The best APM tool depends on your stack and team: a developer-first tool suits small teams who want quick setup, an open source option suits teams who'd rather self-host, and a full observability suite suits large, complex systems. Ten options follow in no particular order.
Application performance monitoring tells you how your software behaves for real users: which pages are slow, which requests fail and where the time goes. Without it, you hear about problems from customers. With it, you often fix them before anyone notices.
The ten APM tools below are listed alphabetically and in no particular order, from open source options to suites used by large engineering teams. Every description comes from the vendor's own site, read this week. If your site's the main worry, my guide on how to speed up your website covers the quick wins first.
APM tools at a glance
In the free plan column, Yes means the tool's own site names a free plan, a free tier, a free portal or an open source edition. Trial only means a time-limited trial. Not stated means the pages I read named neither, even where there's a button inviting you to try it.
| Tool | Type | Good for | Free plan |
|---|---|---|---|
| AppSignal | Error tracking and performance monitoring | Small dev teams wanting quick setup | Yes |
| Datadog | Application performance monitoring | APM inside a wide monitoring suite | Trial only |
| Dynatrace | AI-powered observability platform | Large enterprise stacks | Trial only |
| Elastic Observability | APM on the Elastic platform | Troubleshooting distributed microservices | Trial only |
| Honeycomb | Observability platform | Debugging complex modern systems | Not stated |
| New Relic | Application monitoring platform | End-to-end visibility across services | Not stated |
| Raygun | Application monitoring for web and mobile | Crash reporting plus real user monitoring | Trial only |
| Scout Monitoring | Errors, logs and traces for developers | Feeding production errors to AI coding agents | Trial only |
| Sentry | Performance monitoring and error tracking | Developer-first error tracking | Not stated |
| SigNoz | Open source observability | Self-hosted, open source monitoring | Yes |
Ten APM tools to consider
AppSignal
Best for: Small development teams that want errors and performance monitoring together, with a free starting plan and a full trial.
Datadog
Best for: Engineering teams that already use Datadog for infrastructure and want application performance monitoring in the same place.
Dynatrace
Best for: Enterprises that want APM, distributed tracing and profiling for cloud-native and enterprise stacks, including AI apps.
Elastic Observability
Best for: Elastic users who want to spot anomalies and troubleshoot microservices, serverless functions and AI models.
Honeycomb
Best for: Software engineers who want observability built for debugging complex, modern systems, including multi-agent software and services.
New Relic
Best for: Teams that want end-to-end visibility across all their applications and services from one monitoring platform.
Raygun
Best for: Web and mobile teams that want crash reporting, real user monitoring and APM from one tool.
Scout Monitoring
Best for: Engineers using AI coding agents who want production errors, traces and performance data available to them.
Sentry
Best for: Developers who want error tracking and performance monitoring they can drop in with a few lines of SDK code.
SigNoz
Best for: Startups that want an open source alternative they can run on their own infrastructure or use as a cloud service.
Error tracking, APM or full observability?
Error tracking tools tell you when code breaks and show the stack trace. APM adds performance: slow requests, database queries and traces through your services. Full observability platforms bring metrics, logs and traces together across your whole infrastructure.
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A small team with one app often starts with error tracking plus basic APM. Teams running many services usually need tracing that follows a request from end to end.
Plan monitoring before launch
The GOV.UK Service Manual says teams should start planning how to monitor a service during alpha, agreeing what to monitor, how to monitor it and how to process and record issues.
It's good advice outside government too. Decide which user journeys matter most, what counts as slow and who gets the alert at night, before you launch. Retrofitting monitoring after the first outage always takes longer than doing it upfront.
Questions to ask APM vendors
- Which languages and frameworks in our stack do you support?
- How long does it take to see the first useful trace?
- Can we follow one request across several services?
- How do alerts avoid waking people up for nothing?
- Can we self-host, or is it cloud only?
- How does it connect errors to the release that caused them?
What to monitor first
- Key journeys. Sign-up, checkout and log-in.
- Error rates. Spikes after each release.
- Slow queries. The database is often the culprit.
- Third-party calls. Payment and email providers can stall.
Signs you've outgrown log files
If problems are found by customers first, developers spend hours reproducing bugs or nobody can say why last night was slow, it's time for APM. The first trace that pinpoints a slow query usually wins the team over. It's also worth agreeing who'll own the tool once it's installed, because dashboards nobody's responsible for don't stay useful for long, and alerts nobody's told about don't get answered.
Do you make APM tools? Tool makers can ask to be considered for a featured place on this list.
My plain advice on choosing an APM tool
Install two tools on a staging copy of your app for a week and see which one points you to a real problem fastest. The best APM tool is the one your developers open without being asked, because it gives answers rather than more charts.
Set a handful of clear alerts, such as error spikes and slow checkout pages, rather than dozens nobody reads. And watch what search engines see too, as Google Search Console's website performance reports show the outside view.
Frequently asked questions
What is an APM tool?
It's software that monitors how an application performs, tracking response times, errors and the path of requests through your code and services.
What's the difference between APM and observability?
APM focuses on application performance. Observability is broader, joining metrics, logs and traces so you can investigate problems across your whole system.
Are there free APM tools?
Yes. Some tools offer free plans or open source editions. Check the free plan column in the table for each one.
Do small websites need APM?
Simple brochure sites often don't. Web apps, online shops and software products usually benefit, as slow pages and errors lose customers.
What is distributed tracing?
It follows a single request as it passes through several services, so you can see exactly where time is spent or an error happens.
How do I stop alert fatigue?
Alert on what affects users, set sensible thresholds, route alerts to the right person and review noisy alerts regularly.
