diff --git a/comfy_api_nodes/apis/bytedance_llm.py b/comfy_api_nodes/apis/bytedance_llm.py
new file mode 100644
index 000000000..654c875fc
--- /dev/null
+++ b/comfy_api_nodes/apis/bytedance_llm.py
@@ -0,0 +1,101 @@
+"""Pydantic models for BytePlus ModelArk Responses API.
+
+See: https://docs.byteplus.com/en/docs/ModelArk/1585128 (request)
+     https://docs.byteplus.com/en/docs/ModelArk/1783703 (response)
+"""
+
+from typing import Literal
+
+from pydantic import BaseModel, Field
+
+
+class BytePlusInputText(BaseModel):
+    type: Literal["input_text"] = "input_text"
+    text: str = Field(...)
+
+
+class BytePlusInputImage(BaseModel):
+    type: Literal["input_image"] = "input_image"
+    image_url: str = Field(..., description="Image URL or `data:image/...;base64,...` payload")
+    detail: str = Field("auto", description="One of high, low, auto")
+
+
+class BytePlusInputVideo(BaseModel):
+    type: Literal["input_video"] = "input_video"
+    video_url: str = Field(..., description="Video URL or `data:video/...;base64,...` payload")
+    fps: float | None = Field(None, ge=0.2, le=5.0)
+
+
+BytePlusMessageContent = BytePlusInputText | BytePlusInputImage | BytePlusInputVideo
+
+
+class BytePlusInputMessage(BaseModel):
+    type: Literal["message"] = "message"
+    role: str = Field(..., description="One of user, system, assistant, developer")
+    content: list[BytePlusMessageContent] = Field(...)
+
+
+class BytePlusResponseCreateRequest(BaseModel):
+    model: str = Field(...)
+    input: list[BytePlusInputMessage] = Field(...)
+    instructions: str | None = Field(None)
+    max_output_tokens: int | None = Field(None, ge=1)
+    temperature: float | None = Field(None, ge=0.0, le=2.0)
+    store: bool | None = Field(False)
+    stream: bool | None = Field(False)
+
+
+class BytePlusOutputText(BaseModel):
+    type: Literal["output_text"] = "output_text"
+    text: str = Field(...)
+
+
+class BytePlusOutputRefusal(BaseModel):
+    type: Literal["refusal"] = "refusal"
+    refusal: str = Field(...)
+
+
+class BytePlusOutputContent(BaseModel):
+    type: str = Field(...)
+    text: str | None = Field(None)
+    refusal: str | None = Field(None)
+
+
+class BytePlusOutputMessage(BaseModel):
+    type: str = Field(...)
+    id: str | None = Field(None)
+    role: str | None = Field(None)
+    status: str | None = Field(None)
+    content: list[BytePlusOutputContent] | None = Field(None)
+
+
+class BytePlusInputTokensDetails(BaseModel):
+    cached_tokens: int | None = Field(None)
+
+
+class BytePlusOutputTokensDetails(BaseModel):
+    reasoning_tokens: int | None = Field(None)
+
+
+class BytePlusResponseUsage(BaseModel):
+    input_tokens: int | None = Field(None)
+    output_tokens: int | None = Field(None)
+    total_tokens: int | None = Field(None)
+    input_tokens_details: BytePlusInputTokensDetails | None = Field(None)
+    output_tokens_details: BytePlusOutputTokensDetails | None = Field(None)
+
+
+class BytePlusResponseError(BaseModel):
+    code: str = Field(...)
+    message: str = Field(...)
+
+
+class BytePlusResponseObject(BaseModel):
+    id: str | None = Field(None)
+    object: str | None = Field(None)
+    created_at: int | None = Field(None)
+    model: str | None = Field(None)
+    status: str | None = Field(None)
+    error: BytePlusResponseError | None = Field(None)
+    output: list[BytePlusOutputMessage] | None = Field(None)
+    usage: BytePlusResponseUsage | None = Field(None)
diff --git a/comfy_api_nodes/nodes_bytedance_llm.py b/comfy_api_nodes/nodes_bytedance_llm.py
new file mode 100644
index 000000000..fa7fe370a
--- /dev/null
+++ b/comfy_api_nodes/nodes_bytedance_llm.py
@@ -0,0 +1,271 @@
+"""API Nodes for ByteDance Seed LLM via the BytePlus ModelArk Responses API.
