> For the complete documentation index, see [llms.txt](https://docs.roboflow.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.roboflow.com/workflows/blocks/blocks/run-a-model/qwen3-5-api.md).
# Qwen 3.5 API
{% hint style="warning" %}
**Deprecated**
Use the unified Qwen-VL block (`roboflow_core/qwen_vlm@v1`), which combines all Qwen variants (native + OpenRouter) with managed-key passthrough and privacy controls.
{% endhint %}
Ask a question to Qwen 3.5 vision-language models served via OpenRouter.
You can specify arbitrary text prompts or predefined ones, the block supports the following types of prompt:
* **Open Prompt** (`unconstrained`) - Use any prompt to generate a raw response
* **Text Recognition (OCR)** (`ocr`) - Model recognizes text in the image
* **Visual Question Answering** (`visual-question-answering`) - Model answers the question you submit in the prompt
* **Captioning (short)** (`caption`) - Model provides a short description of the image
* **Captioning** (`detailed-caption`) - Model provides a long description of the image
* **Single-Label Classification** (`classification`) - Model classifies the image content as one of the provided classes
* **Multi-Label Classification** (`multi-label-classification`) - Model classifies the image content as one or more of the provided classes
* **Unprompted Object Detection** (`object-detection`) - Model detects and returns the bounding boxes for prominent objects in the image
* **Structured Output Generation** (`structured-answering`) - Model returns a JSON response with the specified fields
#### 🛠️ API providers and model variants
Qwen 3.5 is exposed via [OpenRouter API](https://openrouter.ai/) and we require passing an [OpenRouter API Key](https://openrouter.ai/docs/api-keys) to run.
Pick a specific model version from the `model_version` dropdown - new Qwen 3.5 releases will be added to this list as they become available on OpenRouter.
{% hint style="warning" %}
**API Usage Charges**
OpenRouter is an external third party providing access to the model and incurring charges on the usage. Please check pricing on [openrouter.ai](https://openrouter.ai/) before use.
{% endhint %}
#### 💡 Further reading and Acceptable Use Policy
{% hint style="warning" %}
**Model license**
Check the [Qwen license terms](https://huggingface.co/Qwen) before use.
{% endhint %}
### Type identifier
Use the following identifier in step `"type"` field: `roboflow_core/qwen3_5_openrouter@v1` to add the block as a step in your workflow.
### Properties
| **Name** | **Type** | **Description** | Refs |
| ------------------------- | ---------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ---- |
| `name` | `str` | Enter a unique identifier for this step.. | ❌ |
| `task_type` | `str` | Task type to be performed by model. Value determines required parameters and output response.. | ❌ |
| `prompt` | `str` | Text prompt to the Qwen 3.5 model. | ✅ |
| `output_structure` | `Dict[str, str]` | Dictionary with structure of expected JSON response. | ❌ |
| `classes` | `List[str]` | List of classes to be used. | ✅ |
| `api_key` | `str` | Your OpenRouter API key. | ✅ |
| `model_version` | `str` | Model to be used. | ✅ |
| `max_tokens` | `int` | Maximum number of tokens the model can generate in it's response.. | ❌ |
| `temperature` | `float` | Temperature to sample from the model - value in range 0.0-2.0, the higher - the more random / "creative" the generations are.. | ✅ |
| `max_concurrent_requests` | `int` | Number of concurrent requests that can be executed by block when batch of input images provided. If not given - block defaults to value configured globally in Workflows Execution Engine. Please restrict if you hit limits.. | ❌ |
The **Refs** column marks possibility to parametrise the property with dynamic values available in `workflow` runtime. See *Bindings* for more info.
### :material-shield-half-full:{ style="color: #5e6c75" } Runtime compatibility
:material-cloud-off-outline:{ style="color: #546e7a" } `requires_internet` - air-gapped / offline deployments : This block depends on a service that is not reachable from fully offline / air-gapped deployments.
### Input and Output Bindings
The available connections depend on its binding kinds. Check what binding kinds `Qwen 3.5 API` in version `v1` has.
Input and output bindings
* input
* `images` ([*`image`*](https://inference.roboflow.com/workflows/kinds/image/)): The image to infer on..
* `prompt` ([*`string`*](https://inference.roboflow.com/workflows/kinds/string/)): Text prompt to the Qwen 3.5 model.
* `classes` ([*`list_of_values`*](https://inference.roboflow.com/workflows/kinds/list_of_values/)): List of classes to be used.
* `api_key` (*Union\[*[*`secret`*](https://inference.roboflow.com/workflows/kinds/secret/)*,* [*`string`*](https://inference.roboflow.com/workflows/kinds/string/)*]*): Your OpenRouter API key.
* `model_version` ([*`string`*](https://inference.roboflow.com/workflows/kinds/string/)): Model to be used.
* `temperature` ([*`float`*](https://inference.roboflow.com/workflows/kinds/float/)): Temperature to sample from the model - value in range 0.0-2.0, the higher - the more random / "creative" the generations are..
* output
* `output` (*Union\[*[*`string`*](https://inference.roboflow.com/workflows/kinds/string/)*,* [*`language_model_output`*](https://inference.roboflow.com/workflows/kinds/language_model_output/)*]*): String value if `string` or LLM / VLM output if `language_model_output`.
* `classes` ([`list_of_values`](https://inference.roboflow.com/workflows/kinds/list_of_values/)): List of values of any type.
Example JSON definition
```json
{
"name": "",
"type": "roboflow_core/qwen3_5_openrouter@v1",
"images": "$inputs.image",
"task_type": "",
"prompt": "my prompt",
"output_structure": {
"my_key": "description"
},
"classes": [
"class-a",
"class-b"
],
"api_key": "xxx-xxx",
"model_version": "Qwen 3.5 27B - OpenRouter",
"max_tokens": "",
"temperature": "",
"max_concurrent_requests": ""
}
```