Convert HTML to Image in Ruby

require "net/http"
require "json"

html = <<~HTML
  <div style="padding:48px;background:#0f172a;color:white;
             font-family:sans-serif;border-radius:12px;width:800px">
    <h1>Social Card</h1>
    <p style="color:#94a3b8">Developer profile image</p>
  </div>
HTML

uri  = URI("https://renderpix.dev/v1/render")
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true

req = Net::HTTP::Post.new(uri)
req["X-API-Key"]    = "rpx_your_key"
req["Content-Type"] = "application/json"
req.body = { html: html, width: 800, height: 400, format: "png" }.to_json

res = http.request(req)
File.write("card.png", res.body, mode: "wb")