diff --git a/backend/flutter_manual_api.py b/backend/flutter_manual_api.py
new file mode 100644
index 0000000..e031192
--- /dev/null
+++ b/backend/flutter_manual_api.py
@@ -0,0 +1,147 @@
+import json
+import os
+import signal
+import subprocess
+import time
+import uuid
+from pathlib import Path
+
+from fastapi import APIRouter, HTTPException
+from fastapi.responses import StreamingResponse
+from pydantic import BaseModel
+
+from backend.runtime_logs import add_log
+
+router = APIRouter(prefix='/api/runtime', tags=['runtime-flutter-manual'])
+ACTIVE_MANUAL_FLUTTER: dict[str, subprocess.Popen] = {}
+
+ALLOWED_FIRST_WORDS = {
+    'analyze',
+    'assemble',
+    'attach',
+    'build',
+    'channel',
+    'clean',
+    'config',
+    'devices',
+    'doctor',
+    'drive',
+    'emulators',
+    'gen-l10n',
+    'logs',
+    'packages',
+    'precache',
+    'pub',
+    'run',
+    'screenshot',
+    'test',
+    'upgrade',
+    'version',
+}
+
+
+class ManualFlutterRequest(BaseModel):
+    workspace: str
+    args: str
+    device: str | None = None
+    timeout: int | None = 3600
+
+
+def _runtime_env() -> dict:
+    runtime_home = os.getenv('DEVCONSOLE_RUNTIME_HOME') or os.getenv('HOME') or '/home/devconsole'
+    flutter_home = os.getenv('FLUTTER_HOME') or f'{runtime_home}/flutter'
+    android_home = os.getenv('ANDROID_HOME') or os.getenv('ANDROID_SDK_ROOT') or f'{runtime_home}/Android'
+    pub_cache = os.getenv('PUB_CACHE') or f'{runtime_home}/.pub-cache'
+    env = os.environ.copy()
+    env.update({
+        'HOME': runtime_home,
+        'PUB_CACHE': pub_cache,
+        'ANDROID_HOME': android_home,
+        'ANDROID_SDK_ROOT': android_home,
+        'PATH': f'{flutter_home}/bin:{android_home}/cmdline-tools/latest/bin:{android_home}/platform-tools:' + env.get('PATH', ''),
+    })
+    return env
+
+
+def _workspace_cwd(workspace: str) -> str:
+    path = Path(workspace).resolve()
+    if not path.exists():
+        raise HTTPException(status_code=400, detail='Workspace path does not exist')
+    return path.as_posix()
+
+
+def _split_args(raw_args: str) -> list[str]:
+    cleaned = (raw_args or '').strip()
+    if not cleaned:
+        raise HTTPException(status_code=400, detail='Flutter command is empty')
+    if cleaned.startswith('flutter '):
+        cleaned = cleaned[len('flutter '):].strip()
+    if any(ch in cleaned for ch in ['\n', '\r', '\x00']):
+        raise HTTPException(status_code=400, detail='Invalid Flutter command')
+    parts = cleaned.split()
+    if not parts:
+        raise HTTPException(status_code=400, detail='Flutter command is empty')
+    if parts[0] not in ALLOWED_FIRST_WORDS:
+        raise HTTPException(status_code=400, detail='Unsupported Flutter subcommand')
+    return parts
+
+
+def _event(payload: dict) -> str:
+    return json.dumps(payload, ensure_ascii=False) + '\n'
+
+
+def _stream_manual_flutter(workspace: str, args: str, device: str | None, timeout: int):
+    cwd = _workspace_cwd(workspace)
+    parts = _split_args(args)
+    if device and '-d' not in parts and '--device-id' not in parts:
+        parts.extend(['-d', device])
+    command = ['flutter', *parts]
+    task_id = uuid.uuid4().hex
+
+    process = subprocess.Popen(
+        command,
+        cwd=cwd,
+        env=_runtime_env(),
+        text=True,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT,
+        stdin=subprocess.PIPE,
+        bufsize=1,
+        preexec_fn=os.setsid,
+    )
+    ACTIVE_MANUAL_FLUTTER[task_id] = process
+    add_log('Manual Flutter command started: ' + ' '.join(command))
+    yield _event({'type': 'start', 'task_id': task_id, 'message': ' '.join(command)})
+
+    started_at = time.time()
+    try:
+        assert process.stdout is not None
+        while True:
+            if time.time() - started_at > timeout:
+                yield _event({'type': 'error', 'task_id': task_id, 'message': 'Manual Flutter command timeout'})
+                break
+            line = process.stdout.readline()
+            if line:
+                yield _event({'type': 'line', 'task_id': task_id, 'message': line.rstrip()})
+                continue
+            if process.poll() is not None:
+                break
+            time.sleep(0.1)
+        returncode = process.poll()
+        if returncode is None:
+            os.killpg(os.getpgid(process.pid), signal.SIGTERM)
+            returncode = -1
+    finally:
+        ACTIVE_MANUAL_FLUTTER.pop(task_id, None)
+
+    add_log('Manual Flutter command finished: ' + ' '.join(command) + f' exit {returncode}')
+    yield _event({'type': 'done', 'task_id': task_id, 'returncode': returncode})
+
+
+@router.post('/flutter-manual-stream')
+async def flutter_manual_stream(payload: ManualFlutterRequest):
+    timeout = max(30, min(int(payload.timeout or 3600), 7200))
+    return StreamingResponse(
+        _stream_manual_flutter(payload.workspace, payload.args, payload.device, timeout),
+        media_type='application/x-ndjson',
+    )