+
+See: https://docs.byteplus.com/en/docs/ModelArk/1585128
+"""
+
+from typing_extensions import override
+
+from comfy_api.latest import IO, ComfyExtension, Input
+from comfy_api_nodes.apis.bytedance_llm import (
+    BytePlusInputImage,
+    BytePlusInputMessage,
+    BytePlusInputText,
+    BytePlusInputVideo,
+    BytePlusMessageContent,
+    BytePlusResponseCreateRequest,
+    BytePlusResponseObject,
+)
+from comfy_api_nodes.util import (
+    ApiEndpoint,
+    get_number_of_images,
+    sync_op,
+    upload_images_to_comfyapi,
+    upload_video_to_comfyapi,
+    validate_string,
+)
+
+BYTEPLUS_RESPONSES_ENDPOINT = "/proxy/byteplus/api/v3/responses"
+SEED_MAX_IMAGES = 20
+SEED_MAX_VIDEOS = 4
+
+SEED_MODELS: dict[str, str] = {
+    "Seed 2.0 Pro": "seed-2-0-pro-260328",
+    "Seed 2.0 Lite": "seed-2-0-lite-260228",
+    "Seed 2.0 Mini": "seed-2-0-mini-260215",
+}
+
+# USD per 1M tokens: (input, cache_hit_input, output)
+_SEED_PRICES_PER_MILLION: dict[str, tuple[float, float, float]] = {
+    "seed-2-0-pro-260328": (0.50, 0.10, 3.00),
+    "seed-2-0-lite-260228": (0.25, 0.05, 2.00),
+    "seed-2-0-mini-260215": (0.10, 0.02, 0.40),
+}
+
+
+def _seed_model_inputs(max_images: int = SEED_MAX_IMAGES, max_videos: int = SEED_MAX_VIDEOS):
+    return [
+        IO.Autogrow.Input(
+            "images",
+            template=IO.Autogrow.TemplateNames(
+                IO.Image.Input("image"),
+                names=[f"image_{i}" for i in range(1, max_images + 1)],
+                min=0,
+            ),
+            tooltip=f"Optional image(s) to use as context for the model. Up to {max_images} images.",
+        ),
+        IO.Autogrow.Input(
+            "videos",
+            template=IO.Autogrow.TemplateNames(
+                IO.Video.Input("video"),
+                names=[f"video_{i}" for i in range(1, max_videos + 1)],
+                min=0,
+            ),
+            tooltip=f"Optional video(s) to use as context for the model. Up to {max_videos} videos.",
+        ),
+        IO.Float.Input(
+            "temperature",
+            default=1.0,
+            min=0.0,
+            max=2.0,
+            step=0.01,
+            tooltip="Controls randomness. 0.0 is deterministic, higher values are more random.",
+            advanced=True,
+        ),
+    ]
+
+
+def _calculate_price(model_id: str, response: BytePlusResponseObject) -> float | None:
+    """Compute approximate USD price from response usage."""
+    if not response.usage:
+        return None
+    rates = _SEED_PRICES_PER_MILLION.get(model_id)
+    if rates is None:
+        return None
+    input_rate, cache_hit_rate, output_rate = rates
+    input_tokens = response.usage.input_tokens or 0
+    output_tokens = response.usage.output_tokens or 0
+    cached = 0
+    if response.usage.input_tokens_details:
+        cached = response.usage.input_tokens_details.cached_tokens or 0
+    fresh_input = max(0, input_tokens - cached)
+    total = fresh_input * input_rate + cached * cache_hit_rate + output_tokens * output_rate
+    return total / 1_000_000.0
+
+
+def _get_text_from_response(response: BytePlusResponseObject) -> str:
+    """Extract concatenated text from all assistant message output_text blocks."""
+    if not response.output:
+        return ""
+    chunks: list[str] = []
+    for item in response.output:
+        if item.type != "message" or not item.content:
+            continue
+        for block in item.content:
+            if block.type == "output_text" and block.text:
+                chunks.append(block.text)
+            elif block.type == "refusal" and block.refusal:
+                raise ValueError(f"Model refused to respond: {block.refusal}")
+    return "\n".join(chunks)
+
+
+async def _build_image_content_blocks(
+    cls: type[IO.ComfyNode],
+    image_tensors: list[Input.Image],
+) -> list[BytePlusInputImage]:
+    urls = await upload_images_to_comfyapi(
+        cls,
+        image_tensors,
+        max_images=SEED_MAX_IMAGES,
+        wait_label="Uploading reference images",
+    )
+    return [BytePlusInputImage(image_url=url) for url in urls]
+
+
+async def _build_video_content_blocks(
+    cls: type[IO.ComfyNode],
+    videos: list[Input.Video],
+) -> list[BytePlusInputVideo]:
+    blocks: list[BytePlusInputVideo] = []
+    total = len(videos)
+    for idx, video in enumerate(videos):
+        label = "Uploading reference video"
+        if total > 1:
+            label = f"{label} ({idx + 1}/{total})"
+        url = await upload_video_to_comfyapi(cls, video, wait_label=label)
+        blocks.append(BytePlusInputVideo(video_url=url))
+    return blocks
+
+
+class ByteDanceSeedNode(IO.ComfyNode):
+    """Generate text responses from a ByteDance Seed 2.0 model."""
