Image Upscaler API: 2K, 4K & 8K Enhancement

Overview

Image Upscaler is an asynchronous image-to-image API for enlarging and enhancing one source image. Use it when you already have an image URL and want a higher-resolution output without writing a text prompt.

Capability	Value
Model ID	`image-upscaler`
Mode	`image-to-image` only
Input images	Exactly 1 public image URL
Prompt	Not supported
Resolution tiers	`2k`, `4k`, `8k`
Output formats	`jpg`, `png`, `webp`

Endpoint and authentication

Base URL:

https://api.apixo.ai/api/v1

Method	Endpoint	Purpose
`POST`	`/generateTask/image-upscaler`	Submit an upscaling task
`GET`	`/statusTask/image-upscaler?taskId={taskId}`	Poll task status and retrieve results

All requests require your APIXO API key:

Authorization: Bearer YOUR_API_KEY

Submit requests also require:

Content-Type: application/json

Copy-paste async quickstart

This minimal request submits a 4k JPG upscaling task and returns a taskId.

curl -X POST "https://api.apixo.ai/api/v1/generateTask/image-upscaler" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "request_type": "async",
    "input": {
      "mode": "image-to-image",
      "image_urls": [
        "https://example.com/input.jpg"
      ],
      "resolution": "4k",
      "output_format": "jpg"
    }
  }'

Successful response:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678"
  }
}

Save the taskId; you need it to poll for the final result.

Poll for result

curl -X GET "https://api.apixo.ai/api/v1/statusTask/image-upscaler?taskId=task_12345678" \
  -H "Authorization: Bearer YOUR_API_KEY"

Processing response:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "processing",
    "createTime": 1767965610929
  }
}

Success response:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "success",
    "resultJson": "{\"resultUrls\":[\"https://file.apixo.ai/upscaled-image.jpg\"]}",
    "createTime": 1767965610929,
    "completeTime": 1767965652317,
    "costTime": 41388
  }
}

Failed response:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "failed",
    "failCode": "Unknown error",
    "failMsg": "Unknown error.",
    "createTime": 1767965610929,
    "completeTime": 1767965620132
  }
}

Parse resultJson after state becomes success:

const payload = JSON.parse(data.resultJson);
const imageUrls = payload.resultUrls;

Parse resultJson only after state becomes success.

Request body

Default 4k JPG

{
  "request_type": "async",
  "input": {
    "mode": "image-to-image",
    "image_urls": [
      "https://example.com/input.jpg"
    ],
    "resolution": "4k",
    "output_format": "jpg"
  }
}

8k WebP

{
  "request_type": "async",
  "input": {
    "mode": "image-to-image",
    "image_urls": [
      "https://example.com/product-shot.png"
    ],
    "resolution": "8k",
    "output_format": "webp"
  }
}

Parameters

string

default:"async"

required

Result delivery mode. Use async for polling with statusTask, or callback for webhook delivery.

string

Required when request_type is callback. Must be a public HTTPS URL that can receive the final task payload. See Webhooks.

object

required

Image Upscaler input parameters.

Show properties

string

default:"image-to-image"

Upscaling mode. The only supported value is image-to-image. If omitted, the backend defaults to image-to-image.

string[]

required

Source image URLs. Must contain exactly 1 non-empty public image URL in JPG, JPEG, PNG, or WEBP format.

string

default:"4k"

Target resolution tier. Supported values: 2k, 4k, 8k. Values are case-insensitive and normalized to lowercase.

string

default:"jpg"

Output image format. Supported values: jpg, png, webp. jpeg is accepted as an input alias for jpg.

Response format

Submit task response

POST /generateTask/image-upscaler returns a task ID when the task is accepted:

integer

API status code. 200 means the task was accepted.

string

Human-readable status message.

string

Unique task identifier used with the status endpoint.

Status response fields

string

Unique task identifier.

string

Current task state: pending, processing, success, or failed.

string

JSON string containing the upscaled image URL in resultUrls. Present when state is success.

string

Machine-readable failure code. Present when state is failed.

string

Human-readable failure message. Present when state is failed.

integer

Task creation timestamp in Unix milliseconds.

integer

Task completion timestamp in Unix milliseconds. Present after completion.

integer

Processing duration in milliseconds. Present in successful polling responses when timing data is available.

Webhook callback mode

Use callback mode when your backend should receive the final result automatically instead of polling.

curl -X POST "https://api.apixo.ai/api/v1/generateTask/image-upscaler" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "request_type": "callback",
    "callback_url": "https://your-server.com/webhooks/apixo",
    "input": {
      "mode": "image-to-image",
      "image_urls": [
        "https://example.com/input.jpg"
      ],
      "resolution": "4k",
      "output_format": "jpg"
    }
  }'

Successful callback payload:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "success",
    "resultJson": "{\"resultUrls\":[\"https://file.apixo.ai/upscaled-image.jpg\"]}",
    "createTime": 1767965610929,
    "completeTime": 1767965652317,
    "costTime": 41388
  }
}

See Webhooks for delivery requirements and retry behavior.

