Why Synthetic Monitoring and End-to-End Testing Belong Together

Hannes Lenke
Checkly
Learn more about Checkly

Synthetic monitoring is crucial to deploy code with confidence as catching bugs with E2E tests on staging is becoming increasingly difficult. It isn't trivial to provide realistic staging systems, especially because today's apps are intertwined with many third-party APIs.

That's why nowadays, the low-hanging fruit is to set up checks that constantly monitor your production environment from an end-user perspective. This allows you to quickly find and fix issues on production before they become a problem for your customers. However, you need both testing in pre-production and monitoring on production.

Whether e-commerce shops or complex banking setups, systems are becoming increasingly intertwined and also distributed. They do not only rely on internal services but also on many external APIs such as payment APIs. It's nearly impossible to spin up production-like staging systems for these architectures. However, developers are, for many reasons, tasked to ship small pieces of new software numerous times a day. And this requires automation that ensures changes do not introduce bugs and break crucial flows while still delivering at speed and scale.

So on one side, we have complex systems that are nearly impossible to test fully in pre-production, and on the other, we have an increasing need for faster software delivery. These two things are like two trains on the same track heading for a collision. Thankfully, synthetic monitoring is here for the rescue!

But what is testing, and what is synthetic monitoring?

Let's look at synthetic monitoring and testing and what both could learn from each other. I'm sure ChatGPT can help us to define both terms:

Synthetic Monitoring

Synthetic monitoring tests and examines websites, applications, or services to ensure all components, including APIs, function as expected. It helps identify potential issues before they become a problem for the user or connected systems. It can be done from worldwide distributed remote locations. In simple terms, synthetic monitoring is having automated scripts checking your assets constantly to see if they are working correctly.

E2E testing

E2E testing helps to ensure the complete flow of an application or website works as expected before it gets deployed to production. It involves running tests to ensure all components work correctly from start to finish, as a real user would. In other words, it's like having an automated virtual tester check your web app to see if it works how it should.

Synthetics + Testing

In theory, synthetic monitoring and E2E testing are quite similar. While monitoring is meant to test your app on production constantly, E2E testing is intended to catch bugs before you deploy. The main difference in the past was that quality assurance (QA) teams performed testing while monitoring was the responsibility of operations (OPS), so the responsibility was split between two siloed teams. Not anymore!

Testing matured during the last decade from proprietary algorithms to open-source-based code hosted in your repository next to your application code. Today, cross-functional DevOps teams continuously run automated E2E tests in their CI/CD pipeline instead of isolated QA teams testing new versions of your app for three months before release.

Synthetic monitoring is also evolving similarly. It follows the transition E2E testing has already made: From proprietary scripts living in closed monitoring platforms to open-source-based scripts embedded in your repository. Monitoring is shifting left, as testing did, and is becoming integral to your developer's pipeline. The industry should encourage and enable developers to use the same scripts for pre-production tests and production monitoring. Doing so will blur the lines between E2E testing and synthetic monitoring.

So what does modern synthetic monitoring look like? Monitoring as code (MaC) is the next evolution of synthetic monitoring. To be successful in a MaC approach, we need to look at three essential pillars that make up the MaC concept: code, test, and deploy:

1. Code: Automated tests are defined as code and live in a repository, often close to your application code. When I write code, I mean code, not just configuration files saved in a repository. With that approach, MaC enables flexibility and programmability, allowing you to test your backend and UI by supporting complex API and browser checks.

2. Test: Synthetic monitoring was traditionally meant to run on production only. Now, checks as code enable us to run all or some of these checks locally and in a CI/CD flow to be tested on staging before a new version gets deployed. Monitoring is becoming testing, and testing is becoming monitoring, blurring the lines between the two.

3. Deploy: The main difference between testing and monitoring is scheduling. MaC enables us to schedule our tests, executing these constantly, 24/7, in distributed remote locations worldwide. In other words, your tests are deployable. In addition, deploying your tests via your CI/CD process allows monitors to be updated with application code changes.

