Home
APIs
Image & Vision
AI Image Generation API

Image & Vision API

AI Image Generation API

Turn text prompts into visuals and mockups. You only pay for images that are actually generated.

POST https://rsflowhub.com/api/v1/ai/image-generation

120 credits per call
X-API-Key header
JSON in, JSON out

Try it in the playground API reference

POST /api/v1/ai/image-generation

{
    "prompt": "A futuristic city skyline at sunset, cyberpunk style.",
    "size": "1024x1024"
}

200 OK response.json

{
    "result": {
        "images": [
            {
                "url": "https://rsflowhub.com/storage/generated/20261019/img_7c1e9a40d2b84f63a1c5e8d07b9f2a6c41de3b58.jpg",
                "mime_type": "image/jpeg",
                "width": 1024,
                "height": 1024,
                "expires_at": "2026-10-26T10:30:00+00:00"
            }
        ]
    }
}

Definition

What is the AI Image Generation API?

AI Image Generation API is a REST API on RSFlowHub for web, mobile and AI agent applications. Send a JSON request to POST /api/v1/ai/image-generation with your API key; RSFlowHub runs it on a tuned AI model, falls back to a backup provider if needed, and returns a structured JSON result, usually within 1 to 3 seconds.

Category: Image & Vision
Endpoint: POST /api/v1/ai/image-generation
Authentication: X-API-Key header
Price: 120 credits per call
Rate limit: 10 to 120 requests / minute by plan
Typical response: 1 to 3 seconds
Format: JSON, UTF-8

Request parameters

Send these fields as a JSON body. An invalid or missing field returns a 422 error that names the field.

Field	Type	Required	Description
`prompt`	string	Required	Image generation prompt (Max: 4,000 chars)
`style`	string	Optional	Visual style, e.g. "photorealistic", "illustration", "3d_render"
`aspect_ratio`	string	Optional	Image shape: "1:1", "3:2", "2:3", "3:4", "4:3", "4:5", "5:4", "9:16", "16:9" or "21:9". Default is "1:1".
`size`	string	Optional	Older way to pick the shape, e.g. "1024x1024" or "1024x1792": mapped to the closest aspect ratio. Images are always about 1 megapixel. Ignored when aspect_ratio is set.
`n`	integer	Optional	Number of images to generate (1 to 4). Each generated image is billed separately.

Code examples

Copy, replace rfh_your_api_key with your key and run. Prefer a client library? See the official SDKs.

request.sh

curl -X POST "https://rsflowhub.com/api/v1/ai/image-generation" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: rfh_your_api_key" \
  -d '{"prompt":"A futuristic city skyline at sunset, cyberpunk style.","size":"1024x1024"}'

client.php

<?php

$client = new \GuzzleHttp\Client();
$response = $client->post('https://rsflowhub.com/api/v1/ai/image-generation', [
    'headers' => [
        'Content-Type' => 'application/json',
        'X-API-Key'    => 'rfh_your_api_key',
    ],
    'json' => array (
      'prompt' => 'A futuristic city skyline at sunset, cyberpunk style.',
      'size' => '1024x1024',
    ),
]);

echo $response->getBody();

client.js

const response = await fetch('https://rsflowhub.com/api/v1/ai/image-generation', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'X-API-Key': 'rfh_your_api_key'
  },
  body: JSON.stringify({"prompt":"A futuristic city skyline at sunset, cyberpunk style.","size":"1024x1024"})
});

const data = await response.json();
console.log(data);

main.py

import requests

url = "https://rsflowhub.com/api/v1/ai/image-generation"
headers = {
    "Content-Type": "application/json",
    "X-API-Key": "rfh_your_api_key"
}
payload = {"prompt":"A futuristic city skyline at sunset, cyberpunk style.","size":"1024x1024"}

response = requests.post(url, json=payload, headers=headers)
print(response.json())

Response

Every RSFlowHub endpoint uses the same envelope, so one parser handles all of them. Failed calls are not charged.

