black-forest-labs/flux-2-klein-4b-lora/edit4 點數起 /張· 編輯圖片FLUX.2 Klein 4B LoRA 執行 Black Forest Labs 小巧的開源 FLUX.2 Klein 4B,可載入最多三個你自己的 LoRA 檔案,大約四秒出圖。文生圖有九種比例,最大 2048 畫素,改圖最多用三張原圖。
在 POST /jobs/createTask 把模型名稱填成 black-forest-labs/flux-2-klein-4b-lora/edit 就能呼叫,4 點數/張起(US$0.04)。新帳戶送 30 點數,可以先在 Playground 免費試用。
- 生成圖片
- 編輯圖片
- 最高 2K
- 最多 3 張參考圖
- 9 種畫面比例
- 可載入自己的 LoRA
black-forest-labs/flux-2-klein-4b-lora/editPOST https://api.popnow.ai/api/v1/jobs/createTask# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(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: $IDEMPOTENCY_KEY" \
-d '{
"model": "black-forest-labs/flux-2-klein-4b-lora/edit",
"input": {
"prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette",
"image_urls": [
"https://media.popnow.ai/influencer/examples/marco.webp"
],
"aspect_ratio": "auto",
"resolution": "1k"
}
}'
# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
-H "Authorization: Bearer $POPNOW_API_KEY"// Node 18+ (or any runtime with fetch). Keep the API key on your server.
const BASE = "https://api.popnow.ai/api/v1";
const headers = { Authorization: `Bearer ${process.env.POPNOW_API_KEY}` };
const sleep = (ms) => new Promise((r) => setTimeout(r, ms));
async function call(path, init = {}) {
const res = await fetch(BASE + path, { ...init, headers: { ...headers, ...init.headers } });
const body = await res.json();
if (body.code !== 200) throw new Error(`${body.code} ${body.msg}`);
return body.data;
}
const { taskId } = await call("/jobs/createTask", {
method: "POST",
headers: { "Content-Type": "application/json", "Idempotency-Key": crypto.randomUUID() },
body: JSON.stringify({
"model": "black-forest-labs/flux-2-klein-4b-lora/edit",
"input": {
"prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette",
"image_urls": [
"https://media.popnow.ai/influencer/examples/marco.webp"
],
"aspect_ratio": "auto",
"resolution": "1k"
}
}),
});
// Poll with backoff. A finished task may still be copying files: wait while an asset is pending.
let task;
for (let delay = 2000; ; delay = Math.min(delay * 1.5, 15000)) {
await sleep(delay);
task = await call(`/jobs/recordInfo?taskId=${taskId}`);
const copying = (task.output?.assets ?? []).some((a) => a.pending && !a.unavailable);
if (["succeeded", "failed", "canceled", "expired"].includes(task.state) && !copying) break;
}
if (task.state !== "succeeded") throw new Error(`${task.state}: ${task.errorMessage ?? "no detail"}`);
// Each asset has a signed url (no API key needed) that expires at expiresAt: save the file.
for (const asset of task.output.assets) console.log(asset.url);import os, time, uuid, requests
BASE = "https://api.popnow.ai/api/v1"
HEADERS = {"Authorization": f"Bearer {os.environ['POPNOW_API_KEY']}"}
def call(method, path, **kwargs):
body = requests.request(method, BASE + path, headers={**HEADERS, **kwargs.pop("headers", {})}, timeout=30, **kwargs).json()
if body["code"] != 200:
raise RuntimeError(f'{body["code"]} {body["msg"]}')
return body["data"]
task_id = call(
"POST",
"/jobs/createTask",
headers={"Idempotency-Key": str(uuid.uuid4())}, # reuse it if you retry
json={
"model": "black-forest-labs/flux-2-klein-4b-lora/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"
}
},
)["taskId"]
