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FLUX 3 Klein API

Black Forest Labs 出品

快速出图的 FLUX 3 Klein,多参考图改图,支持 1K 或 2K

black-forest-labs/flux-3-klein/edit
  • 最高 2K
  • 最多 10 张参考图
  • 16 种画幅
  • 生成图片
  • 编辑图片

在 POST /jobs/createTask 里把模型名写成 black-forest-labs/flux-3-klein/edit 即可调用,US$0.0192 起。

调用名black-forest-labs/flux-3-klein/edit
接口POST 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": "black-forest-labs/flux-3-klein/edit",
  "input": {
    "prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette",
    "image_urls": [
      "https://media.popnow.ai/influencer/examples/marco.webp"
    ],
    "aspect_ratio": "auto",
    "resolution": "1k",
    "output_format": "jpeg"
  }
}'

# 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"

input 按下面的 Schema 生成,原样就能通过校验。把提示词和链接换成你自己的即可。

价格

选项USD /张
resolution 1KUS$0.0192
resolution 2KUS$0.0768

美元计费 · 全部选项及价格:GET /models/black-forest-labs/flux-3-klein/edit

限制

分辨率
1K · 2K
画面比例
auto · 1:1 · 16:9 · 9:16 · 4:3 · 3:4 +11
参考图
10
提示词长度(字符)
5,000
单个上传上限
10 MB

参数

这些字段来自我们校验每个请求所用的同一份 Schema。没列出的字段会被拒绝。

  • promptstring必填

    Say what to change and what must stay the same; name each source as <ref_image_1>, <ref_image_2>.

    范围
    1 – 5000 chars
  • image_urlsarray<string>必填影响价格

    要编辑或合成的照片。在提示词里说明每张的作用。

    范围
    1 – 10 items · image/jpeg, image/png, image/webp, image/gif · ≤ 10 MB
  • aspect_ratiostring可选

    画面形状:横版、方形或竖版。

    默认值
    "auto"
    可选值
    "auto""1:1""16:9""9:16""4:3""3:4""3:2""2:3""4:5""5:4""21:9""9:21""2:1""1:2""3:1""1:3""custom"
  • resolutionstring可选影响价格

    输出尺寸。越大越清晰,价格也越高。

    默认值
    "1k"
    可选值
    "1k""2k"
  • widthinteger可选

    Output width in pixels when aspect_ratio is custom, 256 to 1024 (1024 if left out); height works the same way. The price still follows resolution.

    范围
    256 – 1024
  • heightinteger可选

    Output height in pixels when aspect_ratio is custom, 256 to 1024 (1024 if left out); width works the same way. The price still follows resolution.

    范围
    256 – 1024
  • enable_prompt_expansionboolean可选

    让模型给短提示词补充细节。

    默认值
    false
  • output_formatstring可选

    结果的文件格式。

    默认值
    "jpeg"
    可选值
    "jpeg""png""webp"
  • seedinteger可选

    用同一个数字,结果就能复现。

    范围
    0 – 2147483647
原始 JSON Schema
{
  "additionalProperties": false,
  "properties": {
    "aspect_ratio": {
      "default": "auto",
      "description": "Output aspect ratio; auto keeps the shape of the first source image, custom lets you set width and height.",
      "enum": [
        "auto",
        "1:1",
        "16:9",
        "9:16",
        "4:3",
        "3:4",
        "3:2",
        "2:3",
        "4:5",
        "5:4",
        "21:9",
        "9:21",
        "2:1",
        "1:2",
        "3:1",
        "1:3",
        "custom"
      ],
      "type": "string"
    },
    "enable_prompt_expansion": {
      "default": false,
      "description": "Rewrite the prompt into a fuller description before generating. Off by default, so the prompt is followed word for word.",
      "type": "boolean"
    },
    "height": {
      "description": "Output height in pixels when aspect_ratio is custom, 256 to 1024 (1024 if left out); width works the same way. The price still follows resolution.",
      "maximum": 1024,
      "minimum": 256,
      "type": "integer"
    },
    "image_urls": {
      "description": "One to ten source images, in the order your prompt refers to them. The second and third each raise the price a little; more do not.",
      "items": {
        "contentMediaType": [
          "image/jpeg",
          "image/png",
          "image/webp",
          "image/gif"
        ],
        "format": "uri",
        "minLength": 1,
        "type": "string"
      },
      "maxItems": 10,
      "minItems": 1,
      "type": "array"
    },
    "output_format": {
      "default": "jpeg",
      "description": "File format of the returned image.",
      "enum": [
        "jpeg",
        "png",
        "webp"
      ],
      "type": "string"
    },
    "prompt": {
      "description": "Say what to change and what must stay the same; name each source as <ref_image_1>, <ref_image_2>.",
      "maxLength": 5000,
      "minLength": 1,
      "type": "string"
    },
    "resolution": {
      "default": "1k",
      "description": "Output size tier: 1k is about one megapixel, 2k about four.",
      "enum": [
        "1k",
        "2k"
      ],
      "type": "string"
    },
    "seed": {
      "description": "Random seed for controlled comparisons.",
      "maximum": 2147483647,
      "minimum": 0,
      "type": "integer"
    },
    "width": {
      "description": "Output width in pixels when aspect_ratio is custom, 256 to 1024 (1024 if left out); height works the same way. The price still follows resolution.",
      "maximum": 1024,
      "minimum": 256,
      "type": "integer"
    }
  },
  "required": [
    "prompt",
    "image_urls"
  ],
  "type": "object"
}

