The task object

Every field of a task, the result shape for each task type, and what the create, list, status, and result endpoints return.

Every generation and analysis call creates a task, and every task endpoint returns some part of this object. The lifecycle, billing, and file lifetimes are on tasks.

Where each part comes from

Call	Returns
A `POST` that creates a task	`task_id`, `estimated_cost`, sometimes `public_access_token`. See create response
`GET /tasks`	A page of rows: `id`, `type`, `status`, `cost`, timestamps
`GET /tasks/{id}`	The full object
`GET /tasks/{id}/status`	`status` only
`GET /tasks/{id}/result`	`id`, `type`, `status`, `result`
A webhook delivery	The full object, as the event's `data`. See webhook payloads

Poll /status, then read /result. Both are served from a cache and accept a pat_ token. GET /tasks/{id} reads the database and needs an API key.

The object

{
  "data": {
    "id": "tsk_01KE7XWWEQ4MCGWKBQKJ1G47RP",
    "type": "image.generate",
    "status": "completed",
    "request": {
      "model": "black-forest-labs/flux.2-pro",
      "prompt": "A lighthouse at dusk, film grain",
      "count": 1,
      "metadata": { "order_id": "ord_42" }
    },
    "result": {
      "model": "black-forest-labs/flux.2-pro",
      "images": [
        {
          "status": "success",
          "id": "img_V1StGXR8Z5jdHi6BmyT0sC1pQ2rN4wLk",
          "url": "https://cdn.mynth.io/images/img_V1StGXR8Z5jdHi6BmyT0sC1pQ2rN4wLk.webp",
          "mynth_url": "https://cdn.mynth.io/images/img_V1StGXR8Z5jdHi6BmyT0sC1pQ2rN4wLk.webp",
          "size": "1536x1024",
          "format": "webp"
        }
      ]
    },
    "errors": null,
    "cost": "0.03000000",
    "user_id": "user_01JD8G3W1R5T6Y7U8I9O0P1Q2W",
    "api_key_id": "ak_01KE7XWWEQ4MCGWKBQKJ1G47RP",
    "created_at": "2026-07-04T10:00:00.000Z",
    "updated_at": "2026-07-04T10:00:12.000Z"
  }
}

Field	Type	Notes
`id`	string	`tsk_` + a ULID. Sorts by creation time
`type`	string	One of the seven task types. Decides the shape of `request` and `result`
`status`	`pending` \| `completed` \| `failed`	`pending` covers queued and running. A settled task never changes again
`request`	object	The body as accepted, with defaults filled in. See request
`result`	object \| `null`	Set only when `completed`. Shape depends on `type`
`errors`	`[{ code, message? }]` \| `null`	Set only when `failed`
`cost`	decimal string \| `null`	USD charged, 8 decimal places. Set only when `completed`
`user_id`	string	The account that owns the task
`api_key_id`	string \| `null`	The key that created it. `null` for dashboard and playground tasks
`created_at`	ISO 8601 string	UTC
`updated_at`	ISO 8601 string	UTC. The last change

The combinations are fixed:

`status`	`result`	`errors`	`cost`
`pending`	`null`	`null`	`null`
`completed`	set	`null`	set
`failed`	`null`	at least one entry	`null`

completed means the task finished and has a result. It does not mean every item succeeded: a generation can complete with failed images or videos, so check each entry's status in result.images or result.videos. failed means the task as a whole failed: there is no result, nothing is charged, and errors says why. Errors lists the codes.

Money is always a decimal string: cost, estimated_cost, and a video's own cost. Add amounts up with a decimal type, not floats.

Request

request echoes the body after validation:

Defaults are filled in, such as model: "auto" and count: 1 on image.generate, or effort: "high" on image.review.
Field names are snake_case, the same as you send them. A body with a field the endpoint does not define is rejected, so nothing is dropped.
metadata comes back unchanged, here and in every webhook. Put your own ids in it to match a task to your records.
URLs in webhook.custom are cut down to scheme://host, because they often carry a token.

Each endpoint page under Endpoints lists the fields its task type accepts.

Task types

`type`	Created by	`result` holds
`image.generate`	`POST /image/generate`	`model`, `images[]`, `magic_prompt?`
`image.remove_background`	`POST /image/remove-background`	`image`
`image.upscale`	`POST /image/upscale`	`image`
`image.rate`	`POST /image/rate`	`level`
`image.alt`	`POST /image/alt`	`alt`
`image.review`	`POST /image/review`	`score`, `summary`, `findings`, `strengths`
`video.generate`	`POST /video/generate`	`model`, `videos[]`

Fields marked ? are absent, not null, when they do not apply.

