Registration is open - Live, Instructor-led Online Classes - Elasticsearch in March - Solr in April - OpenSearch in May. See all classes

What Is Synthetic Monitoring

Learn everything about synthetic monitoring and testing: how it works and why you need it to improve web transaction and application performance. A complete tutorial for Devs.

Website performance is a key component of the success of your website or application. Having a website that is performing well regardless of location, load, or connection type is no longer a best practice but rather a requirement.

Monitoring web transactions can be done in many ways but one of the most popular ways out there is synthetic monitoring. To help you get started, in this guide we'll walk you through everything you need to know about it, from what is synthetic monitoring and why do we need it to how it works, use cases, and the different types you can use to improve website and application performance.


Synthetic monitoring, also known as synthetic testing, active or proactive monitoring, is an application performance monitoring practice that uses scripted recordings of a series of requests and emulates them to simulate the user's interactions with your website or application. In a nutshell, it helps you understand your user's experience and improve website performance by predictive behavior.

Synthetic performance monitoring involves running constant tests to provide information about critical business transactions, applications availability, website speed, and much more.

Synthetic monitoring tools help answer questions like:

  • Is the site or app up and running?
  • How fast is my site at this moment?
  • Are the 3rd Part APIs still operating?
  • What's your CPU/Memory Utilisation look like?
  • Do the Server hardware components have any faults?

What Is the Difference Between Synthetic Monitoring and RUM

There are two ways to monitor application and website performance: real user monitoring and synthetic monitoring.

Synthetic Monitoring, or synthetic transaction monitoring, uses a series of scripts that will simulate the interactions between the user and server tracking response time, response codes, etc.

By comparison, Real User Monitoring (RUM), is a passive form of monitoring that tracks the interactions between the site and actual users instead of emulating them. There's a little javascript code that gets added to the site and that will record every transaction and interaction between the end-user and server.

Usually, there's no real reason that you should have to choose either synthetic monitoring or real user monitoring as both of them have their own merits. While synthetic monitoring solutions help track short-term issues, real user monitoring tools such as Sematext Experience can show you long-term performance trends; synthetic monitoring solutions will let you know and understand what to expect in terms of user experience but real user monitoring will show you exactly what happened.

For debugging purposes, RUM and Synthetic do solve a very different problem but many people use them together since that's a sure-fire way to ensure peak app and website performance. For example, an issue that was first spotted in RUM as a result of user interaction can be further investigated in Synthetics by monitoring individual endpoints and services.

If you're interested in learning more about the differences between these two, check out our post about Real user monitoring vs. Synthetic monitoring or our short video tutorial:

How Does Synthetic Monitoring Work

Synthetic monitoring works by simulating a web transaction between a virtual client and your application or website in order to simulate what a typical user interaction might look like. These emulated transactions are triggered by different operating systems and locations across the world to test and collect data on availability, response time, downtime, and errors.

Each transaction is triggered at a specific interval and it will run a predefined test that aims to replicate a user's interaction with the website as closely as possible. This will help you create a solid baseline of your application and further understand any weaknesses or limitations you might need to address.

Since they take up little resources, synthetic performance monitoring tools can run 24/7 during peak hours when the website is crawling with users and it's quiet. This is especially important since simulating end user's interactions through basic navigation and actions can help you test new features and modules you are developing in different scenarios and at different times during the day.

Why Do You Need It: Synthetic Testing Use Cases

Synthetic monitoring enables you to see and test your website and applications from your end users' perspectives. Furthermore, you'll know where and when the performance drops or if there will be any type of issues affecting their experience.

But let's dive deeper and see what are the advantages of using synthetic performance monitoring.

why use synthetic monitoring

Fix performance issues before they affect your end users

With synthetic monitoring, you emulate user interactions and run a set of tests from different locations across the world. It will keep an eye on all your APIs, web and mobile applications, and all your websites regardless if you have real users on the site. The purpose of synthetic performance monitoring is to find issues before your users do. Sematext comes out of the box with specific Dashboards and Alerts that can be configured to start monitoring key aspects of your infrastructure and trigger whenever things start to go sideways.

Read our guide to alerting and monitoring to learn more about why you need to monitor and set up alerts in the first place.

Benchmark your website

You can set up your synthetic monitoring solutions to look at your APIs from different locations at different times during the day. Then use this data as a baseline for your benchmarks as it helps you identify parts of the system that need further work, while also serving as a means to compare your service with your competition. We have this step-by-step tutorial on how to benchmark website performance if you want to learn more.

Test your scaling capabilities

You build your website and applications to respond quickly to your users but when traffic grows unexpectedly, your server needs to be able to respond in kind. Synthetic performance monitoring allows you to run artificial tests that show how your server will react under load. Once you have this data you can think of the necessary steps you'll have to take to ensure your site and apps scale gracefully.

Test new product features before launching

Synthetic monitoring is a great tool to have when you're launching new features since it allows you to run a full set of tests before having them go Live during peak hours. You'll be able to see how the rest of the application reacts under load and if any of the recent changes will impact a 3rd party API you might be using.