Billing

New non-LLM requests use 1 credit = $0.001. Calculate the full amount, including billable quantity and add-ons, apply the applicable account discount, then round the request total upward to the next whole credit. Agreed fixed unit prices retain their precision and replace the standard price and discount; final rounding still applies. See credit conversion and rounding. Image Upscaler is billed per submitted image at $0.01 / image. The price does not vary by resolution or output_format.

Billing dimension	Value
Unit	`PER_IMAGE`
APIXO price	`$0.01 / image`
Parameter-based tiers	None
Affected by `resolution`	No
Affected by `output_format`	No

For current API rates in USD, see API pricing.

Latency and polling

Image Upscaler tasks run asynchronously. Actual latency varies by source image size, selected target resolution, queue load, and result storage time.

Phase	Status you may see	Client behavior
Generation in progress	`processing`	Keep polling
Completed	`success`	Parse `resultJson`
Failed	`failed`	Read `failCode` and `failMsg`

Recommended polling pattern:

Use case	Recommended first poll	Poll interval
Normal workloads	10s-15s after task creation	5s-10s
8k or high-concurrency workloads	Prefer callback mode	If polling, use 10s or longer

For production queues or large batches, use callback mode to avoid frequent polling and to handle longer 8k jobs more cleanly.

Rate limits and concurrency can vary by account, API key, and route. If you receive 429, slow down requests and retry with backoff. For account-level details, see System APIs.

Errors and troubleshooting

HTTP errors

Code	Meaning	What to do
`400`	Invalid request body, mode, image URL shape, resolution, or output format	Fix the request before retrying
`401`	Missing or invalid API key	Check the `Authorization` header
`402`	Insufficient balance or quota	Add balance or switch account/key
`403`	Key or route cannot access the model	Check permissions and route strategy
`404`	Task not found	Verify the `taskId` and model ID
`429`	Rate limit or concurrency limit reached	Retry with exponential backoff
`500`	Server error or unknown task failure	Retry with backoff
`502`	Service error	Retry with backoff
`504`	Service timeout	Retry or use callback mode for long-running jobs

Request validation

Condition	Backend behavior
Missing `input`	Returns `The required parameter {{input}} is missing.`
Invalid `mode`	Returns `Invalid mode type. Supported: image-to-image`
Missing `image_urls`	Returns `The required parameter {{image_urls}} is missing.`
`image_urls` is not an array	Returns `The parameter {{image_urls}} must be Array type.`
`image_urls` length is not 1	Returns `The parameter {{image_urls}} must contain exactly 1 image.`
`image_urls[0]` is not a string	Returns `The parameter {{image_urls}} Array elements must be String type.`
`image_urls[0]` is empty	Returns `The parameter {{image_urls}} cannot contain empty string.`
Invalid `resolution`	Returns `The parameter {{resolution}} must be either '2k', '4k' or '8k'.`
Invalid `output_format`	Returns `The parameter {{output_format}} must be either 'jpg', 'png' or 'webp'.`

Task failure codes

Fail code	Meaning	What to do
`ImageFormatIncorrect`	The service rejected the input image format	Use a direct public JPG, PNG, or WebP image URL
`SensitiveContent`	Input or generated content was rejected by safety checks	Use a different image
`RateLimited`	A rate limit was reached	Retry with backoff
`Timeout`	The task timed out	Retry or use callback mode
`Unknown error`	An unknown task failure occurred	Retry with backoff or contact support with the `taskId`

See Error Codes for the full error reference.

MCP integration

The complete model schema declares result decoding in mcp.result and supported file bindings in mcp.attachments. These are client integration metadata, not generation input parameters. Attachment paths: image_urls. Preserve the user’s file order. Model parameter validation remains on the API.

​Overview

​Endpoint and authentication

​Copy-paste async quickstart

​Poll for result

​Request body

​Default 4k JPG

​8k WebP

​Parameters

​Response format

​Submit task response

​Status response fields

​Webhook callback mode

​Billing

​Latency and polling

​Errors and troubleshooting

​HTTP errors

​Request validation

​Task failure codes

​MCP integration

​Related links

Overview

Endpoint and authentication

Copy-paste async quickstart

Poll for result

Request body

Default 4k JPG

8k WebP

Parameters

Response format

Submit task response

Status response fields

Webhook callback mode

Billing

Latency and polling

Errors and troubleshooting

HTTP errors

Request validation

Task failure codes

MCP integration

Related links