Add --version

.gitignore

@@ -3,3 +3,4 @@
 *.lock
 __pycache__/
 dist/
+/_version.py

fastapi_vue_setup.py

@@ -15,18 +15,20 @@ import os
 import re
 import subprocess
 import sys
+import tomllib
 from pathlib import Path
 from textwrap import indent
 
-import tomlkit
+import tomli_w
+
+try:
+    from _version import __version__
+except ImportError:
+    __version__ = "0.0.0+unknown"
 
 # Template directory
 TEMPLATE_DIR = Path(__file__).parent / "template"
 
-# Marker comment indicating file can be auto-upgraded
-# Users should remove this line to prevent automatic updates
-UPGRADE_MARKER = "auto-upgrade@fastapi-vue-setup"
-
 # pyproject.toml additions for patched projects
 PYPROJECT_ADDITIONS = {
     "tool": {
@@ -129,7 +131,8 @@ def find_module_name(project_dir: Path) -> str | None:
     if not pyproject.exists():
         return None
 
-    data = tomlkit.parse(pyproject.read_text())
+    with open(pyproject, "rb") as f:
+        data = tomllib.load(f)
 
     if "project" in data and "name" in data["project"]:
         name = data["project"]["name"]
@@ -202,15 +205,19 @@ def patch_app_file(
         print(f"❌ Cannot patch {path} - file not found")
         return False
 
-    original_content = path.read_text()
+    content = path.read_text()
     marker = "from fastapi_vue import Frontend"
 
-    if marker in original_content:
+    if marker in content:
-        print(f"✔️  {path} (already patched)")
+        print(f"⚠️  Skipping {path} (already patched)")
         return False
 
+    if dry_run:
+        print(f"[DRY RUN] Would patch {path}")
+        return True
+
     # Find where to insert the import (after other imports)
-    lines = original_content.split("\n")
+    lines = content.split("\n")
     import_line = "from fastapi_vue import Frontend"
 
     route_line = f'frontend.route({app_var}, "/")'
@@ -228,11 +235,6 @@ def patch_app_file(
             # Stop at first non-import, non-comment, non-empty line after imports
             break
 
-    # Check if we found imports to insert after
-    if last_import_idx == 0 and not lines[0].strip().startswith(("import ", "from ")):
-        print(f"⚠️  Skipping {path} (no imports found to patch)")
-        return False
-
     # Insert imports after last import, then frontend instantiation
     if not has_pathlib:
         lines.insert(last_import_idx + 1, "from pathlib import Path")
@@ -271,15 +273,6 @@ def patch_app_file(
         content = content[:insert_pos] + load_code + content[insert_pos:]
         lifespan_patched = True
 
-    # Check if content actually changed
-    if content == original_content:
-        print(f"⚠️  Skipping {path} (no changes needed)")
-        return False
-
-    if dry_run:
-        print(f"[DRY RUN] Would patch {path}")
-        return True
-
     path.write_text(content)
     print(f"✅ Patched {path}")
 
@@ -315,17 +308,21 @@ def patch_vite_config(
         print(f"❌ Cannot patch {path} - file not found")
         return False
 
-    original_content = path.read_text()
+    content = path.read_text()
     marker = "vite-plugin-fastapi"
 
-    if marker in original_content:
+    if marker in content:
-        print(f"✔️  {path} (already patched)")
+        print(f"⚠️  Skipping {path} (already patched)")
         return False
 
+    if dry_run:
+        print(f"[DRY RUN] Would patch {path}")
+        return True
+
     # Add import for the plugin at the top (after other imports)
     import_line = f"import fastapiVue from './{marker}.js'"
 
-    lines = original_content.split("\n")
+    lines = content.split("\n")
     new_lines = []
     import_inserted = False
 
@@ -357,18 +354,6 @@ def patch_vite_config(
     if match:
         insert_pos = match.end()
         content = content[:insert_pos] + "\n    fastapiVue()," + content[insert_pos:]
-    else:
-        print(f"⚠️  Skipping {path} (no plugins array found)")
-        return False
-
-    # Check if content actually changed
-    if content == original_content:
-        print(f"⚠️  Skipping {path} (no changes needed)")
-        return False
-
-    if dry_run:
-        print(f"[DRY RUN] Would patch {path}")
-        return True
 
     path.write_text(content)
     print(f"✅ Patched {path}")
@@ -404,14 +389,16 @@ def patch_frontend_health_check(frontend_dir: Path, dry_run: bool = False) -> bo
         print("⚠️  No Vue file found to patch, skipping frontend health check")
         return False
 