`image.generate`

{
  "model": "black-forest-labs/flux.2-pro",
  "images": [
    {
      "status": "success",
      "id": "img_V1StGXR8Z5jdHi6BmyT0sC1pQ2rN4wLk",
      "url": "https://assets.example.com/renders/img_V1StGXR8Z5jdHi6BmyT0sC1pQ2rN4wLk.webp",
      "mynth_url": "https://cdn.mynth.io/images/img_V1StGXR8Z5jdHi6BmyT0sC1pQ2rN4wLk.webp",
      "size": "1536x1024",
      "format": "webp",
      "rating": { "status": "success", "level": "sfw" }
    },
    {
      "status": "failed",
      "error": {
        "code": "restricted_content",
        "message": "The request was blocked by content moderation."
      }
    }
  ],
  "magic_prompt": { "positive": "A lone lighthouse on a rocky shore at dusk, ..." }
}

Field	Type	Notes
`model`	string	The model that ran. With `auto`, the one Mynth picked
`images`	array	One entry per requested image, each `success` or `failed`
`magic_prompt?`	`{ positive, negative? }`	The rewritten prompt, when the request set `magic_prompt: true`

A successful image:

Field	Type	Notes
`status`	`"success"`
`id`	string	`img_` + 32 random characters
`url`	string \| `null`	Your storage when a destination was named, else the same as `mynth_url`. `null` if that upload failed
`mynth_url`	string	Mynth's copy. Always set, served for 7 days
`size`	string	Measured from the file, `{width}x{height}`
`format`	`png` \| `jpg` \| `webp`	What `output.format` asked for, or what the provider returned
`rating?`	object	When the request set `rating`: `{ status: "success", level }` or `{ status: "failed", error: { code } }`

A failed image is { "status": "failed", "error": { "code", "message?" } } with nothing else, and is not charged. Generated images carry no destination block, so a failed upload shows only as url: null.

`image.remove_background`

{
  "image": {
    "id": "img_Q8mZr2LkT0vWc5NhY7pD3xFa9GsJ1bEu",
    "url": "https://cdn.mynth.io/images/img_Q8mZr2LkT0vWc5NhY7pD3xFa9GsJ1bEu.png",
    "mynth_url": "https://cdn.mynth.io/images/img_Q8mZr2LkT0vWc5NhY7pD3xFa9GsJ1bEu.png",
    "size": "1024x1024",
    "format": "png"
  }
}

image has the fields of a successful image.generate entry, without status and rating. format is png or webp. There is no per-item failure: if the work fails, the task is failed.

When the request named a destination, image also carries destination: { status: "success", name }, or { status: "failed", name, error: { code, message?, provider_response? } } next to url: null.

`image.upscale`

{
  "image": {
    "id": "img_Hn4cW8pLx2RsT6vYb0QjM9kE3dAf7ZuG",
    "url": "https://cdn.mynth.io/images/img_Hn4cW8pLx2RsT6vYb0QjM9kE3dAf7ZuG.png",
    "mynth_url": "https://cdn.mynth.io/images/img_Hn4cW8pLx2RsT6vYb0QjM9kE3dAf7ZuG.png",
    "size": "3072x4608",
    "format": "png"
  }
}

Same shape as image.remove_background, with destination under the same rules. format is png, jpg, or webp. size is what the provider returned, which can differ slightly from the source times the factor.

`image.rate`

{ "level": "sfw" }

level is sfw or nsfw by default, or one of your value strings with custom levels.

`image.alt`

{ "alt": "A white lighthouse on dark rocks, lit by an orange sunset sky" }

alt is 1 to 160 characters.

