# Moondream3 Preview [Caption] API

> Sumusulat ng caption para sa larawan sa maikli, normal o mahabang haba

Tumatanggap ng larawan mula sa `image_url` at nagbabalik ng caption na teksto. Pinipili ng opsyong `length` ang short, normal o long, na may normal bilang default. Kinokontrol ng opsyonal na `temperature` at `top_p`, na parehong mula 0 hanggang 1, ang sampling. Kasama sa output ang caption, dahilan ng pagtatapos, at impormasyon sa paggamit.

- Model id: `moondream3-preview/caption`
- Made by: Moondream
- Category: Vision
- Output: text
- Estimated price per run: $0.002 / run (cheapest run $0.002 (2 API credits))
- Run: `POST https://api.doitong.com/v1/run/moondream3-preview/caption`
- Quote: `POST https://api.doitong.com/v1/quote/moondream3-preview/caption`
- Docs page: https://doitong.com/fil/developers/models/moondream3-preview/caption

## Pricing

Price: **$0.002 / run**. Estimated from the typical cost of one run. The quote is exactly what the run charges.

The full example input below costs $0.002 = 2 API credits (1 request × 2 API credits).

Prices are the upstream price in USD, paid from the API balance in API credits (1000 API credits = 1 USD). `POST https://api.doitong.com/v1/quote/moondream3-preview/caption` with the same JSON body returns the exact price for that input; the quote is exactly what a run charges. Invalid input is never charged and failed or canceled requests are refunded automatically.

## Input parameters

Send either the canonical name or the native field name (not both). Canonical names are the same across models.

| Parameter | Canonical name | Type | Required | Default | Allowed values / range | Description |
|---|---|---|---|---|---|---|
| `image_url` | `image` | string (image URL) | yes |  |  | URL na tumutukoy sa larawang ipoproseso. |
| `length` |  | enum (string) | no | `normal` | `short`, `normal`, `long` | Ninanais na haba ng nabuong caption. |
| `temperature` |  | number \| null | no |  | 0 – 1 | Sampling temperature mula 0 hanggang 1; default na 0 kapag hindi ibinigay. Ang mas mataas na value gaya ng 0.8 ay nagpapataas ng randomness, habang ang mas mababang value gaya ng 0.2 ay gumagawa ng mas nakatuon at deterministic na output. |
| `top_p` |  | number \| null | no |  | 0 – 1 | Probability mass para sa nucleus sampling, mula 0 hanggang 1. |

File parameters (`image`) take a public `https://` URL, a `data:` URI up to 10 MB, or the `file_url` of an upload from `POST /files`.

## Example input

Required parameters only:

```json
{
  "image": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
}
```

A fuller example:

```json
{
  "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
}
```

## Run it

Set `DOITONG_API_KEY` to a key from https://doitong.com/developers/dashboard#keys. `?wait=20` returns the finished request in the same call when it is ready within 20 seconds; otherwise poll `GET /requests/{id}` (it also accepts `?wait=`), or pass `webhook_url`.

### curl

```bash
# Run the model; wait up to 20 s for the finished result in the same call
curl -X POST "https://api.doitong.com/v1/run/moondream3-preview/caption?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
  }'

# Still "queued" or "running"? Poll with the id from the response:
curl "https://api.doitong.com/v1/requests/REQUEST_ID?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY"
```

### JavaScript

```javascript
const API = "https://api.doitong.com/v1";
const headers = {
  "Authorization": "Bearer " + process.env.DOITONG_API_KEY,
  "Content-Type": "application/json",
};

// Run the model; wait up to 20 s for the finished result in the same call
let res = await fetch(API + "/run/moondream3-preview/caption?wait=20", {
  method: "POST",
  headers,
  body: JSON.stringify({
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
  }),
});
let request = await res.json();
if (!res.ok) throw new Error(request.error.code + ": " + request.error.message);

// Not finished yet: long-poll until it is
while (request.status === "queued" || request.status === "running") {
  res = await fetch(API + "/requests/" + request.id + "?wait=20", { headers });
  request = await res.json();
}
if (request.status !== "succeeded") throw new Error(JSON.stringify(request.error));
console.log(request.outputs.map((o) => o.url), request.cost.credits + " API credits ($" + request.cost.usd + ")");
```