-    original_content = target_file.read_text()
+    content = target_file.read_text()
 
     # Check if already patched
-    if "/api/health" in original_content:
+    if "/api/health" in content:
-        print(f"✔️  {target_file} (already patched)")
+        print(f"⚠️  Skipping {target_file} (already patched)")
         return False
 
-    content = original_content
+    if dry_run:
+        print(f"[DRY RUN] Would patch {target_file}")
+        return True
 
     # Detect if TypeScript (has lang="ts" in script tag)
     is_typescript = 'lang="ts"' in content
@@ -423,95 +410,47 @@ def patch_frontend_health_check(frontend_dir: Path, dry_run: bool = False) -> bo
 
     # Insert script addition before </script>
     script_end_match = re.search(r"</script>", content)
-    if not script_end_match:
+    if script_end_match:
-        print(f"⚠️  Skipping {target_file} (no </script> tag found)")
-        return False
-
         insert_pos = script_end_match.start()
         content = content[:insert_pos] + script_addition + content[insert_pos:]
 
     # Insert status inline - find the best place based on file type
     # For HelloWorld.vue: insert before </h3>
-    # For App.vue (minimal): only patch if it's the default "You did it!" template
+    # For App.vue (minimal): insert before the last </p> in template
     if "HelloWorld" in str(target_file):
         # Insert before closing </h3>
         h3_close = content.find("    </h3>")
         if h3_close == -1:
-            print(
-                f"⚠️  Skipping {target_file} (no </h3> tag found for status insertion)"
-            )
             return False
         before, after = content[:h3_close], content[h3_close:]
         content = f"{before}{indent(STATUS_SPAN_TEMPLATE, '  ')}{after}"
     else:
-        # Minimal App.vue - only patch if it contains the default welcome message
+        # Minimal App.vue - insert before the last </p> before </template>
-        if "<h1>You did it!</h1>" not in content:
-            print(f"⚠️  Skipping {target_file} (not a default Vue template)")
-            return False
-        # Insert before the </p> tag
         template_end = content.find("</template>")
-        if template_end == -1:
+        if template_end != -1:
-            print(f"⚠️  Skipping {target_file} (no </template> tag found)")
+            # Find last </p> before </template>
-            return False
-        # Find </p> before </template>
             last_p = content.rfind("  </p>", 0, template_end)
             if last_p == -1:
-            print(f"⚠️  Skipping {target_file} (no </p> tag found for status insertion)")
                 return False
             before, after = content[:last_p], content[last_p:]
             content = f"{before}{STATUS_SPAN_TEMPLATE}{after}"
 
-    # Check if content actually changed
-    if content == original_content:
-        print(f"⚠️  Skipping {target_file} (no changes needed)")
-        return False
-
-    if dry_run:
-        print(f"[DRY RUN] Would patch {target_file}")
-        return True
-
     target_file.write_text(content)
     print(f"✅ Patched {target_file}")
     return True
 
 
-# Track .new.py files written during setup (for merge notification)
-_new_files_written: list[tuple[Path, Path]] = []
-
-
 def write_file(
     path: Path,
     content: str,
     overwrite: bool = True,
     dry_run: bool = False,
     executable: bool = False,
-    fallback_path: Path | None = None,
 ) -> bool:
-    """Write content to a file, handling existing files and dry-run.
+    """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.
-    """
     exists = path.exists()
     if exists and not overwrite:
-        print(f"ℹ️  Skipping {path} (exists)")
+        print(f"⚠️  Skipping {path} (exists)")
-        return False
-
-    # Check if content is the same
-    if exists:
-        existing_content = path.read_text()
-        if existing_content == content:
-            print(f"✔️  {path} (already up to date)")
-            return False
-
-        # If overwrite requested but file doesn't have upgrade marker
-        if overwrite and UPGRADE_MARKER not in existing_content:
-            if fallback_path is not None:
-                # Write to fallback path instead
-                return _write_fallback_file(
-                    path, fallback_path, content, dry_run, executable
-                )
-            print(f"ℹ️  Skipping {path} (customized by user)")
         return False
 