response.json

{
    "success": true,
    "request_id": "req_3f9a2c7e-5b1d-4e8a-9c2f-7d6e1a0b4c8d",
    "data": {
        "result": {
            "images": [
                {
                    "url": "https://rsflowhub.com/storage/generated/20261019/img_7c1e9a40d2b84f63a1c5e8d07b9f2a6c41de3b58.jpg",
                    "mime_type": "image/jpeg",
                    "width": 1024,
                    "height": 1024,
                    "expires_at": "2026-10-26T10:30:00+00:00"
                }
            ]
        }
    },
    "meta": {
        "version": "v1",
        "timestamp": "2026-10-05T09:30:00Z"
    }
}

error.json

{
    "success": false,
    "request_id": "req_8c1d4e2a-7f3b-4a9c",
    "error": {
        "code": "VALIDATION_ERROR",
        "message": "The given data was invalid.",
        "details": {
            "prompt": [
                "This field is required."
            ]
        }
    },
    "meta": {
        "version": "v1",
        "timestamp": "2026-10-05T09:30:00Z"
    }
}

Envelope fields
Field	Type	Meaning
`success`	boolean	true when the call worked, false on any error.
`request_id`	string	Unique id for this call. Quote it when you contact support.
`data.result`	object	The result of this endpoint (see the example).
`error`	object	Only on failure: code, message and details per field.
`meta`	object	API version and server timestamp.

All error codes: Errors reference

Features

Photorealistic & Vector Styling

Render photorealistic photos, 3D renders, cyberpunk art, or minimalist vector illustrations on demand.

Custom Aspect Ratios & Resolutions

Generate assets in 1:1 (square), 16:9 (landscape), 9:16 (mobile story), 4:3, 3:2, 21:9 and more, at about 1 megapixel (1024x1024 for square).

Safety Filter Built In

Prompts blocked by the safety filter return HTTP 422 CONTENT_BLOCKED and cost no credits.

Ready-to-use Image URLs

Each image comes back as an HTTPS URL with its size, type and expiry time. Download it within 7 days.

Use cases

How teams use the AI Image Generation API in production.

Publishing & Media

Dynamic Blog & Article Header Art

Generate bespoke header visuals matching article topics upon content publication.

Input: Editorial illustration of a high-speed neural network routing data packets across servers.
Output: https://rsflowhub.com/storage/generated/img_8f9a2b1c.jpg

Creates unique article images without stock photo licensing.

E-Commerce

E-Commerce Product Mockup Staging

Stage products into realistic lifestyle backgrounds (e.g., modern living room, kitchen table).

Input: Coffee mug placed on a rustic wooden desk with warm morning sunlight.
Output: https://rsflowhub.com/storage/generated/img_mug_lifestyle.jpg

Accelerates product merchandising without booking expensive studio photo sessions.

Social Advertising

Social Media Ad Variant Generation

Produce 10+ visual creative variations for Facebook and Instagram A/B ad testing.

Input: SaaS dashboard preview with glowing neon charts on dark glass background.
Output: https://rsflowhub.com/storage/generated/img_ad_variant_3.jpg

Decreases customer acquisition costs (CAC) by identifying winning visual creatives.

AI Image Generation API vs building it yourself

The same job done three ways.

Topic	RSFlowHub API	Raw LLM prompts	Rules / regex
Output	Validated JSON fields	Free text you have to parse	Fixed patterns only
Setup	One POST request, no prompts	Write and maintain prompts and parsing	Write and maintain rule lists
Provider outage	Automatic fallback to a backup model	You build retries and a second vendor	Not applicable
Pricing	120 credits per call, failed calls free	Per token, per vendor	Your own servers and upkeep
Understands context	Yes, AI model	Yes, AI model	No, keywords only

Frequently asked questions

What image formats and resolutions are returned by the API?

Each image is returned as an HTTPS URL to an image file (usually JPEG; the response gives its mime_type) of about 1 megapixel (1024x1024 for 1:1, other aspect ratios keep a similar pixel count). URLs stay available for 7 days, so download and store the images you want to keep.

How long does image generation take?

Usually a few seconds per call. When you ask for several images they are generated in parallel. Set your HTTP client timeout to at least 60 seconds.

Who owns the images generated through the API?

RSFlowHub does not claim ownership of images you generate. You are responsible for how you use them under our Terms. Generated images carry an invisible digital watermark that marks them as AI-generated.

What happens if a prompt violates safety filters?

The request returns HTTP 422 with the error code CONTENT_BLOCKED and no credits are charged.

How many credits does an image generation call consume?

150 credits per generated image, plus 1 credit per image for every 1,000 prompt characters. If you ask for 4 images and only 3 are generated, you pay for 3. Image generation needs a paid plan.

Start using the AI Image Generation API

Free plan with 100 credits/month + 1,000 bonus credits when you sign in before 23 Nov. Test it in the playground first, no code needed.

Get a free API key Try it now