diff --git a/examples/online_serving/helios/README.md b/examples/online_serving/helios/README.md
new file mode 100644
index 000000000..5e13df19d
--- /dev/null
+++ b/examples/online_serving/helios/README.md
@@ -0,0 +1,175 @@
+# Helios Video Generation via Online API
+
+This example demonstrates how to use the `/v1/videos` API with Helios models using the generic `extra_params` field.
+
+## Overview
+
+The `/v1/videos` API now supports model-specific parameters through the `extra_params` field, which accepts a JSON object containing any model-specific configuration. This allows supporting new models like Helios without modifying the API.
+
+## Helios Model Variants
+
+- **Helios-Base**: Basic T2V/I2V/V2V generation (Stage 1 only)
+- **Helios-Mid**: Advanced generation with CFG-Zero* (Stage 2)
+- **Helios-Distilled**: Fast generation with DMD (Stage 2)
+
+## API Usage Examples
+
+### 1. T2V (Text-to-Video) - Helios-Base
+
+Basic text-to-video generation:
+
+```bash
+curl -X POST http://localhost:8000/v1/videos \
+  -F "prompt=A serene lakeside sunrise with mist over the water." \
+  -F "model=BestWishYsh/Helios-Base" \
+  -F "width=640" \
+  -F "height=384" \
+  -F "num_frames=99" \
+  -F "num_inference_steps=50" \
+  -F "guidance_scale=5.0" \
+  -F "seed=42"
+```
+
+### 2. I2V (Image-to-Video) - Helios-Base
+
+Generate video from an input image:
+
+```bash
+curl -X POST http://localhost:8000/v1/videos \
+  -F "prompt=The lake water gently ripples as morning mist rises." \
+  -F "model=BestWishYsh/Helios-Base" \
+  -F "input_reference=@/path/to/image.jpg" \
+  -F "width=640" \
+  -F "height=384" \
+  -F "num_frames=99" \
+  -F "guidance_scale=5.0"
+```
+
+### 3. Helios-Mid with Stage 2 + CFG-Zero*
+
+Advanced generation with pyramid multi-stage denoising:
+
+```bash
+curl -X POST http://localhost:8000/v1/videos \
+  -F "prompt=A serene lakeside sunrise with mist over the water." \
+  -F "model=BestWishYsh/Helios-Mid" \
+  -F "width=640" \
+  -F "height=384" \
+  -F "guidance_scale=5.0" \
+  -F 'extra_params={
+    "is_enable_stage2": true,
+    "pyramid_num_stages": 3,
+    "pyramid_num_inference_steps_list": [20, 20, 20],
+    "use_cfg_zero_star": true,
+    "use_zero_init": true,
+    "zero_steps": 1
+  }'
+```
+
+### 4. Helios-Distilled with DMD
+
+Fast generation with Distribution Matching Distillation:
+
+```bash
+curl -X POST http://localhost:8000/v1/videos \
+  -F "prompt=A serene lakeside sunrise with mist over the water." \
+  -F "model=BestWishYsh/Helios-Distilled" \
+  -F "width=640" \
+  -F "height=384" \
+  -F "guidance_scale=1.0" \
+  -F 'extra_params={
+    "is_enable_stage2": true,
+    "pyramid_num_stages": 3,
+    "pyramid_num_inference_steps_list": [2, 2, 2],
+    "is_amplify_first_chunk": true
+  }'
+```
+
+## Model-Specific Parameters
+
+The `extra_params` field accepts a JSON object with model-specific parameters. For Helios models, supported parameters include:
+
+### Stage 2 Parameters
+- `is_enable_stage2` (bool): Enable pyramid multi-stage denoising
+- `pyramid_num_stages` (int): Number of pyramid stages (default: 3)
+- `pyramid_num_inference_steps_list` (array): Steps per stage, e.g., `[20, 20, 20]`
+
+### CFG Zero Star Parameters (Helios-Mid)
+- `use_cfg_zero_star` (bool): Enable CFG Zero Star guidance
+- `use_zero_init` (bool): Use zero initialization for first steps
+- `zero_steps` (int): Number of initial zero prediction steps (default: 1)
+
+### DMD Parameters (Helios-Distilled)
+- `is_amplify_first_chunk` (bool): Enable DMD amplification for first chunk
+
+### Video Input (V2V mode)
+For video-to-video generation, upload a video file via `input_reference`:
+
+```bash
+curl -X POST http://localhost:8000/v1/videos \
+  -F "prompt=Transform the video into a watercolor painting style." \
+  -F "model=BestWishYsh/Helios-Base" \
+  -F "input_reference=@/path/to/video.mp4" \
+  -F "guidance_scale=5.0"
+```
+
+## Python Example
