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Z-Image Plus API

by Alibaba

Z-Image at exact custom sizes up to 1536 px

alibaba/z-image-plus/text-to-image
  • Create Image

Call it with the model name alibaba/z-image-plus/text-to-image on POST /jobs/createTask, from $0.01235.

Model namealibaba/z-image-plus/text-to-image
EndpointPOST https://api.popnow.ai/api/v1/jobs/createTask
# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $IDEMPOTENCY_KEY" \
  -d '{
  "model": "alibaba/z-image-plus/text-to-image",
  "input": {
    "prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette"
  }
}'

# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

The input is built from the schema below, so it passes validation as written. Change the prompt and links to your own.

Price

OptionUSD per image
false$0.01235
true$0.0133

Billed in USD · Every option and its price: GET /models/alibaba/z-image-plus/text-to-image

Parameters

These fields come from the same schema we check every request against. Fields that are not listed are rejected.

  • promptstringRequired

    Describe the image to generate.

    Range
    1 – … chars
  • widthintegerOptional

    Output image width in pixels.

    Default
    1024
    Range
    256 – 1536
  • heightintegerOptional

    Output image height in pixels.

    Default
    1536
    Range
    256 – 1536
  • enable_prompt_expansionbooleanOptionalChanges the price

    Lets the model add detail to a short prompt.

    Default
    false
  • seedintegerOptional

    Reuse the same number to get a repeatable result.

    Range
    0 – 2147483647
Raw JSON Schema
{
  "type": "object",
  "required": [
    "prompt"
  ],
  "properties": {
    "seed": {
      "type": "integer",
      "maximum": 2147483647,
      "minimum": 0,
      "description": "Random seed; zero requests a random seed."
    },
    "width": {
      "type": "integer",
      "default": 1024,
      "maximum": 1536,
      "minimum": 256,
      "description": "Output image width in pixels."
    },
    "height": {
      "type": "integer",
      "default": 1536,
      "maximum": 1536,
      "minimum": 256,
      "description": "Output image height in pixels."
    },
    "prompt": {
      "type": "string",
      "minLength": 1,
      "description": "Describe the image to generate."
    },
    "enable_prompt_expansion": {
      "type": "boolean",
      "default": false,
      "description": "Expand the prompt before generation."
    }
  },
  "additionalProperties": false
}

Responses, polling and callbacks

Every model works the same way: create a task, then poll it or wait for a callback.

Price it first

cURL
curl -X POST https://api.popnow.ai/api/v1/jobs/quote \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "alibaba/z-image-plus/text-to-image",
  "input": {
    "prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette"
  }
}'

Send the same request body to POST /jobs/quote to see the estimated and maximum USD charge before running. A quote does not run the task or charge your balance.

Accepted

HTTP
HTTP/1.1 202 Accepted

{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "state": "queued"
  },
  "request_id": "req_example_create"
}

HTTP 202 means accepted: the maximum USD amount is held until settlement. When a task is accepted, we reserve the maximum quoted amount from your API balance. On completion, we charge for actual usage, never more than the hold, and release the remainder. If the task fails, the hold is released.

Check status

cURL
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

Poll every few seconds with backoff and stop once state is succeeded, failed, canceled or expired.

Finished task

JSON
{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "model": "alibaba/z-image-plus/text-to-image",
    "state": "succeeded",
    "output": {
      "assets": [
        {
          "url": "https://cdn.popnow.ai/tasks/task_01k3m8x9q2z4v7n5p6r8s0t1w3/output.png?signature=FROM_RESPONSE",
          "expiresAt": "2026-10-17T12:20:00Z",
          "mime": "image/png",
          "width": 1024,
          "height": 1024
        }
      ]
    },
    "settled": true
  },
  "request_id": "req_example_record"
}

Download from url before expiresAt. Need a fresh link later? Ask POST /common/download-url.