     if dry_run:
@@ -528,100 +467,47 @@ def write_file(
     return True
 
 
-def _write_fallback_file(
+def merge_pyproject(data: dict, additions: dict, module_name: str) -> dict:
-    original_path: Path,
+    """Merge additions into pyproject.toml data."""
-    fallback_path: Path,
+    result = data.copy()
-    content: str,
-    dry_run: bool,
-    executable: bool,
-) -> bool:
-    """Write content to a fallback .new.py file when original can't be overwritten."""
-    # Check if fallback already has same content
-    if fallback_path.exists():
-        if fallback_path.read_text() == content:
-            print(f"✔️  {fallback_path} (already up to date)")
-            return False
 
-    if dry_run:
-        print(f"[DRY RUN] Would create {fallback_path} (original customized by user)")
-        _new_files_written.append((fallback_path, original_path))
-        return True
-
-    fallback_path.parent.mkdir(parents=True, exist_ok=True)
-    fallback_path.write_text(content)
-    if executable and sys.platform != "win32":
-        fallback_path.chmod(fallback_path.stat().st_mode | 0o111)
-    print(f"✅ Created {fallback_path} (original customized by user)")
-    _new_files_written.append((fallback_path, original_path))
-    return True
-
-
-def merge_pyproject(
-    data: tomlkit.TOMLDocument, additions: dict, module_name: str
-) -> tomlkit.TOMLDocument:
-    """Merge additions into pyproject.toml data, preserving comments and existing values."""
     # Ensure hatchling build system is configured
-    if "build-system" not in data:
+    if "build-system" not in result:
-        data["build-system"] = tomlkit.table()
+        result["build-system"] = {}
+    result["build-system"]["requires"] = ["hatchling"]
+    result["build-system"]["build-backend"] = "hatchling.build"
 
-    # Add hatchling to requires if not present, preserving existing requires
+    # Add dependencies
-    if "requires" not in data["build-system"]:
+    if "project" not in result:
-        data["build-system"]["requires"] = ["hatchling"]
+        result["project"] = {}
-    else:
+    if "dependencies" not in result["project"]:
-        requires = list(data["build-system"]["requires"])
+        result["project"]["dependencies"] = []
-        if not any(r.startswith("hatchling") for r in requires):
-            requires.insert(0, "hatchling")
-            data["build-system"]["requires"] = requires
-
-    if "build-backend" not in data["build-system"]:
-        data["build-system"]["build-backend"] = "hatchling.build"
-
-    # Ensure project table exists
-    if "project" not in data:
-        data["project"] = tomlkit.table()
 
     # Add hatch build config
-    if "tool" not in data:
+    if "tool" not in result:
-        data["tool"] = tomlkit.table()
+        result["tool"] = {}
-    if "hatch" not in data["tool"]:
+    if "hatch" not in result["tool"]:
-        data["tool"]["hatch"] = tomlkit.table()
+        result["tool"]["hatch"] = {}
-    if "build" not in data["tool"]["hatch"]:
+    if "build" not in result["tool"]["hatch"]:
-        data["tool"]["hatch"]["build"] = tomlkit.table()
+        result["tool"]["hatch"]["build"] = {}
 
-    hatch_build = data["tool"]["hatch"]["build"]
+    hatch_build = additions["tool"]["hatch"]["build"]
-    hatch_additions = additions["tool"]["hatch"]["build"]
+    result["tool"]["hatch"]["build"]["packages"] = [
+        p.replace("MODULE_NAME", module_name) for p in hatch_build["packages"]
+    ]
+    result["tool"]["hatch"]["build"]["artifacts"] = [
+        a.replace("MODULE_NAME", module_name) for a in hatch_build["artifacts"]
+    ]
+    result["tool"]["hatch"]["build"]["only-packages"] = hatch_build["only-packages"]
 
-    # Set packages if not already set
+    if "targets" not in result["tool"]["hatch"]["build"]:
-    if "packages" not in hatch_build:
+        result["tool"]["hatch"]["build"]["targets"] = {}
-        hatch_build["packages"] = [
+
-            p.replace("MODULE_NAME", module_name) for p in hatch_additions["packages"]
+    result["tool"]["hatch"]["build"]["targets"]["sdist"] = hatch_build["targets"][
+        "sdist"
     ]
 