+
+```python
+import requests
+import json
+
+url = "http://localhost:8000/v1/videos"
+
+# Helios-Mid with Stage 2
+data = {
+    "prompt": "A serene lakeside sunrise with mist over the water.",
+    "model": "BestWishYsh/Helios-Mid",
+    "width": 640,
+    "height": 384,
+    "guidance_scale": 5.0,
+    "extra_params": json.dumps({
+        "is_enable_stage2": True,
+        "pyramid_num_stages": 3,
+        "pyramid_num_inference_steps_list": [20, 20, 20],
+        "use_cfg_zero_star": True,
+        "use_zero_init": True,
+        "zero_steps": 1
+    })
+}
+
+response = requests.post(url, data=data)
+video_job = response.json()
+print(f"Video job created: {video_job['id']}")
+
+# Poll for completion
+import time
+while True:
+    status_response = requests.get(f"{url}/{video_job['id']}")
+    status = status_response.json()
+
+    if status['status'] == 'completed':
+        print(f"Video generated: {status['file_name']}")
+        break
+    elif status['status'] == 'failed':
+        print(f"Generation failed: {status.get('error')}")
+        break
+
+    print(f"Progress: {status['progress']}%")
+    time.sleep(2)
+```
+
+## Benefits of This Approach
+
+1. **No API Changes**: New models can be supported without modifying the API
+2. **Backward Compatible**: Existing clients continue to work
+3. **Flexible**: Any model-specific parameter can be passed
+4. **Type-Safe**: Parameters are validated at the model level
+5. **Future-Proof**: Supports models that don't exist yet
+
+## Notes
+
+- The `extra_params` field must be a valid JSON object
+- Parameters are passed directly to the model's `extra_args`
+- Invalid parameters will be caught by the model implementation
+- Tensor inputs (images/videos) should use `input_reference`, not `extra_params`
diff --git a/examples/online_serving/helios/helios_client.py b/examples/online_serving/helios/helios_client.py
new file mode 100644
index 000000000..d50249966
--- /dev/null
+++ b/examples/online_serving/helios/helios_client.py
@@ -0,0 +1,212 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+"""
+Helios video generation client example using the /v1/videos API.
+
+This example demonstrates how to use the generic extra_params field
+to pass Helios-specific parameters without modifying the API.
+"""
+
+import argparse
+import json
+import time
+from pathlib import Path
+
+import requests
+
+
+def create_video_job(
+    api_url: str,
+    prompt: str,
+    model: str,
+    width: int = 640,
+    height: int = 384,
+    num_frames: int = 99,
+    guidance_scale: float = 5.0,
+    seed: int = 42,
+    extra_params: dict | None = None,
+    input_image: Path | None = None,
+) -> dict:
+    """Create a video generation job."""
+    data = {
+        "prompt": prompt,
+        "model": model,
+        "width": width,
+        "height": height,
+        "num_frames": num_frames,
+        "guidance_scale": guidance_scale,
+        "seed": seed,
+    }
+
+    files = {}
+    if input_image:
+        files["input_reference"] = open(input_image, "rb")
+
+    if extra_params:
+        data["extra_params"] = json.dumps(extra_params)
+
+    response = requests.post(f"{api_url}/v1/videos", data=data, files=files)
+    response.raise_for_status()
+
+    if files:
+        files["input_reference"].close()
+
+    return response.json()
+
+
+def poll_video_status(api_url: str, video_id: str, poll_interval: int = 2) -> dict:
+    """Poll video generation status until completion."""
+    print(f"Polling video job: {video_id}")
+
+    while True:
+        response = requests.get(f"{api_url}/v1/videos/{video_id}")
+        response.raise_for_status()
+        status_data = response.json()
+
+        status = status_data["status"]
+        progress = status_data.get("progress", 0)
+
+        print(f"Status: {status}, Progress: {progress}%")
+
+        if status == "completed":
+            print("Video generation completed!")
