URL Structure

Complete reference for constructing imgfast CDN URLs.

link

Base URL

https://cdn.imgfast.io/{public_key}/{image_path}?{parameters}

cdn.imgfast.io

Our global CDN endpoint. All image requests go through this domain.

folder

Path Components

Component	Required	Description
`{public_key}`	Yes	Your account's public key (imgfast_pk_xxx)
`{image_path}`	Yes	Path to your uploaded image file

# Simple path
https://cdn.imgfast.io/pk_abc123/photo.jpg

# Nested path
https://cdn.imgfast.io/pk_abc123/products/2024/sneaker-01.jpg

# With transformations
https://cdn.imgfast.io/pk_abc123/hero-banner.jpg?w=1920&f=webp

tune

Query Parameters

Transformations are applied via query parameters. Multiple parameters are joined with &.

Category	Parameters	Link
Size	w, h, fit, g, ar, dpr	Resizing →
Format	f, q	Format →
Effects	blur, sharpen, brightness, contrast, saturation	Filters →
Watermark	wm_text, wm_image, wm_position	Watermark →
Security	sig, exp	Signed URLs ↓

public

Remote URL Proxy

Transform images from any URL without uploading. Add url/ before the remote URL.

https://cdn.imgfast.io/{public_key}/url/{remote_url}?{parameters}

# Example
https://cdn.imgfast.io/pk_abc123/url/https://example.com/photo.jpg?w=800&f=webp

security

Security Requirement

You must configure allowed domains in Settings → Allowed Domains. Only URLs from allowed domains will be processed.

verified_user

Signed URLs

Prevent unauthorized access and URL tampering with HMAC-signed URLs.

Parameter	Description
`sig`	HMAC-SHA256 signature
`exp`	Expiration timestamp (Unix seconds)

# Signed URL format
?w=800&exp=1735689600&sig=a1b2c3d4e5f6...

# Signature generation (pseudo-code)
path = "/pk_abc123/photo.jpg"
params = "w=800&exp=1735689600"
signature = HMAC-SHA256(signing_secret, path + "?" + params)

Generate Signed URLs

Node.js

import crypto from 'crypto';

function signUrl(path: string, params: Record<string, string>, secret: string) {
  const exp = Math.floor(Date.now() / 1000) + 3600; // 1 hour
  const queryString = new URLSearchParams({ ...params, exp: exp.toString() }).toString();
  const signature = crypto
    .createHmac('sha256', secret)
    .update(path + '?' + queryString)
    .digest('hex');

  return `https://cdn.imgfast.io${path}?${queryString}&sig=${signature}`;
}

// Usage
const signedUrl = signUrl(
  '/pk_abc123/photo.jpg',
  { w: '800', f: 'webp' },
  process.env.IMGFAST_SIGNING_SECRET
);