Features of Alertra Website Uptime Monitoring

Overview - Site Uptime Monitor by Alertra

We monitor websites for site uptime and virtually anything else connected to the internet 24/7 using a global network of independent nodes. We send alerts by email of course, but our most popular features are Phone Call and SMS alerts which we send just about anywhere in the world. There is no software to install and we begin monitoring as soon as you create your account. Since starting up in the year 2000, we've built a reputation of reliability, accuracy and speed. Our systems are always available, our platform is designed from the ground up to eliminate false alerts, and we detect outages faster than anyone else.

Website Uptime Monitoring - Key Features

Global Network.

We do uptime monitoring from locations around the world in the North America, Europe and Asia/Pacific regions. Our monitoring "nodes" are fully capable servers located in carrier-class data centers such as Equinix and Telehouse.


We check web servers several times a minute to make sure they're accepting socket connections. The impact on server and bandwidth is virtually undetectable. But if you lose your connection or run out of server resources, Synapse provides an unparalleled early detection mechanism. Honestly, we catch a very large percentage of outages this way and we catch them in seconds, regardless of the protocol monitoring interval you have selected.

See how it works

False Alerts: We don't do it.

We wait for consecutive failures from three different locations before we send an alert. Our monitoring nodes operate completely independently from each other, sharing no information. These design characteristics ensure that it's virtually impossible for us to send a false alert.

DNS Caching: We don't do it, either.

Most monitoring services simply rely on the DNS lookup facility of the underlying O/S. That means they won't recognize outages related to DNS until the TTL (time-to-live) expires, which could be hours or even days. We don't cache DNS lookups, we do a fresh lookup every time. That means we detect these outages as soon as they begin.


Most of our customers simply need us to monitor uptime of a website URL, but we also have native monitors for many other popular internet protocols (HTTP, DNS, SMTP, POP3, etc.). For obscure or custom services, we can monitor the socket itself using TCP.

See the full list

Custom Script.

When you need more than standard up/down monitoring, we can monitor your multi-step process (login, web transaction, end-to-end email, etc.) using a custom script.

ASL Documentation


You can schedule maintenance in advance, or you can start/stop maintenance on demand. Either way, we don't monitor uptime or send alerts during maintenance.

More info

Detailed Response Time.

We break down the HTTP request/response so you can see each component: DNS lookup time, SSL handshake time (if present), socket connect time, time-to-first-byte (TTFB) and time-to-last-byte (TTLB). This is invaluable when you're trying to determine why your response time is slow. For example, a long TTFB means your server is taking too long to build the response page.

Packet Capture.

When you really need to dig deep, we provide the actual packet capture from every monitoring check we do. The packet capture can be downloaded and viewed using Wireshark, giving you the ultimate visibility into the interaction between our monitoring node and your server.


We send alerts by email, phone call, SMS and chat (XMPP). We also support custom contact methods like iOS/Android push notifications using Pushover.net and external logging/alerting services like PagerDuty. If it has an API, we can create a custom contact for it. Escalation. We give you complete control over how your contacts are notified during an outage. For example, send email and SMS alerts first, and if the outage persists, start waking people up with phone calls.

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Organize your monitored devices with user-defined tags. Start/stop maintenance for devices tagged "Servers." Send a weekly uptime monitoring report by email for devices tagged "Critical." Publish a public status page for devices tagged "Public."


With event-driven webhooks, we go a lot further than just sending you an alert, we take action. When you have site uptime issues and your site goes down, we can call an external API to switch your DNS to a backup site, log the event to an external logging service, and just about anything else you can think of.

More Info


The fully functional, HTTP-based application programming interface to our services. Make our Alertra your Alertra. It's as simple as:

PUT /devices/<YOUR_DEVICE_ID>/start-maintenance?api_key=<YOUR_API_KEY>
"Duration": "01:00"

More Info on our API

Public Uptime Statistics

You’ve worked hard to build a stable, reliable system with good site uptime. Now it’s time to show off those uptime statistics.

Not sure? Try before you buy!

We're so confident you'll love Alertra's comprehensive website monitoring services, we'll let you try it for a month - for free!

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