+            return status_data
+        elif status == "failed":
+            error = status_data.get("error", {})
+            raise RuntimeError(f"Video generation failed: {error}")
+
+        time.sleep(poll_interval)
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Helios video generation client")
+    parser.add_argument(
+        "--api-url",
+        default="http://localhost:8000",
+        help="API server URL",
+    )
+    parser.add_argument(
+        "--model",
+        default="BestWishYsh/Helios-Base",
+        help="Model name (Helios-Base, Helios-Mid, Helios-Distilled)",
+    )
+    parser.add_argument(
+        "--prompt",
+        default="A serene lakeside sunrise with mist over the water.",
+        help="Text prompt",
+    )
+    parser.add_argument(
+        "--width",
+        type=int,
+        default=640,
+        help="Video width",
+    )
+    parser.add_argument(
+        "--height",
+        type=int,
+        default=384,
+        help="Video height",
+    )
+    parser.add_argument(
+        "--num-frames",
+        type=int,
+        default=99,
+        help="Number of frames",
+    )
+    parser.add_argument(
+        "--guidance-scale",
+        type=float,
+        default=5.0,
+        help="Guidance scale",
+    )
+    parser.add_argument(
+        "--seed",
+        type=int,
+        default=42,
+        help="Random seed",
+    )
+    parser.add_argument(
+        "--input-image",
+        type=Path,
+        help="Input image for I2V mode",
+    )
+    parser.add_argument(
+        "--preset",
+        choices=["base", "mid-stage2", "distilled"],
+        default="base",
+        help="Helios preset configuration",
+    )
+
+    args = parser.parse_args()
+
+    # Define preset configurations
+    presets = {
+        "base": None,  # No extra params for base model
+        "mid-stage2": {
+            "is_enable_stage2": True,
+            "pyramid_num_stages": 3,
+            "pyramid_num_inference_steps_list": [20, 20, 20],
+            "use_cfg_zero_star": True,
+            "use_zero_init": True,
+            "zero_steps": 1,
+        },
+        "distilled": {
+            "is_enable_stage2": True,
+            "pyramid_num_stages": 3,
+            "pyramid_num_inference_steps_list": [2, 2, 2],
+            "is_amplify_first_chunk": True,
+        },
+    }
+
+    extra_params = presets[args.preset]
+
+    print("=" * 50)
+    print("Helios Video Generation")
+    print("=" * 50)
+    print(f"API URL: {args.api_url}")
+    print(f"Model: {args.model}")
+    print(f"Preset: {args.preset}")
+    print(f"Prompt: {args.prompt}")
+    print(f"Size: {args.width}x{args.height}")
+    print(f"Frames: {args.num_frames}")
+    print(f"Guidance Scale: {args.guidance_scale}")
+    if extra_params:
+        print(f"Extra Params: {json.dumps(extra_params, indent=2)}")
+    print()
+
+    # Create video job
+    print("Creating video generation job...")
+    job = create_video_job(
+        api_url=args.api_url,
+        prompt=args.prompt,
+        model=args.model,
+        width=args.width,
+        height=args.height,
+        num_frames=args.num_frames,
+        guidance_scale=args.guidance_scale,
+        seed=args.seed,
+        extra_params=extra_params,
+        input_image=args.input_image,
+    )
+
+    video_id = job["id"]
+    print(f"Video job created: {video_id}")
+    print()
+
+    # Poll for completion
+    result = poll_video_status(args.api_url, video_id)
+
+    print()
+    print("=" * 50)
+    print("Generation Complete")
+    print("=" * 50)
+    print(f"Video ID: {result['id']}")
+    print(f"File: {result.get('file_name', 'N/A')}")
+    print(f"Inference Time: {result.get('inference_time_s', 'N/A')}s")
+    print()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/examples/online_serving/helios/run_helios_distilled.sh b/examples/online_serving/helios/run_helios_distilled.sh
new file mode 100644
index 000000000..15b6d8c30
--- /dev/null
+++ b/examples/online_serving/helios/run_helios_distilled.sh
@@ -0,0 +1,79 @@
+#!/bin/bash
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+# Helios-Distilled with DMD Example
+# Fast generation with Distribution Matching Distillation
+
+API_URL="${API_URL:-http://localhost:8000}"
+MODEL="${MODEL:-BestWishYsh/Helios-Distilled}"
+PROMPT="${PROMPT:-A serene lakeside sunrise with mist over the water.}"
+
+echo "==================================="
+echo "Helios-Distilled with DMD"
+echo "==================================="
+echo "API URL: $API_URL"
+echo "Model: $MODEL"
+echo "Prompt: $PROMPT"
+echo ""
+
+# Model-specific parameters for Helios-Distilled
+extra_params='{
+  "is_enable_stage2": true,
+  "pyramid_num_stages": 3,
+  "pyramid_num_inference_steps_list": [2, 2, 2],
+  "is_amplify_first_chunk": true
+}'
+
+echo "Model extra params: $extra_params"
+echo ""
+
+# Create video generation job
+echo "Creating video generation job..."
