Low web performance?
Try PRTG as website load tester

  • Monitor your website
  • Keep an eye on load times, processes, and content
  • Be alerted in the event of interruptions and errors
  • Webserver Stress Tool at no extra charge

Free Download
  • Unlimited version of PRTG for 30 days
  • After 30 days, PRTG reverts to a free version
  • Or, you can upgrade to a paid license anytime

Active load test vs. passive website monitoring

Active website load tests

Do you wish to deliberately test the load of your website? Or simulate pageviews and users and perform a stress test on your network bandwidth? Our Webserver Stress Tool can help. It will provide you with precise details on the breaking point of your website. The Webserver Stress Tool can be downloaded independently of PRTG. Please check beforehand whether your network can support it

The Webserver Stress Tool at a glance

Passive website monitoring

PRTG is a network monitoring tool. It lets you continually monitor your website, servers, and applications. When it comes to your website, you'll mainly monitor availability, load times, and processes. PRTG immediately sounds the alarm if the performance of your website drops. Its notification system can be customized to meet the specific needs of your company. Try PRTG for free and execute a web performance testing!

5 examples of monitoring with PRTG

Test the performance of your website with our Webserver Stress Tool

Das steckt drin

The tool

The Webserver Stress Tool is a software that can test an HTTP server to help you determine when the speed of your web server or applications is likely to suffer. How it works: the tool simulates hundreds or thousands of visitors, all of whom send HTTP requests to the server at the same time. This simulation will allow you to clearly and immediately identify the load at which your website performance begins to drop.

The amount of load it can generate

The amount of load it can generate

The Webserver Stress Tool can be tested at up to the following threshold values: approx. 500 mbps of bandwidth; one million pageviews per hour; 10,000 simultaneous users.

System requirements

System requirements

Please note: The Webserver Stress Tool has not been updated since 2014. At Paessler, we devote all our time to PRTG. You will not be able to use the Webserver Stress Tool to perform stress tests on SSL-encrypted pages. It will prove useful, however, for an internal network or other individual cases.

Why should I run a load testing tool?

Why should I run a load testing tool?

Often performance problems are hidden. At normal everyday loads, these problems are undetectable. Load and performance tests allow you to test the maximum availability and speed of your website. The tool’s diagrams are easy to understand. And to get started, you’ll only need a few minutes.

Example performance test


We’ve run an example performance test to give you an idea of how the tool works. Click on the links below for more detailed documents, graphs, and data.













Test Description

Probing the limits of a web server: Requesting a simple HTML page every 2 seconds in a ramp test 4,000 Details
In this test we wanted to see the difference between two web server programs on the same machine. 1,000 Details
In this test we are trying to find the maximum bandwidth a web server can serve.
100 Details



Test Description

UsersPageviewsBandwidth kbit/s 
Probing the limits of a server: Comparing request times of a static HTML file vs. a CGI Script 1300 ~78,000 ~750 Details
Megabit/Gigabit Upgrade for a Download Server: Comparing user experience of a download server connected to a 100MBit and a GigaBit network 250 ~46,000 downloads ~120,000 Details
Limits of a Download Server for Large Downloads: Probing the maximum number of users without deterioration of performance 100 ~6,400 downloads ~480,000 Details
Probing a Webserver with 3000 Users: Running a test with up to 3000 users against an IIS6 server 3,000 ~1,050,000 ~10,000 Details
Webserver Burn-In Test: Testing a server with constant load for 8 hours 3,000 ~1,070,000 ~15,000 Details
PHP Script Stress Test: Up to 500 users accessing a PHP script perpetually 500 ~326,000 ~30,000 Details
Comparing PHP Script Performance on Linux and Windows: Running two tests with different server OS on the same hardware 500 ~285,500 ~24,000 Details


Monitor the performance of your website with PRTG

PRTG at a glance

PRTG at a glance

PRTG keeps a constant eye on your entire IT infrastructure. With PRTG, you get a global overview of your network devices, website, bandwidth, servers, apps, virtual environments, and more. You’ll need around 10 sensors per device, or one sensor to monitor CPU, memory, the hard drive, and more. Licenses are determined by the number of sensors you will require.

PRTG monitoring

PRTG monitoring

The most basic version of PRTG is free of charge. You can use it to monitor a small network. All functions (including reports and the alarm) are included. If the time comes to expand your monitoring, simply choose the license that meets your needs. You can always upgrade your license later.

System requirements

System requirements

PRTG is a network monitoring tool for Windows systems. However, it can also be used with Linux-based networks. If you have a problem configuring or customizing your monitoring, our technical support team will be happy to help – and usually answers inquiries within 24 hours on weekdays. You can also find the answers to many questions in our knowledge base.

Why should I monitor my network?

Why should I monitor my network?

PRTG lets you keep a constant eye on the performance of your network. It promptly sends you an alert if your system malfunctions. This means you can go about your daily work with total peace of mind. Thanks to long-term analyses and reports, you can also monitor how your network load evolves.

The goal: 99.999 percent!

When it comes to the availability of your website, servers, and databases,
only one figure matters: 99.999. These “five nines” are indicative of the
high availability of your network.
PRTG helps you target this ambitious goal.

5 reasons to choose PRTG for your website monitoring


iWhat is a sensor?

In PRTG, “Sensors” are the basic monitoring elements. One sensor usually monitors one measured value in your network, e.g. the traffic of a switch port, the CPU load of a server, the free space of a disk drive. On average you need about 5-10 sensors per device or one sensor per switch port.

View video (3:26 min.)



