MOSS Image API: Pricing, Documentation

Authentication

All requests require an API key passed via header.

Webhook (Optional)

Instead of polling, you can receive a Webhook callback when the request reaches a terminal state. Provide a Webhook URL via header on the submit request.

Example: enable Webhook

curl -X POST 'https://gateway.pixazo.ai/moss-image/v1/text-to-image' \
  -H 'Content-Type: application/json' \
  -H 'Ocp-Apim-Subscription-Key: YOUR_SUBSCRIPTION_KEY' \
  -H 'X-Webhook-URL: https://your-server.com/webhook' \
  --data-raw '{"prompt": "A bakery storefront at dawn with a hand-painted sign that reads FRESH BREAD DAILY", "image_size": "square_hd"}'

Callback Payload (success)

{
  "request_id": "moss-image_019dxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
  "status": "COMPLETED",
  "model_id": "moss-image",
  "error": null,
  "output": {
    "media_url": [
      "https://pub-582b7213209642b9b995c96c95a30381.r2.dev/v1/{request_id}/output.jpg"
    ],
    "media_type": "image/jpeg"
  },
  "created_at": "2026-10-09T10:04:54.387Z",
  "completed_at": "2026-10-09 10:06:21"
}

Failure callback shape

{
  "request_id": "moss-image_019dxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
  "status": "ERROR",
  "model_id": "moss-image",
  "error": "Description of the failure"
}

Delivery semantics

• terminal mode: one Webhook callback when the request is COMPLETED or ERROR.
• sync mode: a Webhook callback on every poll while the request is processing (status PROCESSING), plus the final COMPLETED/ERROR callback.
• Callbacks are idempotent on request_id — de-duplicate on it.
• Respond 200 within a few seconds; the Webhook endpoint must be HTTPS.

Request Parameters

Good to know

• Each request returns one image. batch_size, num_images, number_of_images, n and count are rejected — send one request per image.
• This API makes still images and has no length setting. duration, seconds, num_frames, frames_per_second and music_length_ms are rejected.
• Send every field at the top level of the JSON body; parameters, input, content and text are rejected.
• image_urls, image_url and image are rejected: this API makes images from a text prompt only.
• Leave image_size out for square_hd, or choose another of the six preset names. Custom widths and heights are not available on this API.
• enable_safety_checker is always on: send true or leave it out.
• Use the JSON types shown: prompt, negative_prompt, image_size and output_format are strings, num_inference_steps and seed are whole numbers, guidance_scale is a number, and enable_prompt_expansion and enable_safety_checker are true or false.
• Omit a field instead of sending null.
• Results are always returned as a URL in output.media_url; sync_mode is accepted only as false.
• Webhooks are set with the X-Webhook-URL / X-Webhook-Mode headers; webhook_url, webhook_mode and callback_url in the JSON body are rejected.
• stream is not supported: the result is delivered when the job completes.

Output Size and Text

• Choose one of six preset names in image_size; leave it out for square_hd. Custom widths and heights are not available on this API.
• The size sets the amount billed: see How Billing Is Measured below.
• To write words in the image, put them in the prompt, for example a sign that reads OPEN LATE.

Example: a portrait poster with a negative prompt

{
  "prompt": "A travel poster for a mountain lake at sunrise with the title LAKE DAYS in large letters",
  "negative_prompt": "blurry, low quality",
  "image_size": "portrait_4_3",
  "output_format": "png"
}

Example: repeat an image with a seed

{
  "prompt": "A neon sign that reads OPEN LATE above a small noodle shop at night",
  "image_size": "landscape_4_3",
  "seed": 42
}

Request Headers

Response Handling

Parameter problems are caught when you submit and returned as a 400, before any hold is placed on your balance. Problems that need the model to run are reported through the status endpoint as status: "ERROR", with a message in error saying what went wrong. Failed requests are not billed — the hold is released in full.

Example error responses

A refused request returns error, a message that joins every problem found, and the same problems one by one in violations.

