Which image model? Start with
flux-2-klein (0.03,fastest).Use‘flux−kontext−max‘(0.10) for best quality. Use flux-kontext-pro ($0.05) for image editing. Compare all →Request
POST https://www.ninjachat.ai/api/v1/images
Authorization: Bearer nj_sk_YOUR_API_KEY
Content-Type: application/json
{
"model": "flux-2-klein",
"prompt": "A golden retriever puppy in autumn leaves, soft lighting, photorealistic",
"size": "1920x1920",
"n": 1
}
Response
{
"model": "flux-2-klein",
"images": [
{
"url": "https://cdn.example.com/generated-abc123.webp",
"revised_prompt": "A golden retriever puppy in autumn leaves..."
}
],
"usage": { "images_generated": 1 },
"cost": {
"this_request": "$0.03",
"per_image": "$0.03",
"images": 1
},
"metadata": { "latency_ms": 1847, "size": "1920x1920" }
}
images[0].url. Download it or display it directly.
Parameters
| Parameter | Type | Required | Default | Description |
|---|---|---|---|---|
prompt | string | Yes | — | What you want. Be specific — style, lighting, composition. Max 4,000 chars. |
model | string | No | nano-banana-2 | Which model. See table below. |
size | string | No | 1920x1920 | 1920x1920 (square), 2560x1440 (landscape), 1440x2560 (portrait) |
n | integer | No | 1 | Number of images (1–4). Each billed separately. |
image | string | No | — | Reference image URL for image-to-image. Must be public HTTPS. |
Models
| Model | ID | Cost | Speed | Best for |
|---|---|---|---|---|
| FLUX Kontext Max | flux-kontext-max | $0.10/img | ~5-15s | Premium editing, max fidelity |
| FLUX.2 Flex | flux-2-flex | $0.08/img | ~5-10s | Maximum quality generation |
| FLUX.1 Pro Ultra | flux-1-pro-ultra | $0.08/img | ~8-15s | Ultra-high resolution (4MP) |
| Recraft V3 | recraft-v3 | $0.08/img | ~5s | Design, illustrations |
| Google Imagen 4 | google-imagen-4 | $0.08/img | ~15s | Photorealism, text rendering |
| Nano Banana Pro | nano-banana-pro | $0.08/img | ~5s | Professional assets, thinking mode |
| Seedream | seedream | $0.08/img | ~8s | Realistic, artistic styles |
| FLUX.2 Pro | flux-2-pro | $0.05/img | ~3-5s | Balanced quality/speed |
| FLUX Kontext Pro | flux-kontext-pro | $0.05/img | ~5s | Image editing, style transfer |
| Nano Banana 2 | nano-banana-2 | $0.05/img | ~3s | Best value, text rendering |
| FLUX.1 Fill | flux-1-fill | $0.05/img | ~5s | Inpainting, outpainting |
| FLUX.2 Klein | flux-2-klein | $0.03/img | <2s | Fastest, batch processing |
| Nano Banana | nano-banana | $0.03/img | ~2s | Fast, budget-friendly |
Not ready to write code? Try this in the API Playground →
Full working examples
import os, requests
HEADERS = {"Authorization": f"Bearer {os.environ['NINJACHAT_API_KEY']}"}
def generate_image(prompt, model="flux-2-klein", size="1920x1920"):
r = requests.post("https://www.ninjachat.ai/api/v1/images",
headers=HEADERS,
json={"model": model, "prompt": prompt, "size": size}
)
r.raise_for_status()
return r.json()["images"][0]["url"]
# Quick draft ($0.03, <2s)
url = generate_image("A mountain landscape at sunset")
print(url)
# High quality final ($0.08, ~5-10 seconds)
url = generate_image("A mountain landscape at sunset, 8k, ultra detailed",
model="flux-2-flex", size="2560x1440")
print(url)
async function generateImage(prompt, model = "flux-2-klein", size = "1920x1920") {
const r = await fetch("https://www.ninjachat.ai/api/v1/images", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.NINJACHAT_API_KEY}`,
"Content-Type": "application/json",
},
body: JSON.stringify({ model, prompt, size }),
});
if (!r.ok) throw new Error(`${r.status}: ${await r.text()}`);
return (await r.json()).images[0].url;
}
const url = await generateImage("A mountain landscape at sunset");
console.log(url);
Image-to-image
Transform an existing image by passing its URL:r = requests.post("https://www.ninjachat.ai/api/v1/images",
headers=HEADERS,
json={
"model": "flux-kontext-pro",
"prompt": "Turn this into a watercolor painting with soft colors",
"image": "https://example.com/my-photo.jpg" # Must be public HTTPS
}
)
print(r.json()["images"][0]["url"])
Multiple images
Generate up to 4 variations in one request:r = requests.post("https://www.ninjachat.ai/api/v1/images",
headers=HEADERS,
json={
"model": "recraft-v3",
"prompt": "Logo for a coffee shop called 'Bean There', minimal vector",
"n": 4
}
)
for i, img in enumerate(r.json()["images"]):
print(f"Variation {i+1}: {img['url']}")
# Cost: 4 × $0.08 = $0.32
Prompt tips
Be specific. Compare:| Weak | Strong |
|---|---|
dog | Golden retriever puppy sitting in autumn leaves, soft golden hour lighting, shallow depth of field, photorealistic |
city | Cyberpunk cityscape at night, neon signs reflecting in rain puddles, aerial view, cinematic lighting, 8k |
logo | Minimal vector logo for a tech startup, geometric shapes, blue and white, clean lines, flat design |