API Documentation

Generate favicons and OG images programmatically. Free tier: 5 requests/day. Pro: unlimited.

Base URL

https://og.hjlabs.in

OG Image Generation

GET /api/og

Generate an OG image via URL parameters. Returns SVG image.

Parameter	Type	Description
title	string	Main title text (required)
subtitle	string	Subtitle text
author	string	Author name
template	string	Template: default, blog, product, social, minimal, nature
brand	string	Brand text (top-left)
bg	hex color	Custom background color
color	hex color	Custom text color
accent	hex color	Custom accent color

Example:

https://og.hjlabs.in/api/og?title=My+Blog+Post&template=blog&brand=mysite.com

POST /api/og

Generate via JSON body. Same parameters as GET.

{
  "title": "My Blog Post",
  "subtitle": "A deep dive into...",
  "template": "blog",
  "brand": "mysite.com"
}

Favicon Generation

POST /api/generate-favicon

Generate a favicon ZIP with all sizes. Returns application/zip.

Field	Type	Description
type	string	letter, text, emoji, gradient, or upload
letter	string	Single character (for letter/gradient type)
text	string	1-3 characters (for text type)
emoji	string	Emoji character (for emoji type)
bgColor	hex	Background color
textColor	hex	Text/letter color
color1	hex	Gradient start color
color2	hex	Gradient end color
shape	string	rounded or circle (gradient type)
siteName	string	For manifest file generation
imageData	base64	Data URL of uploaded image

Example (curl):

curl -X POST https://og.hjlabs.in/api/generate-favicon \
  -H "Content-Type: application/json" \
  -d '{"type":"letter","letter":"H","bgColor":"#3b82f6","textColor":"#fff"}' \
  -o favicons.zip

GET /api/favicon-preview

Generate a single favicon preview as SVG. Useful for live previews.

Parameter	Type	Description
type	string	letter, text, emoji, gradient
letter	string	Character to display
bg	hex	Background color
color	hex	Text color
size	number	Output size in pixels (default: 256)

Rate Limits

Plan	Favicon ZIP	OG Images	Preview SVG
Free	10/day	50/day	100/day
Pro ($12/mo)	Unlimited	10K/mo	Unlimited
Agency ($29/mo)	Unlimited	Unlimited	Unlimited

Response Codes

Code	Description
200	Success
400	Bad request (missing/invalid parameters)
429	Rate limit exceeded
500	Server error