diff --git a/.src/openapi_mock/cli/cli.py b/.src/openapi_mock/cli/cli.py
new file mode 100644
index 0000000..599fc30
--- /dev/null
+++ b/.src/openapi_mock/cli/cli.py
@@ -0,0 +1,307 @@
+"""CLI interface for OpenAPI Mock Server."""
+
+import os
+import sys
+import signal
+import threading
+from pathlib import Path
+from typing import Optional
+
+import click
+import uvicorn
+
+from openapi_mock.server.server import create_app
+from openapi_mock.core.spec_parser import load_spec, SpecNotFoundError, SpecValidationError
+
+
+def validate_delay(ctx: click.Context, param: click.Parameter, value: str) -> Optional[tuple]:
+    """Validate and parse delay option."""
+    if value is None:
+        return None
+
+    try:
+        if "," in value:
+            parts = value.split(",")
+            if len(parts) == 2:
+                return (float(parts[0].strip()), float(parts[1].strip()))
+        return (float(value), float(value))
+    except ValueError:
+        raise click.BadParameter(
+            "Invalid delay format. Use --delay 0.5 or --delay 0.1,1.0"
+        )
+
+
+def validate_port(ctx: click.Context, param: click.Parameter, value: int) -> int:
+    """Validate port number."""
+    if value < 1 or value > 65535:
+        raise click.BadParameter("Port must be between 1 and 65535")
+    return value
+
+
+@click.group()
+def main() -> None:
+    """OpenAPI Mock Server - Generate mock API servers from OpenAPI specifications."""
+    pass
+
+
+@click.command()
+@click.argument(
+    "spec",
+    type=click.Path(exists=True, file_okay=True, dir_okay=False, readable=True),
+)
+@click.option(
+    "--host",
+    default="127.0.0.1",
+    help="Host address to bind to",
+    show_default=True,
+)
+@click.option(
+    "--port",
+    type=int,
+    default=8080,
+    help="Port to run the mock server on",
+    callback=validate_port,
+    show_default=True,
+)
+@click.option(
+    "--delay",
+    type=str,
+    default=None,
+    help="Response delay in seconds (e.g., 0.5 or 0.1,1.0 for range)",
+    callback=validate_delay,
+)
+@click.option(
+    "--watch/--no-watch",
+    default=False,
+    help="Enable hot-reload when spec file changes",
+)
+@click.option(
+    "--auth",
+    type=click.Choice(["none", "bearer", "api_key", "basic"], case_sensitive=False),
+    default="none",
+    help="Authentication type to simulate",
+    show_default=True,
+)
+@click.option(
+    "--reload/--no-reload",
+    default=False,
+    help="Automatically reload server on changes (for development)",
+)
+def start(
+    spec: str,
+    host: str,
+    port: int,
+    delay: Optional[tuple],
+    watch: bool,
+    auth: str,
+    reload: bool,
+) -> None:
+    """Start the mock server from an OpenAPI specification file.
+
+    SPEC is the path to the OpenAPI YAML or JSON specification file.
+    """
+    spec_path = Path(spec).resolve()
+
+    try:
+        spec_data = load_spec(str(spec_path))
+        click.echo(f"Loaded OpenAPI spec: {spec_path}")
+        click.echo(f"API Title: {spec_data.get('info', {}).get('title', 'Unknown')}")
+        click.echo(f"Version: {spec_data.get('info', {}).get('version', 'Unknown')}")
+    except SpecNotFoundError:
+        click.echo(f"Error: Spec file not found: {spec_path}", err=True)
+        sys.exit(1)
+    except SpecValidationError as e:
+        click.echo(f"Error: Invalid OpenAPI spec: {e}", err=True)
+        sys.exit(1)
+    except Exception as e:
+        click.echo(f"Error loading spec: {e}", err=True)
+        sys.exit(1)
+
+    if watch:
+        from openapi_mock.server.hot_reload import FileWatcher
+
+        watcher = FileWatcher(str(spec_path), port, host, delay, auth)
+
+        signal.signal(signal.SIGINT, lambda s, f: watcher.stop())
+        signal.signal(signal.SIGTERM, lambda s, f: watcher.stop())
+
+        click.echo(f"Starting hot-reload server at http://{host}:{port}")
+        click.echo(f"Watching for changes to: {spec_path}")
+        click.echo("Press Ctrl+C to stop")
+
+        try:
+            watcher.run()
+        except KeyboardInterrupt:
+            watcher.stop()
+        return
+
+    if auth != "none":
+        click.echo(f"Authentication enabled: {auth}")
+
+    if delay:
+        if delay[0] == delay[1]:
+            click.echo(f"Response delay: {delay[0]}s")
+        else:
+            click.echo(f"Response delay: {delay[0]}s - {delay[1]}s")
+
+    config = uvicorn.Config(
+        create_app(str(spec_path), delay_range=delay, auth_type=auth),
+        host=host,
+        port=port,
+        reload=reload,
+    )
+    server = uvicorn.Server(config)
+
+    click.echo(f"\nStarting mock server at http://{host}:{port}")
+    click.echo("Press Ctrl+C to stop\n")
+
+    try:
+        server.run()
+    except KeyboardInterrupt:
+        click.echo("\nShutting down server...")