Missing prompt (synchronous 400)

{
  "error": "Invalid request parameters",
  "message": "'prompt' is required",
  "violations": [
    "'prompt' is required"
  ]
}

A size this API does not offer (synchronous 400)

{
  "error": "Invalid request parameters",
  "message": "'image_size' must be string (got object); 'image_size' must be one of: square_hd (the default), square, portrait_4_3, portrait_16_9, landscape_4_3 or landscape_16_9. Custom sizes are not available on this API.",
  "violations": [
    "'image_size' must be string (got object)",
    "'image_size' must be one of: square_hd (the default), square, portrait_4_3, portrait_16_9, landscape_4_3 or landscape_16_9. Custom sizes are not available on this API."
  ]
}

An image sent to text to image (synchronous 400)

{
  "error": "Invalid request parameters",
  "message": "'image_urls' must be one of:  (got [\"https://pub-582b7213209642b9b995c96c95a30381.r2.dev/doc-assets/images/input.jpg\"]); 'image_urls' is not accepted: this API makes images from a text prompt only.",
  "violations": [
    "'image_urls' must be one of:  (got [\"https://pub-582b7213209642b9b995c96c95a30381.r2.dev/doc-assets/images/input.jpg\"])",
    "'image_urls' is not accepted: this API makes images from a text prompt only."
  ]
}

More than one image per request (synchronous 400)

{
  "error": "Invalid request parameters",
  "message": "'num_images' must be one of:  (got 2); 'num_images' is not supported: each request returns one image. Send one request per image.",
  "violations": [
    "'num_images' must be one of:  (got 2)",
    "'num_images' is not supported: each request returns one image. Send one request per image."
  ]
}

An output format this API does not offer (synchronous 400)

{
  "error": "Invalid request parameters",
  "message": "'output_format' must be one of: \"jpeg\", \"png\", \"webp\" (got \"gif\")",
  "violations": [
    "'output_format' must be one of: \"jpeg\", \"png\", \"webp\" (got \"gif\")"
  ]
}

Retrieving Results

Poll the status endpoint with the request_id from the submit response until status is COMPLETED or ERROR, then download the image from output.media_url. Treat any status other than QUEUED, PROCESSING or COMPLETED as a failure.

Endpoint

GET https://gateway.pixazo.ai/v2/requests/status/{request_id}
Ocp-Apim-Subscription-Key: YOUR_SUBSCRIPTION_KEY

cURL example

curl 'https://gateway.pixazo.ai/v2/requests/status/moss-image_019dxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx' \
  -H 'Ocp-Apim-Subscription-Key: YOUR_SUBSCRIPTION_KEY'

Completed response

{
  "request_id": "moss-image_019dxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
  "status": "COMPLETED",
  "model_id": "moss-image",
  "error": null,
  "output": {
    "media_url": [
      "https://pub-582b7213209642b9b995c96c95a30381.r2.dev/v1/{request_id}/output.jpg"
    ],
    "media_type": "image/jpeg"
  },
  "created_at": "2026-10-09T10:04:54.387Z",
  "completed_at": "2026-10-09 10:06:21"
}

Response Fields

Status Values & Flow

QUEUED → PROCESSING → COMPLETED (success) or ERROR (failure).

Typical workflow

1. Send the request to POST https://gateway.pixazo.ai/moss-image/v1/text-to-image.
2. Save the request_id from the 202 response.
3. Poll GET /v2/requests/status/{request_id} every 10 seconds or so, or use a Webhook instead.
4. When status is COMPLETED, download the image from output.media_url.

How Billing Is Measured

Billing is measured per megapixel of the output image (1 megapixel = 1,048,576 pixels). Each preset counts as its standard size: square_hd 1 megapixel, square 0.25, portrait_4_3 and landscape_4_3 0.75, portrait_16_9 and landscape_16_9 0.5625. Without image_size, square_hd applies. The prompt and the other settings do not change the amount. The amount is placed as a hold when the request is submitted and released in full if the request fails. The current rate is shown in the pricing panel on this page.