# Poll with backoff. A finished task may still be copying files: wait while an asset is pending.
delay = 2.0
while True:
time.sleep(delay)
task = call("GET", "/jobs/recordInfo", params={"taskId": task_id})
assets = (task.get("output") or {}).get("assets") or []
copying = any(a.get("pending") and not a.get("unavailable") for a in assets)
if task["state"] in ("succeeded", "failed", "canceled", "expired") and not copying:
break
delay = min(delay * 1.5, 15.0)
if task["state"] != "succeeded":
raise RuntimeError(f'{task["state"]}: {task.get("errorMessage", "no detail")}')
# Each asset has a signed url (no API key needed) that expires at expiresAt: save the file.
for asset in assets:
print(asset["url"])input 依下方的 Schema 產生,原樣就能通過驗證。把提示詞和連結換成你自己的即可。
價格
| 選項 | 點數 /張 | ≈ 美元 |
|---|---|---|
| 標準 | 3.06 | US$0.031 |
1 點數 = $0.01 · 全部選項及價格:GET /models/black-forest-labs/flux-2-klein-4b-lora/edit
每個任務會無條件進位到整數點數,所以最低檔跑一次是 4 點數/張(US$0.04)。
限制
- 解析度
- 1K · 2K
- 畫面比例
- auto · 1:1 · 16:9 · 9:16 · 4:3 · 3:4 +4
- 參考圖
- 3
- 提示詞長度(字元)
- 5,000
- 單一上傳上限
- 10 MB
參數
這些欄位來自我們驗證每個請求所用的同一份 Schema。沒列出的欄位會被拒絕。
promptstring必填Say what to change and what must stay the same. Put a LoRA trigger phrase first.
image_urlsarray<string>必填要編輯或合成的照片。在提示詞裡說明每張的用途。
aspect_ratiostring選填畫面形狀:橫式、方形或直式。
resolutionstring選填輸出尺寸。越大越清晰,價格也越高。
lorasarray<object>選填載入你自己的 LoRA,鎖定風格或角色。
內部欄位
loras[].pathstring必填Direct URL of a LoRA weights file.
loras[].scalenumber必填Weight strength from zero to four.
seedinteger選填用同一個數字,結果就能重現。
原始 JSON Schema
{
"additionalProperties": false,
"properties": {
"aspect_ratio": {
"default": "auto",
"description": "Output aspect ratio; auto keeps the shape of the first source image.",
"enum": [
"auto",
"1:1",
"16:9",
"9:16",
"4:3",
"3:4",
"3:2",
"2:3",
"21:9",
"9:21"
],
"type": "string"
},
"image_urls": {
"description": "One to three source images, in the order your prompt refers to them.",
"items": {
"contentMediaType": [
"image/jpeg",
"image/png",
"image/webp",
"image/gif"
],
"format": "uri",
"minLength": 1,
"type": "string"
},
"maxItems": 3,
"minItems": 1,
"type": "array"
},
"loras": {
"default": [],
"description": "Up to three LoRA weight files trained for FLUX.2 [klein] 4B or FLUX.2 [klein] Base 4B, each with its own strength.",
"items": {
"additionalProperties": false,
"properties": {
"path": {
"contentMediaType": [
"application/octet-stream"
],
"description": "Direct URL of a LoRA weights file.",
"format": "uri",
"minLength": 1,
"type": "string"
},
"scale": {
"default": 1,
"description": "Weight strength from zero to four.",
"maximum": 4,
"minimum": 0,
"type": "number"
}
},
"required": [
"path",
"scale"
],
"type": "object"
},
"maxItems": 3,
"type": "array"
},
"prompt": {
"description": "Say what to change and what must stay the same. Put a LoRA trigger phrase first.",
"maxLength": 5000,
"minLength": 1,
"type": "string"
},
"resolution": {
"default": "1k",
"description": "Output size tier when you choose an aspect ratio; with auto the result keeps the shape of the first source image.",
"enum": [
"1k",
"2k"
],
"type": "string"
},
"seed": {
"description": "Random seed for controlled comparisons.",
"maximum": 2147483647,
"minimum": 0,
"type": "integer"
}
},
"required": [
"prompt",
"image_urls"
],
"type": "object"
}FLUX.2 Klein 4B LoRA 的真實成品

Colored pencil hyperdetailed realism. Redraw this photo as a colored pencil drawing at blue hour: the diner windows now show a cobalt dusk sky, the lights inside are warm, and the top buttons of her yellow shirt-dress are undone as she leans on the counter with her chin on her hand, smiling at the viewer. Keep her face and hair.