+
+
+@click.command()
+@click.argument(
+    "spec",
+    type=click.Path(exists=True, file_okay=True, dir_okay=False, readable=True),
+)
+@click.option(
+    "--output",
+    "-o",
+    type=click.Path(file_okay=True, dir_okay=False, writable=True),
+    help="Output file for the generated app (default: stdout)",
+)
+def generate(spec: str, output: Optional[str]) -> None:
+    """Generate a standalone Python file with the mock server.
+
+    SPEC is the path to the OpenAPI YAML or JSON specification file.
+    """
+    spec_path = Path(spec).resolve()
+
+    try:
+        spec_data = load_spec(str(spec_path))
+    except (SpecNotFoundError, SpecValidationError) as e:
+        click.echo(f"Error: {e}", err=True)
+        sys.exit(1)
+
+    title = spec_data.get("info", {}).get("title", "Mock API")
+    version = spec_data.get("info", {}).get("version", "1.0.0")
+
+    code = f'''\"\"\"Auto-generated mock server from OpenAPI spec: {spec_path.name}\"\"\"
+
+from fastapi import FastAPI
+from openapi_mock.generators.data_generator import DataGenerator
+
+app = FastAPI(
+    title="{title}",
+    version="{version}",
+)
+
+generator = DataGenerator()
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run(app, host="127.0.0.1", port=8080)
+'''
+
+    if output:
+        Path(output).write_text(code)
+        click.echo(f"Generated mock server: {output}")
+    else:
+        click.echo(code)
+
+
+@click.command()
+@click.argument(
+    "spec",
+    type=click.Path(exists=True, file_okay=True, dir_okay=False, readable=True),
+)
+def validate(spec: str) -> None:
+    """Validate an OpenAPI specification file.
+
+    SPEC is the path to the OpenAPI YAML or JSON specification file.
+    """
+    spec_path = Path(spec).resolve()
+
+    try:
+        spec_data = load_spec(str(spec_path))
+        click.echo(f"Valid OpenAPI spec: {spec_path}")
+        click.echo(f"  Title: {spec_data.get('info', {}).get('title', 'Unknown')}")
+        click.echo(f"  Version: {spec_data.get('info', {}).get('version', 'Unknown')}")
+
+        paths = spec_data.get("paths", {})
+        click.echo(f"  Paths: {len(paths)}")
+
+        schemas = spec_data.get("components", {}).get("schemas", {})
+        if not schemas and "definitions" in spec_data:
+            schemas = spec_data.get("definitions", {})
+        click.echo(f"  Schemas: {len(schemas)}")
+
+        click.echo("\nSpecification is valid")
+    except SpecNotFoundError:
+        click.echo(f"Spec file not found: {spec_path}", err=True)
+        sys.exit(1)
+    except SpecValidationError as e:
+        click.echo(f"Invalid OpenAPI spec: {e}", err=True)
+        sys.exit(1)
+    except Exception as e:
+        click.echo(f"Error: {e}", err=True)
+        sys.exit(1)
+
+
+@click.command()
+@click.argument(
+    "spec",
+    type=click.Path(exists=True, file_okay=True, dir_okay=False, readable=True),
+)
+def info(spec: str) -> None:
+    """Display information about an OpenAPI specification.
+
+    SPEC is the path to the OpenAPI YAML or JSON specification file.
+    """
+    spec_path = Path(spec).resolve()
+
+    try:
+        spec_data = load_spec(str(spec_path))
+    except (SpecNotFoundError, SpecValidationError) as e:
+        click.echo(f"Error: {e}", err=True)
+        sys.exit(1)
+
+    info_data = spec_data.get("info", {})
+
+    click.echo(f"Title: {info_data.get('title', 'Unknown')}")
+    click.echo(f"Version: {info_data.get('version', 'Unknown')}")
+    click.echo(f"Description: {info_data.get('description', 'N/A')}")
+
+    if info_data.get("contact"):
+        contact = info_data["contact"]
+        click.echo(f"Contact: {contact.get('name', 'N/A')} <{contact.get('email', 'N/A')}>")
+
+    if info_data.get("license"):
+        license_info = info_data["license"]
+        click.echo(f"License: {license_info.get('name', 'N/A')}")
+
+    paths = spec_data.get("paths", {})
+    click.echo(f"\nPaths ({len(paths)}):")
+    for path, methods in sorted(paths.items()):
+        for method in sorted(methods.keys()):
+            if method.upper() in ["GET", "POST", "PUT", "DELETE", "PATCH", "OPTIONS", "HEAD"]:
+                operation = methods.get(method, {})
+                summary = operation.get("summary", "")
+                click.echo(f"  {method.upper():7} {path} {'- ' + summary if summary else ''}")
+
+    schemas = spec_data.get("components", {}).get("schemas", {})
+    if not schemas and "definitions" in spec_data:
+        schemas = spec_data.get("definitions", {})
+
+    if schemas:
+        click.echo(f"\nSchemas ({len(schemas)}):")
+        for name in sorted(schemas.keys()):
+            schema = schemas[name]
+            props = schema.get("properties", {})
+            click.echo(f"  {name} ({len(props)} properties)")
+
+
+if __name__ == "__main__":
+    main()