-    # Set artifacts if not already set
+    return result
-    if "artifacts" not in hatch_build:
-        hatch_build["artifacts"] = [
-            a.replace("MODULE_NAME", module_name) for a in hatch_additions["artifacts"]
-        ]
-
-    # Set only-packages if not already set
-    if "only-packages" not in hatch_build:
-        hatch_build["only-packages"] = hatch_additions["only-packages"]
-
-    # Add sdist target with custom hook
-    if "targets" not in hatch_build:
-        hatch_build["targets"] = tomlkit.table()
-    if "sdist" not in hatch_build["targets"]:
-        hatch_build["targets"]["sdist"] = tomlkit.table()
-    if "hooks" not in hatch_build["targets"]["sdist"]:
-        hatch_build["targets"]["sdist"]["hooks"] = tomlkit.table()
-    if "custom" not in hatch_build["targets"]["sdist"]["hooks"]:
-        hatch_build["targets"]["sdist"]["hooks"]["custom"] = tomlkit.table()
-    if "path" not in hatch_build["targets"]["sdist"]["hooks"]["custom"]:
-        hatch_build["targets"]["sdist"]["hooks"]["custom"]["path"] = hatch_additions[
-            "targets"
-        ]["sdist"]["hooks"]["custom"]["path"]
-
-    return data
 
 
 # =============================================================================
@@ -819,38 +705,25 @@ def cmd_setup(args: argparse.Namespace) -> int:
             module_dir.mkdir(parents=True)
 
     # === Install scripts (always update our own scripts) ===
-    # util.py and build-frontend.py are internal and always overwritten
+    script_files = [
-    # 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",
         ),
+        (scripts_dir / "devserver.py", "scripts/devserver.py"),
     ]
 
-    for dest_path, template_path in internal_script_files:
+    for dest_path, template_path in script_files:
         template = load_template(template_path)
         content = render_template(template, **tpl_vars)
+        is_executable = dest_path.name == "devserver.py"
         write_file(
             dest_path,
             content,
             overwrite=True,
             dry_run=dry_run,
-        )
+            executable=is_executable,
-
-    # devserver.py - use fallback if customized by user
-    devserver_path = scripts_dir / "devserver.py"
-    devserver_fallback = scripts_dir / "devserver.new.py"
-    template = load_template("scripts/devserver.py")
-    content = render_template(template, **tpl_vars)
-    write_file(
-        devserver_path,
-        content,
-        overwrite=True,
-        dry_run=dry_run,
-        executable=True,
-        fallback_path=devserver_fallback,
         )
 
     # === Handle app module ===
@@ -874,21 +747,10 @@ def cmd_setup(args: argparse.Namespace) -> int:
 
     # === Handle __main__.py ===
     main_file = module_dir / "__main__.py"
-    main_fallback = module_dir / "__main__.new.py"
+    if not main_file.exists():
         template = load_template("backend/__main__.py")
-    main_content = render_template(template, **tpl_vars)
+        content = render_template(template, **tpl_vars)
-
+        write_file(main_file, content, overwrite=False, dry_run=dry_run)
-    # Use write_file with fallback - it handles all cases:
-    # - File doesn't exist: create it
-    # - File exists with marker: update it
-    # - File exists without marker: write to fallback
-    write_file(
-        main_file,
-        main_content,
-        overwrite=True,
-        dry_run=dry_run,
-        fallback_path=main_fallback,
-    )
 
     # === Update vite.config.js/ts ===
     frontend_dir = project_dir / "frontend"
@@ -917,43 +779,39 @@ def cmd_setup(args: argparse.Namespace) -> int:
     # === Update pyproject.toml ===
     pyproject_path = project_dir / "pyproject.toml"
     if pyproject_path.exists():
-        old_content = pyproject_path.read_text()
+        with open(pyproject_path, "rb") as f:
-        data = tomlkit.parse(old_content)
+            data = tomllib.load(f)
 
         updated = merge_pyproject(data, PYPROJECT_ADDITIONS, module_name)
 
-        # Only add script entry if project doesn't already have scripts
+        # Add script entry pointing to the app we found/created
-        if "scripts" not in updated["project"] or not updated["project"]["scripts"]:
+        if "scripts" not in updated["project"]:
-            updated["project"]["scripts"] = tomlkit.table()
+            updated["project"]["scripts"] = {}
         script_name = module_name.replace("_", "-")
         updated["project"]["scripts"][script_name] = f"{module_name}.__main__:main"
 