{
"model": "black-forest-labs/flux-2-klein-4b-lora/edit",
"input": {
"prompt": "Colored pencil hyperdetailed realism. Redraw this photo as a colored pencil drawing at blue hour: the diner windows now show a cobalt dusk sky, the lights inside are warm, and the top buttons of her yellow shirt-dress are undone as she leans on the counter with her chin on her hand, smiling at the viewer. Keep her face and hair.",
"image_urls": [
"https://media.popnow.ai/influencer/examples/marco.webp"
],
"aspect_ratio": "auto",
"resolution": "1k",
"seed": 28843
}
}這則是從上傳的檔案開始的:把範例連結換成你自己的檔案連結。
回應、輪詢與回呼
所有模型的用法都一樣:先建立任務,再輪詢,或等待回呼。
先報價
curl -X POST https://api.popnow.ai/api/v1/jobs/quote \
-H "Authorization: Bearer $POPNOW_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "black-forest-labs/flux-2-klein-4b-lora/edit",
"input": {
"prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette",
"image_urls": [
"https://media.popnow.ai/influencer/examples/marco.webp"
],
"aspect_ratio": "auto",
"resolution": "1k"
}
}'請求內容和 createTask 相同。它回傳預估扣款和最高可能扣款,不會真的執行。
已受理
HTTP/1.1 202 Accepted
{
"code": 200,
"msg": "success",
"data": {
"taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
"state": "queued"
},
"request_id": "req_example_create"
}HTTP 202 代表任務已受理,點數先凍結、尚未扣除。最終扣款不會超過凍結額。
查詢狀態
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
-H "Authorization: Bearer $POPNOW_API_KEY"每隔幾秒查詢一次並逐步拉長間隔,state 變成 succeeded、failed、canceled 或 expired 時停止。
完成的任務
{
"code": 200,
"msg": "success",
"data": {
"taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
"model": "black-forest-labs/flux-2-klein-4b-lora/edit",
"state": "succeeded",
"output": {
"assets": [
{
"url": "https://cdn.popnow.ai/tasks/task_01k3m8x9q2z4v7n5p6r8s0t1w3/output.png?signature=FROM_RESPONSE",
"expiresAt": "2026-10-17T12:20:00Z",
"mime": "image/png",
"width": 1024,
"height": 1024
}
]
},
"settled": true
},
"request_id": "req_example_record"
}請在 expiresAt 之前從 url 下載。之後需要新連結,請呼叫 POST /common/download-url。
驗證回呼
import { createHash, createHmac, timingSafeEqual } from "node:crypto";
import express from "express";
const app = express();
// express.raw keeps the exact bytes that were signed; express.json would not match.
app.post("/hooks/popnow", express.raw({ type: "application/json" }), (req, res) => {
const timestamp = req.header("X-Webhook-Timestamp");
const signature = req.header("X-Webhook-Signature") ?? "";
const body = JSON.parse(req.body.toString("utf8"));
const taskId = body.data?.taskId ?? body.task_id;
const digest = createHash("sha256").update(req.body).digest("hex");
const expected = createHmac("sha256", process.env.POPNOW_WEBHOOK_SECRET)
.update(`${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
});設定 callBackUrl 後,我們會把完成的任務送給你。先用原始請求內容驗證簽名,再信任它。
上傳本機檔案
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.公開的 https 連結可以直接用。本機檔案要先經過 upload-url 和 commit。