+RESPONSE=$(curl -s -X POST "$API_URL/v1/videos" \
+  -F "prompt=$PROMPT" \
+  -F "model=$MODEL" \
+  -F "width=640" \
+  -F "height=384" \
+  -F "guidance_scale=1.0" \
+  -F "seed=42" \
+  -F "extra_params=$extra_params")
+
+echo "Response: $RESPONSE"
+echo ""
+
+# Extract video ID
+VIDEO_ID=$(echo "$RESPONSE" | grep -o '"id":"[^"]*"' | cut -d'"' -f4)
+
+if [ -z "$VIDEO_ID" ]; then
+  echo "Error: Failed to create video job"
+  exit 1
+fi
+
+echo "Video job created: $VIDEO_ID"
+echo ""
+
+# Poll for completion
+echo "Polling for completion..."
+while true; do
+  STATUS_RESPONSE=$(curl -s "$API_URL/v1/videos/$VIDEO_ID")
+  STATUS=$(echo "$STATUS_RESPONSE" | grep -o '"status":"[^"]*"' | cut -d'"' -f4)
+  PROGRESS=$(echo "$STATUS_RESPONSE" | grep -o '"progress":[0-9]*' | cut -d':' -f2)
+
+  echo "Status: $STATUS, Progress: $PROGRESS%"
+
+  if [ "$STATUS" = "completed" ]; then
+    echo ""
+    echo "Video generation completed!"
+    echo "Full response:"
+    echo "$STATUS_RESPONSE" | jq '.'
+    break
+  elif [ "$STATUS" = "failed" ]; then
+    echo ""
+    echo "Video generation failed!"
+    echo "$STATUS_RESPONSE" | jq '.'
+    exit 1
+  fi
+
+  sleep 2
+done
diff --git a/examples/online_serving/helios/run_helios_mid_stage2.sh b/examples/online_serving/helios/run_helios_mid_stage2.sh
new file mode 100644
index 000000000..d5da9b22c
--- /dev/null
+++ b/examples/online_serving/helios/run_helios_mid_stage2.sh
@@ -0,0 +1,81 @@
+#!/bin/bash
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+# Helios-Mid with Stage 2 + CFG-Zero* Example
+# This demonstrates advanced generation with pyramid multi-stage denoising
+
+API_URL="${API_URL:-http://localhost:8000}"
+MODEL="${MODEL:-BestWishYsh/Helios-Mid}"
+PROMPT="${PROMPT:-A serene lakeside sunrise with mist over the water.}"
+
+echo "==================================="
+echo "Helios-Mid Stage 2 + CFG-Zero*"
+echo "==================================="
+echo "API URL: $API_URL"
+echo "Model: $MODEL"
+echo "Prompt: $PROMPT"
+echo ""
+
+# Model-specific parameters for Helios-Mid
+extra_params='{
+  "is_enable_stage2": true,
+  "pyramid_num_stages": 3,
+  "pyramid_num_inference_steps_list": [20, 20, 20],
+  "use_cfg_zero_star": true,
+  "use_zero_init": true,
+  "zero_steps": 1
+}'
+
+echo "Model extra params: $extra_params"
+echo ""
+
+# Create video generation job
+echo "Creating video generation job..."