+
+    @classmethod
+    def define_schema(cls):
+        return IO.Schema(
+            node_id="ByteDanceSeedNode",
+            display_name="ByteDance Seed",
+            category="api node/text/ByteDance",
+            essentials_category="Text Generation",
+            description="Generate text responses with ByteDance's Seed 2.0 models. "
+            "Provide a text prompt and optionally one or more images or videos for multimodal context.",
+            inputs=[
+                IO.String.Input(
+                    "prompt",
+                    multiline=True,
+                    default="",
+                    tooltip="Text input to the model.",
+                ),
+                IO.DynamicCombo.Input(
+                    "model",
+                    options=[IO.DynamicCombo.Option(label, _seed_model_inputs()) for label in SEED_MODELS],
+                    tooltip="The Seed model used to generate the response.",
+                ),
+                IO.Int.Input(
+                    "seed",
+                    default=0,
+                    min=0,
+                    max=2147483647,
+                    control_after_generate=True,
+                    tooltip="Seed controls whether the node should re-run; "
+                    "results are non-deterministic regardless of seed.",
+                ),
+                IO.String.Input(
+                    "system_prompt",
+                    multiline=True,
+                    default="",
+                    optional=True,
+                    advanced=True,
+                    tooltip="Foundational instructions that dictate the model's behavior.",
+                ),
+            ],
+            outputs=[IO.String.Output()],
+            hidden=[
+                IO.Hidden.auth_token_comfy_org,
+                IO.Hidden.api_key_comfy_org,
+                IO.Hidden.unique_id,
+            ],
+            is_api_node=True,
+            price_badge=IO.PriceBadge(
+                depends_on=IO.PriceBadgeDepends(widgets=["model"]),
+                expr="""
+                (
+                  $m := widgets.model;
+                  $contains($m, "mini") ? {
+                    "type": "list_usd",
+                    "usd": [0.00025, 0.0009],
+                    "format": { "approximate": true, "separator": "-", "suffix": " per 1K tokens" }
+                  }
+                  : $contains($m, "lite") ? {
+                    "type": "list_usd",
+                    "usd": [0.0003, 0.002],
+                    "format": { "approximate": true, "separator": "-", "suffix": " per 1K tokens" }
+                  }
+                  : $contains($m, "pro") ? {
+                    "type": "list_usd",
+                    "usd": [0.0005, 0.003],
+                    "format": { "approximate": true, "separator": "-", "suffix": " per 1K tokens" }
+                  }
+                  : {"type":"text", "text":"Token-based"}
+                )
+                """,
+            ),
+        )
+
+    @classmethod
+    async def execute(
+        cls,
+        prompt: str,
+        model: dict,
+        seed: int,
+        system_prompt: str = "",
+    ) -> IO.NodeOutput:
+        validate_string(prompt, strip_whitespace=True, min_length=1)
+        model_label = model["model"]
+        temperature = model["temperature"]
+        model_id = SEED_MODELS[model_label]
+
+        image_tensors: list[Input.Image] = [t for t in (model.get("images") or {}).values() if t is not None]
+        if sum(get_number_of_images(t) for t in image_tensors) > SEED_MAX_IMAGES:
+            raise ValueError(f"Up to {SEED_MAX_IMAGES} images are supported per request.")
+
+        video_inputs: list[Input.Video] = [v for v in (model.get("videos") or {}).values() if v is not None]
+        if len(video_inputs) > SEED_MAX_VIDEOS:
+            raise ValueError(f"Up to {SEED_MAX_VIDEOS} videos are supported per request.")
+
+        content: list[BytePlusMessageContent] = []
+        if image_tensors:
+            content.extend(await _build_image_content_blocks(cls, image_tensors))
+        if video_inputs:
+            content.extend(await _build_video_content_blocks(cls, video_inputs))
+        content.append(BytePlusInputText(text=prompt))
+
+        response = await sync_op(
+            cls,
+            ApiEndpoint(path=BYTEPLUS_RESPONSES_ENDPOINT, method="POST"),
+            response_model=BytePlusResponseObject,
+            data=BytePlusResponseCreateRequest(
+                model=model_id,
+                input=[BytePlusInputMessage(role="user", content=content)],
+                instructions=system_prompt or None,
+                temperature=temperature,
+                store=False,
+                stream=False,
+            ),
+            price_extractor=lambda r: _calculate_price(model_id, r),
+        )
+        if response.error:
+            raise ValueError(f"Seed API error ({response.error.code}): {response.error.message}")
+        result = _get_text_from_response(response)
+        if not result:
+            raise ValueError("Empty response from Seed model.")
+        return IO.NodeOutput(result)
+
+
+class ByteDanceLLMExtension(ComfyExtension):
+    @override
+    async def get_node_list(self) -> list[type[IO.ComfyNode]]:
+        return [ByteDanceSeedNode]
+
+
+async def comfy_entrypoint() -> ByteDanceLLMExtension:
+    return ByteDanceLLMExtension()