### Python

```python
import os
import requests

API = "https://api.doitong.com/v1"
headers = {"Authorization": "Bearer " + os.environ["DOITONG_API_KEY"]}

payload = {
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg",
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/moondream3-preview/caption", params={"wait": 20}, json=payload, headers=headers)
request = r.json()
if not r.ok:
    raise RuntimeError(request["error"]["code"] + ": " + request["error"]["message"])

# Not finished yet: long-poll until it is
while request["status"] in ("queued", "running"):
    request = requests.get(API + "/requests/" + request["id"], params={"wait": 20}, headers=headers).json()
if request["status"] != "succeeded":
    raise RuntimeError(request["error"])
print([o["url"] for o in request["outputs"]], request["cost"]["credits"], "API credits", "$" + request["cost"]["usd"])
```

### MCP

The MCP server at `https://api.doitong.com/v1/mcp` exposes the tools `search_models`, `get_model`, `quote`, `run`, `get_request`, `cancel_request`, `list_requests`, `create_upload` and `get_account`. A `run` call for this model:

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "run",
    "arguments": {
      "model_id": "moondream3-preview/caption",
      "input": {
        "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
      },
      "wait_seconds": 20
    }
  }
}
```

## Response

Every call returns a request object. `status` is one of `queued`, `running`, `succeeded`, `failed`, `canceled`. `outputs` lists the generated files with URLs on our storage (kept forever, or 7 days with `?storage=temporary`; `storage` says which); `output` is the model's own result object with the same URLs.

```json
{
  "id": "req_8k2m4q7x1z9c3v5b6n0p2r4t",
  "object": "request",
  "model": "moondream3-preview/caption",
  "status": "succeeded",
  "created_at": "2026-10-20T12:00:00Z",
  "started_at": "2026-10-20T12:00:02Z",
  "completed_at": "2026-10-20T12:00:09Z",
  "queue_position": null,
  "cost": {
    "credits": 2,
    "usd": "0.002",
    "charged": 2,
    "refunded": 0
  },
  "input": {
    "image_url": "https://content.doitong.com/images/showcase/v3/gen_fox_cartoon.jpg"
  },
  "output": {
    "finish_reason": "stop",
    "usage_info": {
      "input_tokens": 1,
      "output_tokens": 1,
      "prefill_time_ms": 1.0,
      "decode_time_ms": 1.0,
      "ttft_ms": 1.0
    },
    "output": "A hedgehog is captured in a close-up shot, focusing on its face and nose. The hedgehog's spines are visible along its back, and its nose is dark and wet-looking. A gold ring with a small diamond is positioned on the grass in front of the hedgehog, partially obscured by its nose. The background is a blurred green grassy field, with small white flowers scattered throughout the grass."
  },
  "outputs": [
    {
      "type": "file",
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.jpeg",
      "content_type": "image/jpeg",
      "file_size": 1843200,
      "stored": true
    }
  ],
  "error": null,
  "metrics": {
    "inference_seconds": 6.8
  },
  "urls": {
    "self": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
```

### Output fields (`output`)

| Field | Type | Description |
|---|---|---|
| `finish_reason` | string | Dahilan kung bakit natapos ang pagbuo ng output. |
| `usage_info` | object {input_tokens, output_tokens, prefill_time_ms, decode_time_ms, ttft_ms} | Mga detalye ng paggamit ng kahilingan. |
| `output` | string | Caption na binuo upang ilarawan ang larawan. |

## Related models

- [Moondream3 Preview \[Segment\]](https://doitong.com/developers/models/moondream3-preview/segment.md) (`moondream3-preview/segment`): $0.003 / run
- [Moondream 3 Preview \[Query\]](https://doitong.com/developers/models/moondream3-preview/query.md) (`moondream3-preview/query`): $0.001 / run
- [Moondream3 Preview \[Detect\]](https://doitong.com/developers/models/moondream3-preview/detect.md) (`moondream3-preview/detect`): $0.001 / run
- [Moondream3 Preview \[Point\]](https://doitong.com/developers/models/moondream3-preview/point.md) (`moondream3-preview/point`): $0.001 / run
- [Moondream](https://doitong.com/developers/models/moondream/batched.md) (`moondream/batched`): $0.004 / run
- [Moondream2](https://doitong.com/developers/models/moondream2.md) (`moondream2`): $0.01 / run
- [Moondream2 · Object Detection](https://doitong.com/developers/models/moondream2/object-detection.md) (`moondream2/object-detection`): $0.02 / image
- [Moondream2 · Point Object Detection](https://doitong.com/developers/models/moondream2/point-object-detection.md) (`moondream2/point-object-detection`): $0.02 / image

## Links

- HTML page: https://doitong.com/developers/models/moondream3-preview/caption
- All models and guides for AI agents: https://doitong.com/developers/llms.txt
- OpenAPI 3.1 with this model's typed request body: https://doitong.com/developers/openapi.json?model=moondream3-preview/caption
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/moondream3-preview/caption