+RESPONSE=$(curl -s -X POST "$API_URL/v1/videos" \
+  -F "prompt=$PROMPT" \
+  -F "model=$MODEL" \
+  -F "width=640" \
+  -F "height=384" \
+  -F "guidance_scale=5.0" \
+  -F "seed=42" \
+  -F "extra_params=$extra_params")
+
+echo "Response: $RESPONSE"
+echo ""
+
+# Extract video ID
+VIDEO_ID=$(echo "$RESPONSE" | grep -o '"id":"[^"]*"' | cut -d'"' -f4)
+
+if [ -z "$VIDEO_ID" ]; then
+  echo "Error: Failed to create video job"
+  exit 1
+fi
+
+echo "Video job created: $VIDEO_ID"
+echo ""
+
+# Poll for completion
+echo "Polling for completion..."
+while true; do
+  STATUS_RESPONSE=$(curl -s "$API_URL/v1/videos/$VIDEO_ID")
+  STATUS=$(echo "$STATUS_RESPONSE" | grep -o '"status":"[^"]*"' | cut -d'"' -f4)
+  PROGRESS=$(echo "$STATUS_RESPONSE" | grep -o '"progress":[0-9]*' | cut -d':' -f2)
+
+  echo "Status: $STATUS, Progress: $PROGRESS%"
+
+  if [ "$STATUS" = "completed" ]; then
+    echo ""
+    echo "Video generation completed!"
+    echo "Full response:"
+    echo "$STATUS_RESPONSE" | jq '.'
+    break
+  elif [ "$STATUS" = "failed" ]; then
+    echo ""
+    echo "Video generation failed!"
+    echo "$STATUS_RESPONSE" | jq '.'
+    exit 1
+  fi
+
+  sleep 2
+done
diff --git a/examples/online_serving/helios/run_helios_t2v.sh b/examples/online_serving/helios/run_helios_t2v.sh
new file mode 100644
index 000000000..e920fc872
--- /dev/null
+++ b/examples/online_serving/helios/run_helios_t2v.sh
@@ -0,0 +1,69 @@
+#!/bin/bash
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+# Helios Text-to-Video Generation Example
+# This script demonstrates how to use the /v1/videos API with Helios models
+
+API_URL="${API_URL:-http://localhost:8000}"
+MODEL="${MODEL:-BestWishYsh/Helios-Base}"
+PROMPT="${PROMPT:-A serene lakeside sunrise with mist over the water.}"
+
+echo "==================================="
+echo "Helios T2V Generation"
+echo "==================================="
+echo "API URL: $API_URL"
+echo "Model: $MODEL"
+echo "Prompt: $PROMPT"
+echo ""
+
+# Create video generation job
+echo "Creating video generation job..."
+RESPONSE=$(curl -s -X POST "$API_URL/v1/videos" \
+  -F "prompt=$PROMPT" \
+  -F "model=$MODEL" \
+  -F "width=640" \
+  -F "height=384" \
+  -F "num_frames=99" \
+  -F "num_inference_steps=50" \
+  -F "guidance_scale=5.0" \
+  -F "seed=42")
+
+echo "Response: $RESPONSE"
+echo ""
+
+# Extract video ID
+VIDEO_ID=$(echo "$RESPONSE" | grep -o '"id":"[^"]*"' | cut -d'"' -f4)
+
+if [ -z "$VIDEO_ID" ]; then
+  echo "Error: Failed to create video job"
+  exit 1
+fi
+
+echo "Video job created: $VIDEO_ID"
+echo ""
+
+# Poll for completion
+echo "Polling for completion..."
+while true; do
+  STATUS_RESPONSE=$(curl -s "$API_URL/v1/videos/$VIDEO_ID")
+  STATUS=$(echo "$STATUS_RESPONSE" | grep -o '"status":"[^"]*"' | cut -d'"' -f4)
+  PROGRESS=$(echo "$STATUS_RESPONSE" | grep -o '"progress":[0-9]*' | cut -d':' -f2)
+
+  echo "Status: $STATUS, Progress: $PROGRESS%"
+
+  if [ "$STATUS" = "completed" ]; then
+    echo ""
+    echo "Video generation completed!"
+    echo "Full response:"
+    echo "$STATUS_RESPONSE" | jq '.'
+    break
+  elif [ "$STATUS" = "failed" ]; then
+    echo ""
+    echo "Video generation failed!"
+    echo "$STATUS_RESPONSE" | jq '.'