Synthetic monitoring has been evolving quickly during the last months. We see many exciting approaches to enable developers to ensure that their apps are reliable and resilient. Monitoring as code is the only logical next step, as it has many advantages and enables you to reuse your tests.

Hannes Lenke is CEO and Co-Founder of Checkly

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Why Synthetic Monitoring and End-to-End Testing Belong Together

Hannes Lenke
Checkly
Learn more about Checkly

Synthetic monitoring is crucial to deploy code with confidence as catching bugs with E2E tests on staging is becoming increasingly difficult. It isn't trivial to provide realistic staging systems, especially because today's apps are intertwined with many third-party APIs.

That's why nowadays, the low-hanging fruit is to set up checks that constantly monitor your production environment from an end-user perspective. This allows you to quickly find and fix issues on production before they become a problem for your customers. However, you need both testing in pre-production and monitoring on production.

Whether e-commerce shops or complex banking setups, systems are becoming increasingly intertwined and also distributed. They do not only rely on internal services but also on many external APIs such as payment APIs. It's nearly impossible to spin up production-like staging systems for these architectures. However, developers are, for many reasons, tasked to ship small pieces of new software numerous times a day. And this requires automation that ensures changes do not introduce bugs and break crucial flows while still delivering at speed and scale.

So on one side, we have complex systems that are nearly impossible to test fully in pre-production, and on the other, we have an increasing need for faster software delivery. These two things are like two trains on the same track heading for a collision. Thankfully, synthetic monitoring is here for the rescue!

But what is testing, and what is synthetic monitoring?

Let's look at synthetic monitoring and testing and what both could learn from each other. I'm sure ChatGPT can help us to define both terms:

Synthetic Monitoring

Synthetic monitoring tests and examines websites, applications, or services to ensure all components, including APIs, function as expected. It helps identify potential issues before they become a problem for the user or connected systems. It can be done from worldwide distributed remote locations. In simple terms, synthetic monitoring is having automated scripts checking your assets constantly to see if they are working correctly.

E2E testing

E2E testing helps to ensure the complete flow of an application or website works as expected before it gets deployed to production. It involves running tests to ensure all components work correctly from start to finish, as a real user would. In other words, it's like having an automated virtual tester check your web app to see if it works how it should.

Synthetics + Testing

In theory, synthetic monitoring and E2E testing are quite similar. While monitoring is meant to test your app on production constantly, E2E testing is intended to catch bugs before you deploy. The main difference in the past was that quality assurance (QA) teams performed testing while monitoring was the responsibility of operations (OPS), so the responsibility was split between two siloed teams. Not anymore!

Testing matured during the last decade from proprietary algorithms to open-source-based code hosted in your repository next to your application code. Today, cross-functional DevOps teams continuously run automated E2E tests in their CI/CD pipeline instead of isolated QA teams testing new versions of your app for three months before release.

Synthetic monitoring is also evolving similarly. It follows the transition E2E testing has already made: From proprietary scripts living in closed monitoring platforms to open-source-based scripts embedded in your repository. Monitoring is shifting left, as testing did, and is becoming integral to your developer's pipeline. The industry should encourage and enable developers to use the same scripts for pre-production tests and production monitoring. Doing so will blur the lines between E2E testing and synthetic monitoring.

So what does modern synthetic monitoring look like? Monitoring as code (MaC) is the next evolution of synthetic monitoring. To be successful in a MaC approach, we need to look at three essential pillars that make up the MaC concept: code, test, and deploy:

1. Code: Automated tests are defined as code and live in a repository, often close to your application code. When I write code, I mean code, not just configuration files saved in a repository. With that approach, MaC enables flexibility and programmability, allowing you to test your backend and UI by supporting complex API and browser checks.