响应、轮询与回调

所有模型的用法都一样:先建任务,再轮询,或者等回调。

先报价

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": "black-forest-labs/flux-3-klein/edit",
  "input": {
    "prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette",
    "image_urls": [
      "https://media.popnow.ai/influencer/examples/marco.webp"
    ],
    "aspect_ratio": "auto",
    "resolution": "1k",
    "output_format": "jpeg"
  }
}'

运行前,将相同请求体发送到 POST /jobs/quote,可查看预计费用和最高费用,单位为美元。报价不会运行任务或扣款。

已受理

HTTP
HTTP/1.1 202 Accepted

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

HTTP 202 表示已受理:最高美元金额已冻结,等待结算。 任务受理时,从 API 余额中冻结报价的最高金额;完成后按实际用量结算,实扣不超过冻结额,并释放剩余金额。任务失败则释放冻结额。

查询状态

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

每隔几秒查一次并逐步拉长间隔,state 变成 succeeded、failed、canceled 或 expired 时停止。

完成的任务

JSON
{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "model": "black-forest-labs/flux-3-klein/edit",
    "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"
}

在 expiresAt 之前从 url 下载。之后要新链接,请调用 POST /common/download-url。

校验回调

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
});

设置了 callBackUrl,我们会把完成的任务发给你。先用原始请求体校验签名,再信任它。

上传本地文件

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.

公开的 https 链接可以直接用。本地文件要先经过 upload-url 和 commit。

关于 FLUX 3 Klein

快速出图的 FLUX 3 Klein,多参考图改图,支持 1K 或 2K。

在 POST /jobs/createTask 里把模型名写成 black-forest-labs/flux-3-klein/edit 即可调用,US$0.0192 起。

请求参数

参数必填说明
aspect_ratio否画面形状:横版、方形或竖版。 auto · 1:1 · 16:9 · 9:16 · 4:3 · 3:4 · 3:2 · 2:3 · 4:5 · 5:4 · 21:9 · 9:21 · 2:1 · 1:2 · 3:1 · 1:3 · custom · 默认值: auto
enable_prompt_expansion否让模型给短提示词补充细节。 默认值: false
height否Output height in pixels when aspect_ratio is custom, 256 to 1024 (1024 if left out); width works the same way. The price still follows resolution. ≥ 256 · ≤ 1024
image_urls是要编辑或合成的照片。在提示词里说明每张的作用。
output_format否结果的文件格式。 jpeg · png · webp · 默认值: jpeg
prompt是Say what to change and what must stay the same; name each source as <ref_image_1>, <ref_image_2>.
resolution否输出尺寸。越大越清晰,价格也越高。 1k · 2k · 默认值: 1k
seed否用同一个数字,结果就能复现。 ≥ 0 · ≤ 2147483647
width否Output width in pixels when aspect_ratio is custom, 256 to 1024 (1024 if left out); height works the same way. The price still follows resolution. ≥ 256 · ≤ 1024

价格

价格以美元计。API 使用独立的美元余额。网站积分不能用于 API,也不能转入 API 余额;API 余额同样不能转为网站积分。 任务受理时,从 API 余额中冻结报价的最高金额;完成后按实际用量结算,实扣不超过冻结额,并释放剩余金额。任务失败则释放冻结额。

选项USD /张
resolution 1KUS$0.0192
resolution 2KUS$0.0768

运行前,将相同请求体发送到 POST /jobs/quote,可查看预计费用和最高费用,单位为美元。报价不会运行任务或扣款。

API 快速上手

三步调用 FLUX 3 Klein API

  1. 创建 API 密钥. 登录 PopNow,在 API 控制台创建密钥。密钥以 sk-popnow- 开头,API 调用使用独立的美元余额。
  2. 发送请求. 向 POST /jobs/createTask 发请求,model 填 black-forest-labs/flux-3-klein/edit,input 按参数表填写。响应会立刻返回任务 ID。
  3. 取回结果. 用任务 ID 轮询 GET /jobs/recordInfo,或者传 callBackUrl,结果会推送到这个地址。任务成功后下载输出链接。
# 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": "black-forest-labs/flux-3-klein/edit",
  "input": {
    "prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette",
    "image_urls": [
      "https://media.popnow.ai/influencer/examples/marco.webp"
    ],
    "aspect_ratio": "auto",
    "resolution": "1k",
    "output_format": "jpeg"
  }
}'

# 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"

请把提示词和链接换成你自己的。API 页签里有响应、轮询和回调的参考。

FLUX 3 Klein API 常见问题

FLUX 3 Klein API 怎么收费?

FLUX 3 Klein:最便宜的任务是编辑图片,US$0.0192/张起。各选项价格:1K US$0.0192/张、2K US$0.0768/张。API 使用独立的美元余额。网站积分不能用于 API,也不能转入 API 余额;API 余额同样不能转为网站积分。 任务受理时,从 API 余额中冻结报价的最高金额;完成后按实际用量结算,实扣不超过冻结额,并释放剩余金额。任务失败则释放冻结额。

FLUX 3 Klein · 编辑图片 API 有哪些限制?

分辨率:1K · 2K;画面比例:auto · 1:1 · 16:9 · 9:16 · 4:3 · 3:4 +11;参考图:10;提示词长度(字符):5,000;单个上传上限:10 MB。超出这些限制的请求会在扣费之前被拒绝。

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