Verify a callback

Node.js
import { createHash, createHmac, timingSafeEqual } from "node:crypto";
import express from "express";

const app = express();
// express.raw keeps the exact bytes that were signed; express.json would not match.
app.post("/hooks/popnow", express.raw({ type: "application/json" }), (req, res) => {
  const timestamp = req.header("X-Webhook-Timestamp");
  const signature = req.header("X-Webhook-Signature") ?? "";
  const body = JSON.parse(req.body.toString("utf8"));
  const taskId = body.data?.taskId ?? body.task_id;
  const digest = createHash("sha256").update(req.body).digest("hex");
  const expected = createHmac("sha256", process.env.POPNOW_WEBHOOK_SECRET)
    .update(`${taskId}.${timestamp}.${digest}`)
    .digest("base64");
  const ok = expected.length === signature.length && timingSafeEqual(Buffer.from(expected), Buffer.from(signature));
  // Check the signature first, then reject anything older than five minutes.
  if (!ok || Math.abs(Date.now() / 1000 - Number(timestamp)) > 300) return res.status(401).end();
  res.status(200).end(); // answer fast, then fetch the task and store its files
});

With callBackUrl set, we post the finished task to you. Check the signature against the raw body before you trust it.

Send a local file

cURL
curl -X POST https://api.popnow.ai/api/v1/common/upload-url \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"contentType": "image/png", "bytes": 482113}'

# PUT the file bytes to data.uploadUrl with every header in data.headers, then commit it:
curl -X POST https://api.popnow.ai/api/v1/files/$FILE_ID/commit \
  -H "Authorization: Bearer $POPNOW_API_KEY"
# The commit returns a popnow://f/... reference. Put it in any image, video or
# audio field of the task input instead of a public https URL.

Public https links work as they are. Local files go through upload-url and commit first.

About Z-Image Plus

Z-Image at exact custom sizes up to 1536 px.

Call it with the model name alibaba/z-image-plus/text-to-image on POST /jobs/createTask, from $0.01235.

Request parameters

ParameterRequiredDescription
seedNoReuse the same number to get a repeatable result. ≥ 0 · ≤ 2147483647
widthNoOutput image width in pixels. ≥ 256 · ≤ 1536 · Default: 1024
heightNoOutput image height in pixels. ≥ 256 · ≤ 1536 · Default: 1536
promptYesDescribe the image to generate.
enable_prompt_expansionNoLets the model add detail to a short prompt. Default: false

Pricing

Prices are in USD. The API uses a separate USD balance. Website credits cannot be used or transferred to it, and API funds cannot be transferred to website credits. When a task is accepted, we reserve the maximum quoted amount from your API balance. On completion, we charge for actual usage, never more than the hold, and release the remainder. If the task fails, the hold is released.

OptionUSD per image
false$0.01235
true$0.0133

Send the same request body to POST /jobs/quote to see the estimated and maximum USD charge before running. A quote does not run the task or charge your balance.

API quick start

Call the Z-Image Plus API in three steps

  1. Create an API key. Sign in to PopNow and create a key in the API console. Keys start with sk-popnow-. API calls use your separate USD balance.
  2. Send the request. POST /jobs/createTask with model alibaba/z-image-plus/text-to-image and an input object that follows the parameter table. The response returns a task ID straight away.
  3. Get the result. Poll GET /jobs/recordInfo with the task ID, or pass a callBackUrl and we post the result to it. Download the output links when the task succeeds.
# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $IDEMPOTENCY_KEY" \
  -d '{
  "model": "alibaba/z-image-plus/text-to-image",
  "input": {
    "prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette"
  }
}'

# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

Replace the prompt and any links with your own. The API tab has the response, polling and callback reference.

Z-Image Plus API questions

How much does the Z-Image Plus API cost?

Z-Image Plus costs $0.01235 per image. Prices by option: false $0.01235 per image, true $0.0133 per image. The API uses a separate USD balance. Website credits cannot be used or transferred to it, and API funds cannot be transferred to website credits. When a task is accepted, we reserve the maximum quoted amount from your API balance. On completion, we charge for actual usage, never more than the hold, and release the remainder. If the task fails, the hold is released.

What is the model name for Z-Image Plus in the API?

Put alibaba/z-image-plus/text-to-image for Create Image in the model field of POST /jobs/createTask.

More about Z-Image Plus