (dev_cmd, tool_name) or (None, None) if not found.
-    """
-    dev_args = {
-        "deno": ("run", "dev", "--"),
-        "npm": ("--silent", "run", "dev", "--"),
-        "bun": ("run", "dev", "--"),
-    }
-
-    result = find_js_runtime()
-    if result is None:
-        return None, None
-
-    tool, name = result
-    return [tool, *dev_args[name]], name