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What is Synthetic Monitoring?

Synthetic monitoring uses scripted, simulated interactions to test your services proactively from multiple locations — 24 hours a day, 7 days a week. It detects outages, performance degradation, and broken functionality before your users encounter them.

Definition

Synthetic monitoring (also called active monitoring or proactive monitoring) is a technique that uses automated scripts to simulate user requests or transactions against your application at regular intervals. Tests run from external locations on a fixed schedule, providing consistent performance baselines and instant outage detection — independent of real user traffic.

For example, a synthetic monitor might make an HTTP GET request to your API every 60 seconds from 10 different locations, verify the response status code is 200, confirm the response body contains expected data, and measure the response time. Any deviation from expected behavior triggers an alert.

How Synthetic Monitoring Works

Synthetic monitoring follows a test-observe-alert cycle that runs continuously:

1Define Test Scripts

You configure what to test — an HTTP endpoint, a multi-step API flow, or a full browser-based transaction. You specify expected outcomes: response codes, content assertions, maximum response times, and header validations.

2Execute from Multiple Locations

Distributed agents run your tests from different geographic regions on a fixed schedule. Testing from multiple locations ensures you detect region-specific issues, CDN problems, and DNS propagation failures. AtomPing runs checks from multiple locations across Europe.

3Collect and Analyze Results

Each test run produces metrics: response time, time to first byte (TTFB), DNS lookup time, TLS handshake duration, and pass/fail status. These metrics are aggregated to establish baselines and detect anomalies.

4Alert on Failures or Degradation

When tests fail or performance degrades beyond thresholds, the system creates incidents and sends alerts via email, Slack, Discord, Telegram, or webhooks. Multi-region confirmation reduces false positives — a test failing from one location might be a network blip, but failures from multiple locations indicate a real problem.

Synthetic Monitoring vs Real User Monitoring (RUM)

These two approaches complement each other. Understanding their differences helps you build a complete monitoring strategy:

Aspect	Synthetic Monitoring	Real User Monitoring
Data Source	Scripted, simulated requests	Actual user sessions
Coverage	Fixed locations on a schedule	Every real user interaction
When It Works	24/7, even with zero traffic	Only when real users are active
Consistency	Controlled, reproducible tests	Variable (different devices, networks)
Strengths	Proactive detection, baselines, SLA validation	Real-world experience, edge cases, user impact
Weaknesses	Cannot capture every user scenario	Requires user traffic, privacy considerations

Key takeaway: Synthetic monitoring tells you "is my service working right now?" Real User Monitoring tells you "how are my users actually experiencing my service?" The best monitoring strategy uses both.

Types of Synthetic Tests

Synthetic monitoring encompasses a range of test types, from simple pings to complex multi-step transactions:

Availability Checks

The simplest form — send an HTTP request and verify the response. Check status codes, response times, and optionally validate content. This is the foundation of uptime monitoring.

API Monitoring

Test REST or GraphQL API endpoints with specific payloads, headers, and authentication. Validate response schemas, JSON paths, and status codes. Catches breaking changes and backend errors.

SSL/TLS Certificate Monitoring

Verify SSL certificate validity, expiration dates, and chain completeness. Certificate expiration is a common cause of preventable outages. Use our SSL Checker tool for an instant check.

DNS Monitoring

Verify DNS records resolve correctly and propagate consistently. Detects DNS hijacking, misconfigured records, and propagation delays that can make your service unreachable from certain locations.

Multi-Step Transaction Tests

Script complex user flows — login, search, add to cart, checkout — and verify each step completes successfully. These tests catch issues that simple availability checks miss, like broken forms or failed third-party integrations.

Benefits of Synthetic Monitoring

Synthetic monitoring provides several advantages that make it a foundational part of any monitoring strategy:

Proactive Issue Detection

Catch outages and degradation before users report them. Synthetic tests run 24/7, including off-peak hours when user traffic is low.

Performance Baselines

Controlled, repeatable tests from fixed locations establish consistent baselines. You can track performance trends and detect gradual degradation over time.

Global Visibility

Testing from multiple regions reveals regional performance differences, CDN issues, and geographic routing problems that affect subsets of your users.

SLA Validation

Synthetic monitoring provides the objective, third-party data needed to validate SLA compliance — proving your uptime to customers and stakeholders.

Third-Party Dependency Monitoring

Test critical third-party services (payment processors, CDNs, APIs) that your application depends on. Know when their issues affect your users.

Pre-Production Validation

Run synthetic tests against staging environments before deploying to production. Catch regressions in the deployment pipeline, not in production.

Multi-Region Synthetic Monitoring

Where you test from matters as much as what you test. Running synthetic checks from a single location only tells you half the story. Multi-region monitoring provides a complete view:

Detect CDN and DNS Issues

CDN misconfigurations and DNS propagation delays often affect only certain regions. A check from Frankfurt might succeed while Amsterdam fails. Multi-region testing catches these issues immediately.

Reduce False Positives

Network blips can cause a single check to fail momentarily. When checks from multiple regions confirm a failure, you can be confident it is a real outage — not a transient network issue between one probe and your server.

Measure Regional Performance

Response times vary by geography. Multi-region checks let you track performance from each location separately, helping you optimize CDN configuration, choose server locations, and identify regions where users experience poor performance.

Frequently Asked Questions

What is synthetic monitoring?▼

Synthetic monitoring is a proactive testing approach that simulates user interactions with your application from external locations at regular intervals. Unlike real user monitoring (RUM), which captures data from actual users, synthetic monitoring runs scripted tests 24/7 — even when no real users are active — to detect issues before they affect anyone.

What is the difference between synthetic monitoring and real user monitoring?▼

Synthetic monitoring uses scripted, simulated requests to test your service from known locations on a fixed schedule. Real User Monitoring (RUM) collects data from actual user sessions in real time. Synthetic monitoring provides consistent baselines and catches issues proactively, while RUM shows how real users actually experience your application, including diverse devices, networks, and locations.

What types of synthetic tests are there?▼

Common types include: availability checks (is the service up?), API monitoring (do API endpoints return correct responses?), multi-step transaction tests (can a user complete a login/checkout flow?), DNS resolution tests, SSL certificate checks, and page load speed tests. The simplest form is an HTTP ping; the most complex involves scripting full browser-based user journeys.

How does synthetic monitoring detect issues before users do?▼

Synthetic tests run continuously on a schedule — every 30 seconds, every minute, etc. — regardless of whether real users are on your site. If a test fails at 3 AM when user traffic is low, you are alerted immediately. Without synthetic monitoring, you might not discover the issue until morning when users start complaining.

Is synthetic monitoring enough on its own?▼

Synthetic monitoring is excellent for baseline availability and performance testing, but it does not capture the full diversity of real user experiences. Combining synthetic monitoring with RUM gives you the most complete picture — synthetic catches infrastructure issues proactively, while RUM reveals problems specific to certain browsers, devices, or geographic locations.

How many synthetic test locations do I need?▼

At minimum, use 2-3 locations to distinguish between regional and global outages. For services with a global user base, 5-10 locations across major regions provide good coverage. The key is to test from locations that represent your actual user base. More locations reduce false positives and give you better data on regional performance.

Related Glossary Terms

→Real User Monitoring (RUM)→Uptime Monitoring →Latency →Health Check →Throughput

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