Capture by Techulus - The ultimate toolkit for converting HTML to image & PDF. Pay only for what you need.No Subscription.
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
HTMLCSS to Image API - Convert HTML to an image (jpg, png, webp). Renders images exactly like Google Chrome. Works with PHP, JavaScript, Ruby, .NET and more.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Screenshot Machine - Screenshot machine is an online website capturing service. Creates a screenshot or thumbnail of any online web page in couple of seconds for free.
Better Uptime - We call you when your website goes down