+    exit 1
+  fi
+
+  sleep 2
+done
diff --git a/tests/entrypoints/openai_api/test_video_server.py b/tests/entrypoints/openai_api/test_video_server.py
index f8a8a1e4b..f8d68d95a 100644
--- a/tests/entrypoints/openai_api/test_video_server.py
+++ b/tests/entrypoints/openai_api/test_video_server.py
@@ -638,3 +638,100 @@ def test_video_response_file_extension_is_robust():
             media_type="application/x-custom-video",
         )
         _ = unknown.file_extension
+
+
+def test_extra_params_merged_into_extra_args(test_client, mocker: MockerFixture):
+    """extra_params JSON object is merged into sampling_params.extra_args."""
+    mocker.patch(
+        "vllm_omni.entrypoints.openai.serving_video.encode_video_base64",
+        return_value="Zg==",
+    )
+    extra_params = {
+        "is_enable_stage2": True,
+        "pyramid_num_stages": 3,
+        "pyramid_num_inference_steps_list": [20, 20, 20],
+        "use_cfg_zero_star": True,
+    }
+    response = test_client.post(
+        "/v1/videos",
+        data={
+            "prompt": "A rocket launching.",
+            "extra_params": json.dumps(extra_params),
+        },
+    )
+
+    assert response.status_code == 200
+    video_id = response.json()["id"]
+    _wait_for_status(test_client, video_id, VideoGenerationStatus.COMPLETED.value)
+    engine = test_client.app.state.openai_serving_video._engine_client
+    captured = engine.captured_sampling_params_list[0]
+    assert captured.extra_args["is_enable_stage2"] is True
+    assert captured.extra_args["pyramid_num_stages"] == 3
+    assert captured.extra_args["pyramid_num_inference_steps_list"] == [20, 20, 20]
+    assert captured.extra_args["use_cfg_zero_star"] is True
+
+
+def test_extra_params_none_by_default(test_client, mocker: MockerFixture):
+    """When extra_params is omitted, extra_args stays empty."""
+    mocker.patch(
+        "vllm_omni.entrypoints.openai.serving_video.encode_video_base64",
+        return_value="Zg==",
+    )
+    response = test_client.post(
+        "/v1/videos",
+        data={"prompt": "A calm river."},
+    )
+
+    assert response.status_code == 200
+    video_id = response.json()["id"]
+    _wait_for_status(test_client, video_id, VideoGenerationStatus.COMPLETED.value)
+    engine = test_client.app.state.openai_serving_video._engine_client
+    captured = engine.captured_sampling_params_list[0]
+    assert "is_enable_stage2" not in captured.extra_args
+
+
+def test_extra_params_invalid_json(test_client):
+    """Malformed JSON for extra_params returns 400."""
+    response = test_client.post(
+        "/v1/videos",
+        data={
+            "prompt": "A forest.",
+            "extra_params": "{not valid json}",
+        },
+    )
+    assert response.status_code == 400
+
+    """extra_params must be a JSON object, not an array."""
+    response = test_client.post(
+        "/v1/videos",
+        data={
+            "prompt": "A desert.",
+            "extra_params": json.dumps([1, 2, 3]),
+        },
+    )
+    assert response.status_code == 400
+
+
+def test_extra_params_merged_with_existing_extra_args(test_client, mocker: MockerFixture):
+    """extra_params is merged on top of existing extra_args (e.g. flow_shift)."""