-        # Check if content actually changed
+        if dry_run:
-        new_content = tomlkit.dumps(updated)
-
-        if new_content == old_content:
-            print(f"✔️  {pyproject_path} (already up to date)")
-        elif dry_run:
             print(f"[DRY RUN] Would update {pyproject_path}")
         else:
-            pyproject_path.write_text(new_content)
+            with open(pyproject_path, "wb") as f:
+                tomli_w.dump(updated, f)
             print(f"✅ Updated {pyproject_path}")
 
     # === Add dependencies using uv ===
     if dry_run:
-        print("[DRY RUN] Would run: uv add -U 'fastapi[standard]' fastapi-vue")
+        print("[DRY RUN] Would run: uv add 'fastapi[standard]' fastapi-vue")
-        print("[DRY RUN] Would run: uv add -U --group dev httpx")
+        print("[DRY RUN] Would run: uv add --group dev httpx")
     else:
         print("📦 Adding dependencies...")
         result = subprocess.run(
-            ["uv", "add", "-U", "fastapi[standard]", "fastapi-vue"],
+            ["uv", "add", "fastapi[standard]", "fastapi-vue"],
             cwd=project_dir,
             check=False,
         )
         if result.returncode != 0:
             print("⚠️  Failed to add main dependencies")
         result = subprocess.run(
-            ["uv", "add", "-U", "--group", "dev", "httpx"],
+            ["uv", "add", "--group", "dev", "httpx"],
             cwd=project_dir,
             check=False,
         )
@@ -994,19 +852,6 @@ def cmd_setup(args: argparse.Namespace) -> int:
     )
     print(message)
 
-    # Show merge note if any .new.py files were written
-    if _new_files_written:
-        print()
-        print(
-            "⚠️  Note: Some files could not be auto-upgraded because you customized them."
-        )
-        print("   Please manually merge the following files:")
-        for new_file, original_file in _new_files_written:
-            print(f"     • {new_file.name} → {original_file.name}")
-        print()
-        # Clear the list for potential subsequent runs
-        _new_files_written.clear()
-
     return 0
 
 
@@ -1056,6 +901,11 @@ Examples:
     parser.add_argument(
         "--dry-run", action="store_true", help="Show what would be done"
     )
+    parser.add_argument(
+        "--version",
+        action="version",
+        version=f"%(prog)s {__version__}",
+    )
 
     args = parser.parse_args()
 

pyproject.toml

@@ -9,7 +9,7 @@ description = "Tool to create or patch FastAPI+Vue projects with integrated buil
 readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
-    "tomlkit>=0.12.0",
+    "tomli-w>=1.0.0",
 ]
 
 [project.urls]
@@ -22,6 +22,9 @@ fastapi-vue-setup = "fastapi_vue_setup:main"
 [tool.hatch.version]
 source = "vcs"
 
+[tool.hatch.build.hooks.vcs]
+version-file = "_version.py"
+
 [tool.hatch.build.targets.wheel]
 include = ["fastapi_vue_setup.py", "template/**/*", "_version.py"]
 

template/backend/__main__.py

@@ -1,4 +1,3 @@
-# auto-upgrade@fastapi-vue-setup - remove this if you modify this file
 import argparse
 import asyncio
 import os

template/scripts/devserver.py

@@ -1,5 +1,4 @@
 #!/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.
 
 Usage:
@@ -17,15 +16,17 @@ Environment:
 import argparse
 import asyncio
 import contextlib
+import ipaddress
 import os
 from pathlib import Path
 from sys import stderr
+from urllib.parse import urlparse
 
 import httpx
-from fastapi_vue.hostutil import parse_endpoint
 
 exec((Path(__file__).parent / "fastapi-vue/util.py").read_text("UTF-8"))  # noqa: S102
 
+DEFAULT_HOST = "localhost"
 DEFAULT_VITE_PORT = 5173
 DEFAULT_BACKEND_PORT = 5180
 FRONTEND_PATH = Path(__file__).parent.parent / "frontend"
@@ -44,8 +45,45 @@ BUN_BUG = """\
 """
 
