Best Open Source Application Monitoring Tools in 2026

Application Performance Monitoring tools track the performance of applications in real-time but also analyze it in context and in time to spot anomalies and performance-related issues. Open Source Application Performance Monitoring tools give a lot of freedom to their users since they can access and customize the tool's source code for project-specific needs. It also allows for self-hosting, which can help in the context of tightening data protection laws. They also often offer a vibrant community of active developers who might provide helpful plugins and tips.

The market is saturated with free and open-source APM tools, but picking the right one for your stack might be tricky. Let's take a look at some of the most reliable and community-approved open-source application performance tools in 2026.

1. Prometheus

Prometheus is an open-source monitoring and alerting set of tools built by SoundCloud's engineers in 2012. It was the second CNCF project after Kubernetes, and it has managed to obtain a large and vibrant community of contributors and users ever since.

2. Graphite

Graphite is here to kick ass, chew bubble gum and make it easy to store and graph metrics. It's an enterprise-ready monitoring tool optimized for extensive cloud infrastructure and cheap, budget servers. Graphite was initially built at Orbitz, which released it under an open-source Apache 2.0 license and adapted it as their main monitoring framework.

3. Jaeger

Built by Uber and then donated to CNCF, Jaeger is a Dapper-inspired, distributed tracing system allowing you to monitor and troubleshoot microservice-based distributed systems. Jaeger supports two open-source NoSQL database backends: Cassandra and Elasticsearch. Jaeger allows you to perform root cause analyses, analyze server dependencies, optimize performance and latency and monitor transactions.

4. Signoz

SigNoz is an MIT-licensed, open-source alternative to many APM tools. It's a full-stack observability tool allowing you to monitor metrics and traces, with Log management on the way. SigNoz supports OpenTelemetry for instrumentation and offers out-of-the-box charts and visualizations. It runs on either Kafka+Druid or OLAP database ClickHouse for the backend. The Query service is built-in GO, and the front-end is Typescript-powered.

5. The ELK Stack

Elastic APM is built upon the ELK stack. It's composed of open source libraries for collecting performance data, a server, receiving performance data, Elasticsearch, and Kibana for visualization. The ELK Stack is one of the most popular data processing stacks.

6. MiniProfiler

Muniprofiler is a simple monitoring tool for .NET, Ruby, Go, and Node.js apps. It allows you to profile ASP.NET, ASP.NET Core, EF Core, Entity Framework 6, and SQL Server. It's available on GitHub.

7. Apache Skywalking

Apache Skywalking is an All-in-one APM solution for distributed systems, made for microservices, cloud-native and container-based architectures. Skywalking is lightweight, scalable, and supports alerting and visualization features. Skywalking has more than 600 contributors on GitHub and has thousands of contributions every year.

Skywalking is built for Java .NET core, PHP, Node.js, Golang, LUA, Rust, and C++ agents and all of these agents are actively maintained.

9. Stagemonitor

Stagemonitor is an open-source Java application performance monitoring tool available from GitHub. It allows for private data collection, distributed tracing via Open Tracing API, Alerting and is fully extendable via 3rd party, community, or custom plugins drafted from scratch. Stagemonitor uses Kibana for dashboarding and visualization.

10. Clinic.js

Clinic.js uses multiple tools to diagnose and remediate performance-related issues in your Node.js application. The doctor diagnoses performance issues and offers guidance when using specialized tools to diagnose your specific problems. Issues such as low CPU usage, obstruction of garbage collection, frequent event delays, or a chaotic number of active actions can indicate many potential problems, and the doctor will guide you to other Clinic.js tools.

Freemium APM Tools

Open-source monitoring tools are great for projects with tight budgets, non-profits, or other open-sourced projects. However, many SaaS offers free or reasonably priced bundles for non-profits, education, and other projects. Also, a self-hosted solution can get expensive really quickly, e.g., a hosted ELK stack from Elastic starts at $95/month. Open Source is rarely free, and many SaaS solutions offer better, more reliable, and reasonably priced Application Performance Monitoring Tools.

1. Better Stack

Better Stack is worth considering alongside the open-source tools on this list for teams that want predictable costs without the infrastructure overhead of self-hosting. Running a production ELK stack or Prometheus with long-term storage is rarely free once you factor in hosting, maintenance, and engineering time. Better Stack's ClickHouse-powered log management delivers sub-second search across billions of log records and collects data from Python, Django, JavaScript, Node.js, PHP, Ruby, .NET, and more via a lightweight client library. Error tracking runs on the Sentry SDK protocol at one-sixth the cost, and the Better Stack Collector instruments your services with zero code changes using eBPF-based auto-instrumentation. See how the Collector instruments your services with zero code changes:

Real user monitoring, distributed tracing, infrastructure monitoring, uptime monitoring, and incident management are all included in one platform — no stitching together separate tools. The AI SRE performs automated root cause analysis across your service map, logs, and traces, integrating with Claude Code and Cursor to help resolve issues faster. The free plan covers 3 GB of logs, 100,000 exceptions, and 10 monitors with no credit card required. See the dashboards and metrics in action:

2. Sentry.io

Sentry is available for free in the Developer pricing model and offers Limited error and Performance monitoring options. Sentry's performance monitoring offers support for various application languages and frameworks and is available both as a SaaS and Self-hosted platform. Sentry offers end-to-end distributed trace monitoring to trace performance issues to their origin.

3. New Relic

New Relic offers a free forever plan with 100GBs/month for free and one user access. New Relic offers a complete monitoring solution covering APM, K8s monitoring, ML Model Monitoring, Log Management, Synthetics, and more. Their Application Performance Monitoring allows you to navigate and visualize your stack, and it offers most of the features you'd expect from such a popular APM monitoring tool.

Conclusion

In this article, we took a closer look at some of the best open-source Application Performance Monitoring tools available in 2026. The importance of a good APM solution is now indisputable, so all it takes is picking the right one. When deciding between an open-source and a SaaS solution, there are a few key aspects to consider:

• Continuity, community, and development. Open-source tools heavily rely on their community. If the last commit was pushed months ago and the repository has only a few active members, you risk future security and compatibility issues.
• Infrastructure costs. Open-source tools such as the Elastic stack can quickly ramp up infrastructure costs, which diminishes your return on investment. A hosted ELK stack starts at $95/month before you account for storage and maintenance — open source is rarely free at scale.
• Integrations with third-party software. Most open-source tools integrate well with third-party tools for tasks such as infrastructure monitoring or incident management. Make sure your stacks are fully compatible before committing.
• The freemium middle ground. For teams that want the flexibility of open source without the operational overhead, tools like Better Stack offer generous free tiers with predictable paid scaling — covering logs, traces, error tracking, uptime monitoring, and incident management in a single subscription rather than a self-managed stack of moving parts.