Monitor availability with the HTTP Sensor

With the HTTP Sensor, you can see how long it takes to load an individual page. If the load time increases, you’ll be notified at once. The HTTP Advanced Sensor determines the download speed, or the “time to first byte.”

Packet Sniffing-Sensor

Obtain detailed load time data with the HTTP Full Web Page Sensor

How long does it take for the entire website to load? Which elements are slowing the page down? How do load times change over extended periods of time? Get the answers to these questions with the HTTP Full Web Page Sensor.

Cisco IP-SLA Sensor

Monitor content with the HTTP Content Sensor

The HTTP Content Sensor is an all-purpose sensor. It lets you monitor a variety of information, read the internal values of web applications (such as visitor numbers), or be notified if a page has been updated.

NetFlow Sensoren

Monitor order processes with the HTTP Transaction Sensor

It’s a long road from the first visit to the login screen, shopping cart, and confirmation page. It can be extremely frustrating to encounter errors or interruptions along the way. Monitor the functionality and processes of your website with the HTTP Transaction Sensor.

Ping Jitter Sensor

Monitor distributed networks with the Cloud HTTP v2 Sensor

Many companies have customers all over the world. Use the Cloud HTTP v2 Sensor and Cloud Ping v2 Sensor to check the availability of your website from each and every continent. Make sure your website is always up and running for customers around the globe.

An introduction to PRTG sensors

Trusted by 300,000 users
and recognized by industry analysts as a leader

“Fantastic network and infrastructure monitoring solution that is easy to deploy and easier still to use. Simply the best available.”

Read more reviews

“Software is absolutely perfect, Support is superior. Meets all needs and requirements, This is a must have solution if you are needing any form of monitoring.”

Read more reviews

“The tool excels at its primary focus of being a unified infrastructure management and network monitoring service.”

Read more reviews

  • Unlimited version of PRTG for 30 days
  • After 30 days, PRTG reverts to a free version
  • Or, you can upgrade to a paid license anytime

“Our network engineers really love PRTG, because of its customization”

John Krull, CTO, Oakland Unified School District, USA

Keep a constant eye on your network
– even while on the go

PRTG can be started within minutes and it's compatible with many mobile devices.


PRTG comes with all the features you need, plus more your IT infrastructure won't want to live without.


PRTG monitors these vendors and applications, and more, in one view!


PRTG is worth it: You’ll optimize your entire IT!

The costs for a one-year PRTG license usually pay for themselves within a few weeks.

PRTG improves the reliability of your network

PRTG improves the reliability of your network

PRTG saves network management costs

PRTG saves network management costs

PRTG saves time spent on network management

PRTG saves time spent on network management


What else can PRTG do? Keep reading!

Monitor traffic

Why is my system so slow? To answer this question, set up some customized traffic monitoring. You’ll discover how much bandwidth is being used by each of your devices and applications. SNMP monitoring gives you an overview. Packet sniffing and NetFlow monitoring analyze your traffic in detail.

Monitor websites

Want to take a closer look at your website? Find out the best way to configure your website monitoring. We offer a variety of tips and tricks to help you improve your load times. By the way, you can also monitor your WLAN with PRTG.

Monitor VoIP

When the firm’s VoIP goes down, the sysadmin and IT support team are immediately bombarded with calls. VoIP monitoring and QoS monitoring will help you ensure your VoIP is always up and running.  

ebook website performance

Want to speed up your website?

In our free ebook you learn everything about website performance indicators, the 3 levels of fitness, how your website gets in shape and how you monitor it.

Get your free copy of our website performance ebook now.

PRTG: The swiss army knife for sys admins

Adapt PRTG individually and dynamically to your needs relying on a strong API:

  • HTTP API: Access monitoring data and manipulate monitoring objects using HTTP requests
  • Custom Sensors: Create your own sensors for customized monitoring
  • Custom Notifications: Create your own notifications to send alarms to external systems
  • New REST API Sensor: Monitor almost everything that provides XML or JSON

Over 95% of our customers recommend PRTG


Paessler AG worldwide trialled PRTG in over 600 IT departments.
The aim was to tune the network monitoring software closer to the needs of the administrators.
The result of the survey: over 95% of the participants would recommend PRTG - or already had.

Recommend PRTG

German quality engineering




Free Download
  • Unlimited version of PRTG for 30 days
  • After 30 days, PRTG reverts to a free version
  • Or, you can upgrade to a paid license anytime

Most administrators want to test a tool for free before deciding to make an investment.

The many advantages of PRTG:

1. Free trial version: Take the time to explore PRTG so you can determine if it satisfies your needs and meets your expectations. Once the trial is over, it’s easy to upgrade your already configured version of PRTG, which means you’re much less likely to make an incorrect purchase.

2. One tool, one overview: Administrators often use a variety of monitoring solutions for their network or for the individual components of their infrastructure. But using several different tools every time you want to create an overview costs time and energy. PRTG is an “all-in-one” solution. Our dashboard and app provide a comprehensive overview, whenever you want it.

3. Quick customer support: Got a question? Stuck on a problem and need a hand? PRTG is backed by a dedicated development and support team. We do our utmost to answer every customer inquiry within 24 hours (on business days). Browse all our support topics here.

Configure your PRTG today. The trial version is free of charge. Save time, worry, and money with our monitoring tool designed for your network and entire infrastructure.



Network Monitoring Software - Version (October 20th, 2020)


Download for Windows and hosted version available


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Up to 100 sensors for free (Price List)

Unified Monitoring

Network devices, bandwidth, servers, applications, virtual environments, remote systems, IoT, and more

Supported Vendors & Applications


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