2. Test: Synthetic monitoring was traditionally meant to run on production only. Now, checks as code enable us to run all or some of these checks locally and in a CI/CD flow to be tested on staging before a new version gets deployed. Monitoring is becoming testing, and testing is becoming monitoring, blurring the lines between the two.

3. Deploy: The main difference between testing and monitoring is scheduling. MaC enables us to schedule our tests, executing these constantly, 24/7, in distributed remote locations worldwide. In other words, your tests are deployable. In addition, deploying your tests via your CI/CD process allows monitors to be updated with application code changes.

Synthetic monitoring has been evolving quickly during the last months. We see many exciting approaches to enable developers to ensure that their apps are reliable and resilient. Monitoring as code is the only logical next step, as it has many advantages and enables you to reuse your tests.

Hannes Lenke is CEO and Co-Founder of Checkly

Related Links

Hot Topics

Related Vendors

The Latest

Manufacturing Organizations Doubled AI Investment Yet Only 37% Fully Prepared to Operationalize AI

While 87% of manufacturing leaders and technical specialists report that ROI from their AIOps initiatives has met or exceeded expectations, only 37% say they are fully prepared to operationalize AI at scale, according to The Future of IT Operations in the AI Era, a report from Riverbed ...

Optimizing Decisions with Edge-First Cognitive Intelligence

Many organizations rely on cloud-first architectures to aggregate, analyze, and act on their operational data ... However, not all environments are conducive to cloud-first architectures ... There are limitations to cloud-first architectures that render them ineffective in mission-critical situations where responsiveness, cost control, and data sovereignty are non-negotiable; these limitations include ...

The New Perimeter Is the User: Why Identity Is the Real Network Edge

For years, cybersecurity was built around a simple assumption: protect the physical network and trust everything inside it. That model made sense when employees worked in offices, applications lived in data centers, and devices rarely left the building. Today's reality is fluid: people work from everywhere, applications run across multiple clouds, and AI-driven agents are beginning to act on behalf of users. But while the old perimeter dissolved, a new one quietly emerged ...

When AI Infrastructure Stops Behaving Like Infrastructure

For years, infrastructure teams have treated compute as a relatively stable input. Capacity was provisioned, costs were forecasted, and performance expectations were set based on the assumption that identical resources behaved identically. That mental model is starting to break down. AI infrastructure is no longer behaving like static cloud capacity. It is increasingly behaving like a market ...

Enterprise Resilience: Understanding the Shift from Static to Dynamic

Resilience can no longer be defined by how quickly an organization recovers from an incident or disruption. The effectiveness of any resilience strategy is dependent on its ability to anticipate change, operate under continuous stress, and adapt confidently amid uncertainty ...

Mobile Users Expect Perfection in 2026

Mobile users are less tolerant of app instability than ever before. According to a new report from Luciq, No Margin for Error: What Mobile Users Expect and What Mobile Leaders Must Deliver in 2026, even minor performance issues now result in immediate abandonment, lost purchases, and long-term brand impact ...

AI Confidence Is High. Readiness Is Not. What the Data Tells Us - and Why It Matters

Artificial intelligence (AI) has become the dominant force shaping enterprise data strategies. Boards expect progress. Executives expect returns. And data leaders are under pressure to prove that their organizations are "AI-ready" ...

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Agentic AI is a major buzzword for 2026. Many tech companies are making bold promises about this technology, but many aren't grounded in reality, at least not yet. This coming year will likely be shaped by reality checks for IT teams, and progress will only come from a focus on strong foundations and disciplined execution ...

Trust, But Verify: Building Confidence in AI Through Human Oversight

AI systems are still prone to hallucinations and misjudgments ... To build the trust needed for adoption, AI must be paired with human-in-the-loop (HITL) oversight, or checkpoints where humans verify, guide, and decide what actions are taken. The balance between autonomy and accountability is what will allow AI to deliver on its promise without sacrificing human trust ...

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