+    mocker.patch(
+        "vllm_omni.entrypoints.openai.serving_video.encode_video_base64",
+        return_value="Zg==",
+    )
+    response = test_client.post(
+        "/v1/videos",
+        data={
+            "prompt": "A mountain peak.",
+            "flow_shift": "0.5",
+            "extra_params": json.dumps({"use_zero_init": True, "zero_steps": 2}),
+        },
+    )
+
+    assert response.status_code == 200
+    video_id = response.json()["id"]
+    _wait_for_status(test_client, video_id, VideoGenerationStatus.COMPLETED.value)
+    engine = test_client.app.state.openai_serving_video._engine_client
+    captured = engine.captured_sampling_params_list[0]
+    assert captured.extra_args["flow_shift"] == 0.5
+    assert captured.extra_args["use_zero_init"] is True
+    assert captured.extra_args["zero_steps"] == 2
diff --git a/vllm_omni/entrypoints/openai/api_server.py b/vllm_omni/entrypoints/openai/api_server.py
index ce387d404..82f05c53c 100644
--- a/vllm_omni/entrypoints/openai/api_server.py
+++ b/vllm_omni/entrypoints/openai/api_server.py
@@ -1714,16 +1714,22 @@ def _resolve_video_runtime_context(raw_request: Request) -> tuple[str | None, li
     return app_model_name, app_stage_configs
 
 
-def _parse_form_json(value: str | None) -> Any:
+def _parse_form_json(value: str | None, expected_type: type | None = None) -> Any:
     if value is None or value == "":
         return None
     try:
-        return json.loads(value)
+        parsed = json.loads(value)
     except json.JSONDecodeError as exc:
         raise HTTPException(
             status_code=HTTPStatus.BAD_REQUEST.value,
             detail="Invalid JSON in form field.",
         ) from exc
+    if expected_type is not None and not isinstance(parsed, expected_type):
+        raise HTTPException(
+            status_code=HTTPStatus.BAD_REQUEST.value,
+            detail=f"Invalid JSON in form field: expected {expected_type.__name__}, got {type(parsed).__name__}.",
+        )
+    return parsed
 
 
 def video_response_from_request(model_name: str, req: VideoGenerationRequest) -> VideoResponse:
@@ -1844,6 +1850,7 @@ async def create_video(
     seed: int | None = Form(default=None),
     negative_prompt: str | None = Form(default=None),
     lora: str | None = Form(default=None),
+    extra_params: str | None = Form(default=None),
 ) -> VideoResponse:
     """Create an asynchronous video generation job.
 
@@ -1874,6 +1881,7 @@ async def create_video(
         seed: Optional random seed override.
         negative_prompt: Optional negative prompt.
         lora: Optional JSON-encoded per-request LoRA configuration.
+        extra_params: Optional model-specific parameters passed directly to the model's extra_args.
 
     Returns:
         A queued ``VideoResponse`` that includes the generated job identifier
@@ -1910,7 +1918,8 @@ async def create_video(
         "true_cfg_scale": true_cfg_scale,
         "seed": seed,
         "negative_prompt": negative_prompt,
-        "lora": _parse_form_json(lora),
+        "lora": _parse_form_json(lora, expected_type=dict),
+        "extra_params": _parse_form_json(extra_params, expected_type=dict),
     }
 
     request_data = {k: v for k, v in request_data.items() if v is not None}
diff --git a/vllm_omni/entrypoints/openai/protocol/videos.py b/vllm_omni/entrypoints/openai/protocol/videos.py
index 1da6bdb08..e180bef22 100644
--- a/vllm_omni/entrypoints/openai/protocol/videos.py
+++ b/vllm_omni/entrypoints/openai/protocol/videos.py
@@ -161,6 +161,12 @@ class VideoGenerationRequest(BaseModel):
         ),
     )
 
+    # Generic model-specific parameters
+    extra_params: dict[str, Any] | None = Field(
+        default=None,
+        description=("Optional model-specific parameters passed directly to the model's extra_args. "),
+    )
+
     def resolve_video_params(self) -> VideoParams:
         vp = VideoParams(width=self.width, height=self.height, fps=self.fps, num_frames=self.num_frames)
 
diff --git a/vllm_omni/entrypoints/openai/serving_video.py b/vllm_omni/entrypoints/openai/serving_video.py
index 48ffd4956..5ccc7c3d2 100644
--- a/vllm_omni/entrypoints/openai/serving_video.py
+++ b/vllm_omni/entrypoints/openai/serving_video.py
@@ -122,6 +122,17 @@ class OmniOpenAIServingVideo:
         if request.flow_shift is not None:
             gen_params.extra_args["flow_shift"] = request.flow_shift
 
+        # Apply model-specific extra parameters
+        if request.extra_params is not None:
+            if not isinstance(request.extra_params, dict):
+                raise HTTPException(
+                    status_code=HTTPStatus.BAD_REQUEST.value,
+                    detail="extra_params must be a JSON object/dict.",
+                )
+            # Merge extra_params into extra_args
+            gen_params.extra_args.update(request.extra_params)
+            logger.info("Applied extra_params: %s", request.extra_params)
+
         self._apply_lora(request.lora, gen_params)
 
         logger.info(