# Real-ESRGAN - Core.Today AI API

> The classic image upscaler (94M+ runs). Real-ESRGAN super-resolution up to 10x with optional GFPGAN face enhancement — the go-to default for cleanly enlarging photos and AI images.

- **Provider**: Real-ESRGAN
- **Model ID**: nightmareai/real-esrgan
- **Category**: Image Generation
- **Credits**: 5 per image
- **Speed**: Fast
- **Quality**: High

## Features
- Battle-tested upscaler (94M+ runs)
- Scale factor up to 10x
- Optional GFPGAN face enhancement
- Faithful, artifact-free enlargement
- Very low cost (6 credits per image)

## Use Cases
- Upscaling AI-generated images
- Enlarging photos for print
- Restoring low-resolution assets
- Thumbnail to full-size conversion
- Batch resolution normalization

## API Endpoint

Base URL: https://api.core.today/v1
Create Prediction: POST /predictions
Get Status: GET /predictions/{job_id}

## Authentication
Header: X-API-Key: YOUR_API_KEY

## Input Parameters

### Required
- **image**: string - Input image to upscale

### Optional
- **scale**: number (default: 4) - Factor to scale the image by (up to 10)
- **face_enhance**: boolean (default: false) - Run GFPGAN face enhancement along with upscaling

## Examples

### 4x Photo Upscale
Standard 4x upscale of a photo
```json
{
  "model": "nightmareai/real-esrgan",
  "input": {
    "image": "https://example.com/photo.jpg",
    "scale": 4
  }
}
```

### Portrait Upscale with Face Enhancement
Upscale a portrait and restore facial details
```json
{
  "model": "nightmareai/real-esrgan",
  "input": {
    "image": "https://example.com/portrait.jpg",
    "scale": 2,
    "face_enhance": true
  }
}
```

## Response Format
```json
{
  "job_id": "abc123",
  "status": "pending | processing | completed | failed",
  "result": "URL or data (when completed)"
}
```

## Usage Flow
1. POST /predictions with model and input -> receive job_id
2. GET /predictions/{job_id} -> poll until status is completed or failed
3. Result contains output URL(s)

## Tips
- scale 4 is the sweet spot; very large scales on big images can slow down or fail
- Enable face_enhance for portraits — it runs GFPGAN on detected faces
- For faithful enlargement use this; for re-imagined detail use Clarity Upscaler
- Great as a post-processing step after fast image models like SDXL Lightning

## Documentation
https://replicate.com/nightmareai/real-esrgan