`image.review`

{
  "score": 3,
  "summary": "Clean composition with one visible defect in the left hand.",
  "findings": [
    {
      "finding": "The left hand has six fingers",
      "category": "anatomy",
      "severity": "major",
      "where": "Bottom left, the hand resting on the railing",
      "confidence": "high"
    }
  ],
  "strengths": [{ "strength": "Warm, consistent lighting", "confidence": "medium" }]
}

Field	Type	Notes
`score`	number, 1 to 4	Median of the reviewers' scores. Higher is better
`summary`	string	A short prose summary
`findings[].category`	string	Usually `anatomy`, `text`, `composition`, `artifact`, `color`, or `lighting`. An open set
`findings[].severity`	`critical` \| `major` \| `minor`
`findings[].confidence`	`low` \| `medium` \| `high`	Reviewer agreement: bare threshold, majority, strong consensus
`strengths[]`	`{ strength, confidence }`	Same `confidence` scale

`video.generate`

{
  "model": "bytedance/seedance-2.0-mini",
  "videos": [
    {
      "status": "success",
      "id": "vid_3HkP9wQz7LmR2tXc8VbN5dFy0JsA4gUe",
      "url": "https://cdn.mynth.io/videos/vid_3HkP9wQz7LmR2tXc8VbN5dFy0JsA4gUe.mp4",
      "mynth_url": "https://cdn.mynth.io/videos/vid_3HkP9wQz7LmR2tXc8VbN5dFy0JsA4gUe.mp4",
      "cost": "0.40500000",
      "duration": 5,
      "resolution": "720p",
      "aspect_ratio": "9:16",
      "audio": true
    }
  ]
}

Field	Type	Notes
`id`	string	`vid_` + 32 random characters
`url`	string \| `null`	The same as `mynth_url` today. Nullable, as on images, so video destinations can be added without a breaking change. Write `url ?? mynth_url`
`mynth_url`	string	Mynth's copy. Always set
`cost`	decimal string	What this video cost
`duration`	number	Seconds
`resolution`	`480p` \| `720p` \| `1080p` \| `4k`
`aspect_ratio`	string \| `null`	The ratio it was rendered at, such as `9:16`. `null` when a first frame set the shape
`audio`	boolean	Whether the video has generated audio

A failed video is { "status": "failed", "error": { "code", "message?" } }, like a failed image.

Create response

Every POST that creates a task answers 201:

{
  "data": {
    "task_id": "tsk_01KE7XWWEQ4MCGWKBQKJ1G47RP",
    "estimated_cost": "0.03",
    "public_access_token": "pat_eyJhbGciOiJIUzI1NiJ9..."
  }
}

Field	Notes
`task_id`	Pass it to every task endpoint
`estimated_cost`	USD held on your balance until the task settles. The final `cost` is normally equal or lower
`public_access_token?`	Only when the request set `generate_public_access_token: true`, on image generate, remove background, upscale, and video generate. Rules

The media is never in this response. Wait for the task with polling or a webhook.

Listing tasks

GET /tasks returns the calling key's tasks, newest first. Rows omit request and result, so fetch a task by id for those.

Query	Default	Notes
`limit`	`20`	1 to 100
`after`	none	A task id. Returns tasks older than it

{
  "data": [
    {
      "id": "tsk_01KE7XWWEQ4MCGWKBQKJ1G47RP",
      "type": "image.generate",
      "status": "completed",
      "cost": "0.03000000",
      "created_at": "2026-07-04T10:00:00.000Z",
      "updated_at": "2026-07-04T10:00:12.000Z"
    }
  ]
}

There is no has_more and no total. To page, pass the last id you received as after. A page shorter than limit is the last one.

let after: string | undefined;

do {
  const url = new URL("https://api.mynth.io/tasks");
  url.searchParams.set("limit", "100");
  if (after) url.searchParams.set("after", after);

  const res = await fetch(url, {
    headers: { Authorization: `Bearer ${process.env.MYNTH_API_KEY}` },
  });
  const { data } = await res.json();

  for (const task of data) console.log(task.id, task.status, task.cost);

  after = data.length === 100 ? data.at(-1).id : undefined;
} while (after);

After a create request times out, look here before resending. If the task is listed, it was created, and sending the request again would create and charge a second one.

Status and result

{ "data": { "status": "pending" } }

{
  "data": {
    "id": "tsk_01KE7XWWEQ4MCGWKBQKJ1G47RP",
    "type": "image.alt",
    "status": "completed",
    "result": { "alt": "A white lighthouse on dark rocks, lit by an orange sunset sky" }
  }
}

/result answers 200 while the task is pending, with result: null. It never includes errors, so for a failed task read GET /tasks/{id}.

Next steps

Tasks: statuses, billing, retries, and file lifetimes.
Webhook payloads: the same result, pushed to you.
Errors: the codes in errors and on failed items.