 
+def parse_endpoint(
+    value: str | None, default_port: int = DEFAULT_VITE_PORT
+) -> tuple[str | None, int, bool]:
+    """Parse an endpoint for Vite or backend.
+
+    Returns (host, port, all_ifaces).
+    """
+    if not value:
+        return DEFAULT_HOST, default_port, False
+
+    # Port only (numeric) -> localhost:port
+    if value.isdigit():
+        return DEFAULT_HOST, int(value), False
+
+    # Leading colon :port -> bind all interfaces
+    if value.startswith(":") and value != ":":
+        port_part = value[1:]
+        if not port_part.isdigit():
+            raise SystemExit(f"Invalid port in '{value}'")
+        return None, int(port_part), True
+
+    # Unbracketed IPv6 (cannot safely contain a port)
+    if value.count(":") > 1 and not value.startswith("["):
+        try:
+            ipaddress.IPv6Address(value)
+        except ValueError as e:
+            raise SystemExit(f"Invalid IPv6 address '{value}': {e}") from e
+        return value, default_port, False
+
+    # Use urllib.parse for everything else
+    parsed = urlparse(f"//{value}")
+    host = parsed.hostname or DEFAULT_HOST
+    port = parsed.port or default_port
+
+    return host, port, False
+
+
 def resolve_frontend_tools(
-    vite_port: int, all_ifaces: bool
+    vite_host: str | None, vite_port: int, all_ifaces: bool
 ) -> tuple[list[str], list[str], str]:
     """Resolve frontend install and dev commands.
 
@@ -85,6 +123,8 @@ def resolve_frontend_tools(
 
     if all_ifaces:
         dev_cmd.append("--host")
+    elif vite_host and vite_host != "localhost":
+        dev_cmd.append(f"--host={vite_host}")
 
     if name == "bun":
         stderr.write(BUN_BUG)
@@ -92,15 +132,13 @@ def resolve_frontend_tools(
     return install_cmd, dev_cmd, name
 
 
-async def wait_for_backend(host: str, port: int):
+async def wait_for_backend(backend_host: str, backend_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)
+                await client.get(f"http://{backend_host}:{backend_port}", timeout=1.0)
                 stderr.write("✓ Backend ready!\n")
                 return True
             except httpx.RequestError:
@@ -130,29 +168,23 @@ async def _terminate_process(proc: asyncio.subprocess.Process, name: str) -> Non
 
 
 async def run_devserver(
+    vite_host: str | None,
     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)
+    install_cmd, dev_cmd, tool_name = resolve_frontend_tools(
+        vite_host, vite_port, all_ifaces
+    )
 
     # Tell the backend where the Vite dev server is
-    os.environ["FASTAPI_VUE_FRONTEND_URL"] = f"http://localhost:{vite_port}"
+    os.environ["FASTAPI_VUE_FRONTEND_URL"] = (
+        f"http://{vite_host or '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)
 
@@ -170,6 +202,15 @@ async def run_devserver(
         await asyncio.sleep(0.1)
 
         # Start backend (concurrent with install)
+        backend_cmd = [
+            "uvicorn",
+            "MODULE_NAME.app:app",
+            "--host",
+            backend_host,
+            "--port",
+            str(backend_port),
+            "--reload",
+        ]
         stderr.write(f">>> {' '.join(backend_cmd)}\n")
         backend_proc = await asyncio.create_subprocess_exec(*backend_cmd, cwd=cwd)
 
@@ -251,26 +292,15 @@ def main():
     )
     args = parser.parse_args()
 
-    # parse_endpoint returns list of dicts with host/port or uds keys
+    vite_host, vite_port, all_ifaces = parse_endpoint(args.frontend, DEFAULT_VITE_PORT)
-    # Multiple entries means bind all interfaces (IPv4 + IPv6)
+    backend_host, backend_port, _ = parse_endpoint(args.backend, DEFAULT_BACKEND_PORT)
-    vite_endpoints = parse_endpoint(args.frontend, DEFAULT_VITE_PORT)
+    # Backend host defaults to localhost (never None)
-    backend_endpoints = parse_endpoint(args.backend, DEFAULT_BACKEND_PORT)
+    backend_host = backend_host or DEFAULT_HOST
-
-    # 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(vite_host, vite_port, all_ifaces, backend_host, backend_port)
+        )
 
 
 if __name__ == "__main__":