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A repository for this article can be found here.‍ When most developers think about request tracing, they picture instrumentation hooks inside familiar libraries. This allows us to track familiar metrics we see in application performance monitoring (APM) tools such as the duration of an HTTP call or how long a database query takes. But what if you could go deeper and instrument your own Ruby code automatically, without sprinkling timing calls everywhere?

Over the past three decades, Ruby has assumed a pivotal role in the modern web stack and become a fixture in the tool kits of countless DevOps and platform teams. Today, it is a driving force in contemporary application development, testing, automation, and CI/CD. For this blog post, we used data from our always-on continuous profiling of more than 3,000 real-world services from hundreds of organizations to track trends in Ruby usage and performance.

Observability has become a core part of running Ruby applications at scale. Knowing how your app performs — from request latency to background job execution — helps catch slowdowns early and improve reliability. This blog walks through some of the most useful APM tools for Ruby in 2025. Each section highlights what the tool does well, where it fits best, and what kind of visibility it brings to your application's performance.

In this guide, we'll harness AppSignal to detect, diagnose, and remove performance bottlenecks and employ proper tracing in a Ruby on Rails application. From setting up tracing to capturing errors and logging, we’ve got you covered. We'll ensure our application runs smoother than ever, even under the heaviest loads! But first, let's quickly touch on how to define tracing and its benefits.

Ruby and Rails are great tools that allow you to create complex web applications quickly. Well, some kinds of complex web applications. While they excel at traditional, monolithic, server-rendered applications, they fail to excel at delivering real-time or distributed services. This is why it's so handy for Rubyists to learn a programming language like Go. Go is designed to write lightweight services that handle lots of inbound connections.

We're excited to announce that AppSignal now offers improved monitoring for long-running streaming Rack responses. Our improved Rack response monitoring means you can gain deeper visibility into the health of your Ruby application's long-running responses, allowing you to catch errors that may arise minutes or even hours after a request's body is served. This new layer of observability results from a valuable contribution from Julik Tarkhanov, Director of Engineering at Cheddar Payments.

One Ruby feature that embodies the principle of “optimizing for programmer happiness” is how the language uses garbage collection (GC) to automatically manage application memory. But as Ruby apps grow, GC itself can become a big consumer of system resources, and this can lead to high CPU usage and performance issues such as increased latency or reduced throughput.

Developed in the mid-1990s, Ruby is a dynamic, open-source programming language. The tool has grown in popularity from its initial release, having been used in modern systems covering a variety of corporate and academic use cases. Ruby gained further traction after the release of Ruby on Rails, a powerful web application framework written in pure Ruby.