Monitor third-party APIs and critical business processes

It's pretty difficult not to use any third-party tools in your business but that exposes you to a series of problems related to their availability. You need to keep a close eye on them and get a heads up the second things start to slow down. However, monitoring API metrics is not enough to ensure you are delivering a top-notch experience for your users. You'll want to make sure the mission-critical components of your application, like logging in, searching or checkout are working as expected.

Ensure SLA compliance

It doesn't matter what side of the SLA you are sitting on – making sure that everyone involved in the contract is adhering to the agreement is critical for both parties. If you happen to be the service provider you'll want to use synthetic monitoring tools to make sure you understand the performance limitations of your application and set realistic expectations. If you are the customer you'll want to make sure that the vendor can hold up to his part of the deal.

Reduce MTTR

By using synthetic monitoring software like Sematext Synthetics, you can greatly reduce your MTTR by having an alert sent out to the relevant people even before the issue starts affecting your users. Not only will you be alerted sooner, but you'll also have a clearer understanding of what's causing the issue and how to replicate it.

Different Types of Synthetic Monitoring

There's a long list of synthetic monitoring types that can help you achieve these benefits but here are the main ones.

what does synthetic monitoring include

Uptime Monitoring

Uptime monitoring is the most common type of monitoring and perhaps the most basic one out there. It describes the general availability of a website and it's usually measured in percentages. To put things into perspective a 99.999% uptime availability is what's considered good and even that will result in your website being down around 5 minutes every year.

Uptime monitors work by sending a simple request to the desired endpoint at a predefined interval and reporting back on the result. You use this metric to figure out if your website is available for your users.

This is where you'll want to use uptime monitoring software like Sematext Synthetics to set up alerts for different scenarios for when either the website is down altogether or the resources are taking too long to load.

Web Performance Monitoring

With so many options available, your users require their favorite website or application to perform the best so having a service that underperforms is going to negatively affect your business. This is where website monitoring comes into play.

Dedicated website performance monitoring tools allow you to create complex networks of monitors for all your resources and key website metrics to ensure your users are getting the absolute best experience.

API Monitoring

Both your internal and external APIs play a crucial role in the success of your website or application, so monitoring APIs to make sure they are working as expected is going to be imperative for your business.

With a synthetic monitoring approach, you'll be able to identify underperforming APIs before they impact your users' experiences. It provides everything you need to know about the bottleneck, allowing you to get to the bottom of it in no time.

Synthetic Transaction Monitoring

Synthetic transaction monitoring is a proactive website monitoring method that usually involves having a script that would simulate a user's interaction through the website.

Having a way to simulate clicks and swipes can help you optimize your strategy and act as an early warning system that will alert you when a part of the process is not functioning as intended.

Transactions monitoring is extremely efficient in online stores and similar websites, where the users follow a usual path through, and every deviation, delay, or error can cause them to abandon the purchase.

HTTP Monitoring

HTTP monitors will ping your web pages from different checkpoints located around the world and report back on their availability. Besides just checking in, you'll also get information on load speed and HTTP status codes but if you choose to use more advanced tools like Sematext Synthetics you'll also be able to set up complex HTTP requests and monitor their response.

synthetic monitoring use cases

Browser Monitoring

Browser monitoring is a technique used to emulate different browsers' performance while loading your website and application to make sure you can deliver the ideal user experience.

Since websites and apps use a large number of frameworks and third-party APIs you'll want to make sure they all work in perfect harmony regardless of the operating system or browser your users are using. We run these checks from different machines in different corners of the world and report back on load speed, availability, HTTP codes, and if something breaks you'll be alerted immediately.

How Sematext Can Help

Getting started with Sematext Synthetics is very easy and doesn't require any code modifications to be made on your website. It allows you to create monitors for each individual resource that you want to track and once you have a baseline you can create certain alerts to be triggered when the criteria for them are met.

Our synthetic monitoring tool helps you collect data about the total response time, see detailed response time split by DNS lookup, connected time and time to the first byte, HTTP response codes, downtime, availability, and many other website performance metrics. All this data is then displayed in easy-to-read dashboards that give you a clear birds-eye-view of your entire website performance. Furthermore, they provide you with enough data to be able to debug and identify the root cause of your issues in no time.

Every synthetic transaction is triggered from multiple locations we have set up around the world at a variable interval that can be configured to be either 1m, 5m, 10m, or 15m. This gives you granular control over how often these tests run and if need be they can be paused altogether.

Read our blog post about Sematext Synthetics or watch this short video to learn more about how the tool works.

Get Started with Synthetic Monitoring

It's worth mentioning that while synthetic monitoring tests help you simulate user interactions through various scenarios, the end-user experience can reflect a totally different story altogether. Things that affect your users' interaction with the website like geolocation distribution, device, and operating system, connection speed, etc. won't be reflected in the reports. To get data on these you'll have to use a real user monitoring tool.

Sematext has two very good options for both synthetic and real user monitoring that will help you paint a clear picture of what your overall website performance looks like and how satisfied are your users with using your service. If you don't know how to pick the best synthetic monitoring tool for your use case, our colleague explains it in this video.

If you want the best of both worlds, you should look for website monitoring tools that combine the power of synthetic monitoring and RUM. Or go further for an all-in-one solution to get end-to-end visibility of your apps and services such as Sematext Cloud, our cloud monitoring tool that brings logs, metrics, events, and traces under one roof.