Uptime.com

Pingdom is an uptime monitoring service. When problems happen with a site that Pingdom monitors, it immediately alerts the owner so the problem can be taken care of.

It is all about helping you to keep your websites up. It monitors your websites every 5 minutes and alerts you if your sites are down.

Better Stack is a radically better infrastructure monitoring platform that calls the right person on your team if anything goes wrong. Schedule on-call duties, receive helpful alerts, and collaborate on solving incidents faster than ever.

Monitoring a website is one thing – finding the best way to alert you to downtime another. At StatusCake we give you as many options as possible to decide when & how often you’re contacted. Whether it’s by email, SMS, push notifications for iOS & Android or integration with third party apps including Zapier and PagerDuty – you decide how you want to be alerted and when!

updown is an online service that checks your website's status by periodically sending an HTTP HEAD request to the URL of your choice. It then notifies you by email or sms when your website is not responding correctly.

Site24x7 is an all-in-one monitoring solution that allows you to monitor every part of your IT infrastructure from Websites to Applications, to Servers (both on-premise and on the cloud) as well as your Network infrastructure.

It is a self-hosted, open-source, fancy uptime monitoring, and alerting system. It can monitor HTTP, HTTP with keywords, TCP, Ping, and even DNS systems!

It gives you insight on how well your site loads and provides actionable recommendations on how to optimize it. It is a free tool that analyzes your page's speed & performance.

It is an all in one uptime monitoring tool which monitors your URL from 10 locations around the globe ensuring that if your website ever goes down again, you get alerted within 60 seconds. It comes with advanced capabilities like SSL Monitoring, Advanced Alerting and more.

Checkly is the API & E2E monitoring platform for the modern stack: programmable, flexible and loving JavaScript. Free for developers!

It is an easy way to track the uptime & SSL health for your websites & apps. It's website monitoring without the hassle. Multi-location uptime monitoring, mixed content detection and SSL certificate & transparency reporting. There's an API and kick-ass documentation too.

It provides website and server availability monitoring. At its most basic, the service lets users enter a list of addresses of web site addresses or other Internet based services, and then checks to see if that site or service is responding properly

AlertBot's Website Monitoring provides businesses with around the clock testing of their website pages. This monitoring includes the testing of all possible webpage failure points as well as the verification of key performance metrics. This data gives businesses the information they need to ensure their websites are always running error-free and providing a quality user experience.

WebGazer is a monitoring service that checks your website, cron jobs or scheduled tasks on a regular basis. It notifies you with instant alerts in case of a problem.

It monitors your website, dashboards, API's, and more and alerts your team when downtime happens. We also give you a Status Page which keeps your customers looped in and improves transparency.

web-alert.io is a simple uptime and API monitoring service built for developers, indie hackers, and small SaaS teams who want clear, reliable alerts without enterprise complexity. It monitors websites and API endpoints, sends instant downtime alerts, checks SSL certificates, and tracks response times — all inside a clean, minimal dashboard. Setup takes under a minute, and there’s a free plan included. Perfect for small projects, micro-SaaS, client sites, and devs who just want to know when something is down.

Modern uptime and performance monitoring for websites and APIs, with rich reporting, flexible alerting, and competitive pricing. More than just HEAD requests: choose an HTTP method, headers, and body for any request.

It provides improvement points to locate the source of problems in hidden areas that were not found in other products.

Website performance monitoring, simplified for small teams. It's not a expensive APM "solution" or a complex query language to learn. It is the key metrics you need to know to keep your website running fast and your customers happy.

When it comes to downtime, seconds count. We monitor your site around-the-clock to make sure it never skips a beat. We offer HTTP, HTTPS, RUM, DNS, ICMP, IMAP, POP3, SMTP, TCP, UDP, and Transaction monitors.

Pingbreak is an original and free monitoring service. Get notified if your website is down. Pingbreak checks all of your websites each minute and alert you instantly by Direct Message on Twitter, WebHook, Discord channel, Slack or Mattermost.

Picreel converts website visitors to customers with custom popups, advanced targeting, segmentation, and A/B testing for maximum campaign optimization.

Receive alerts when your website or API is down through emails, Slack or SMS, integrated with real time data and insights

It is a command line application to monitor every part of your web app using a simple JSON configuration file. Get alert not only when your site is down but also when it's slow.

It is a web monitoring tool that keeps you up to date and up to speed. If you're looking to keep track of updates on any website or social platform, it is the tool you need.

It is an Infrastructure monitoring as a service for public/private cloud, on-prem and hybrid environments. Built for SaaS, e-commerce, service providers and enterprise.

Using our stories feature, you can test many different features of your live, production website. It could be you need to find out if logins are working. Whatever it is, StillAlive can (or will) be able to test it.

Whether you have one site, or twenty, Vigil is a simple and reliable service for monitoring the uptime and performance of your websites. View all your sites on our beautiful client dashboards, get email and push notifications when there is a problem, and receive weekly email summary reports that let you know how your sites are doing over the long-term.

AI-powered web page monitoring with support for HTML and JS-rendered pages. Get instant alerts and readable summaries of what changed.

Speed is not just important for ranking in Google but also important for your website visitors and for your conversion metrics. Know the speed of your web page and make it better. SpeedFactor features easy-to-use data reports, visualisations, graphs and charts, notifications and alerts, powered by Google Lighthouse and a properietary security suite. Traditional web performance metrics are often technical and don’t reflect your customer’s journey. SpeedFactor uses a mix of Google Lighthouse and proprietary auditing and focuses on user experience metrics.

It is a powerful tool for ensuring the availability of your websites and servers. You can easily keep track of your online assets and receive alerts when there are any issues or disruptions.

It is a Pingdom/Cronitor free alternative, but the other way around and A LOT simpler, with A LOT more capabilities, suitable for developers, system admins, DevOps, and individuals with complex networking situations.

It is a web-based service that monitors the availability and loading speed of any website, server, network, basically any network asset you grant access to. After failure detection, it alerts you in numerous ways. It's most distinguishable service is its transaction monitoring and custom scrips.

Monitor website changes and send the latest data to IFTTT, Google Sheets, Zapier, Firebase, AWS Lambda and many other services.

It is a web analysis tool that can analyze all pages of your websites in one dashboard and monitor them with your team.

It is a fully featured Website Monitoring Software designed to serve Enterprises, Startups. It provides end-to-end solutions designed for Web App. This online Website Monitoring system offers Performance Metrics, Availability Testing, Uptime Reporting at one place.

It provides insights into the security, modernity, and performance of any website's technology stack and guidance to improve web vitals and tech stack.

It regularly scans your SSL certificates to check for any errors such as a past-due expiry date and common misconfigurations. Trusted by nearly 2,000 users to track close to 20,000 certificates.

It is a one-click website testing tool used by federal agencies, Fortune 100 corporations, and independent consultancies.

It provides policy-based management, minimizes downtime in case of disasters via automated orchestration, and enables nondisruptive testing of your disaster recovery plans.