Gravant Labs Upscale API

AI image upscaling with Real-ESRGAN + GFPGAN face enhancement

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Authentication

All requests require an API key in the header:

x-api-key: YOUR_API_KEY

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Endpoints

POST /api/v1/upscale

Upload and upscale an image.

Parameter	Type	Default	Description
file	file	required	JPEG, PNG, or WebP (max 10MB)
scale	2 | 4	2	Upscale factor
model	string	general-x4v3	general-x4v3 (fast) or x4plus (quality)
face_enhance	true | false	false	Enable GFPGAN face restoration

Example:

curl -X POST "https://upscale.gravantlabs.com/api/v1/upscale?scale=2&face_enhance=true"   -H "x-api-key: YOUR_API_KEY"   -F "file=@photo.jpg"

Response:

{
  "file_id": "a1b2c3-d4e5f6",
  "scale": 2,
  "face_enhance": true,
  "input_size": "400x600",
  "output_size": "800x1200",
  "processing_time": "3.5s",
  "download_url": "/api/v1/download/a1b2c3-d4e5f6",
  "expires_in": "1 hour"
}

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GET /api/v1/download/{file_id}

Download the upscaled image. Files expire after 1 hour.

curl -o result.png -H "x-api-key: YOUR_API_KEY"   https://upscale.gravantlabs.com/api/v1/download/a1b2c3-d4e5f6

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GET /api/v1/health

Check API status. No authentication required.

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Models

Model	Speed	Quality	Best for
general-x4v3	Fast (~3s)	Good	General use
x4plus	Slow (~10s)	Best	Maximum quality

face_enhance adds ~4s for GFPGAN face detection and restoration.

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Limits

Max file size	10 MB
Rate limit	30 requests / minute
File retention	1 hour
Formats	JPEG, PNG, WebP

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