vs Polly and Failsafe vs Polly and Failsafe

Explore the shift from traditional resilience libraries to's innovative approach for managing third-party API consumption. This post delves into Lunar's unique features, including easy integration, plugin chaining, and its open-source commitment, offering a streamlined solution for modern software development challenges.

Sean Keegan, Head of DevRel

Sean Keegan, Head of DevRel

February 16, 2024



In today's tech ecosystem, where seamless operation is paramount, the mastery of third-party API consumption has emerged as a critical skill set. This evolution reflects the increasing complexity and scale of applications that rely heavily on external services. Historically, open-source software (OSS) resilience libraries like Polly and Failsafe have risen to the challenge, offering developers tools to ensure their systems can adeptly manage egress traffic and recover from failures with grace. These libraries have become vital in crafting strategies that bolster fault tolerance and enhance application reliability.

However, as the digital environment continues to advance, there's a growing need for solutions that not only tackle the management of third-party API usage effectively but also simplify the process. Enter, an open-source project (Lunar on GitHub) that goes beyond traditional resilience libraries. introduces a new paradigm for the simplified management of third-party API usage, offering a solution that's not just about keeping up but setting new standards in egress control. With an emphasis on ease of use and integration, is crafted to tackle the unique challenges of API consumption at scale, making resilience more accessible and effective for developers.

Join us as we explore how is reshaping the landscape of third-party API management and contributing to the open-source community, offering a glimpse into the future of software development resilience.

The Challenge with Traditional Resilience Libraries

For years, resilience libraries such as Polly and Failsafe have been at the forefront of enabling software applications to withstand the unpredictable nature of digital environments. They've provided the frameworks necessary for implementing retries, circuit breakers, and fallback mechanisms, essential components of any resilience strategy. However, as indispensable as these tools have become, they bring with them a set of challenges that can stymie even the most experienced developers.

The complexity of configuring these libraries to suit specific application needs can be daunting. A deep dive into the documentation is often required to merely scratch the surface of their capabilities, turning what should be a straightforward task into a Herculean effort. Additionally, the rigidity of these frameworks means that once policies are set, making adjustments in response to dynamic conditions—a requirement in today's fast-paced digital ecosystems—can be cumbersome and time-consuming.

Perhaps the most significant hurdle is the steep learning curve associated with mastering these libraries. For new developers or those working in small teams, the time investment needed to effectively implement and manage these resilience strategies can divert resources away from core development tasks, impacting productivity and innovation.

As developers grapple with these challenges, the quest for a more accessible, flexible, and user-friendly approach to resilience strategy management becomes increasingly urgent. This necessity sets the stage for the introduction of, a tool designed to democratize resilience in software development by simplifying the complexities that have long been accepted as par for the course.

Simplifying Resilience with

In today’s digital ecosystem, where resilience is critical, stands out by simplifying the complexity that usually comes with building resilient systems. Lunar’s platform is built on the principle that ensuring digital resilience should be straightforward and accessible, providing developers with an array of plugins and features designed for ease of use and effectiveness.

  • Easy Implementation: sets itself apart with a remarkably simple integration process. It allows for seamless adoption into existing tech stacks with a single line of code. Installation is simple as installing an SDK and pulling a Docker image. This approach eliminates the need for code changes, making Lunar compatible with Java, TypeScript, and Python environments. It's a stark contrast to the extensive coding and configuration work often required by traditional resilience libraries.
  • Effortless Customization: Central to Lunar’s design is the ability to easily customize resilience strategies to fit the specific needs of any application. Thanks to YAML configurations, making adjustments to resilience policies is not only straightforward but can be done swiftly, allowing applications to adapt to new challenges without delay.
  • A Clear Advantage: Unlike the more traditional tools like Polly and Failsafe, which may require a deep understanding of their frameworks and significant time investment to implement resilience strategies effectively, simplifies the journey. The platform’s user-friendly interface and minimal setup requirements offer a clear advantage, ensuring developers can enhance their applications' resilience without getting bogged down in the minutiae.’s Standout Features and Seamless Integration revolutionizes the way developers approach software resilience by offering an innovative suite of plugins that are not only powerful but also exceptionally user-friendly. These plugins, designed for both diagnosis/export and remediation, provide a level of flexibility and ease of customization that sets Lunar apart from traditional resilience libraries

Overview of Lunar Plugins

At its core, Lunar’s plugin system allows for straightforward integration into any application, enabling developers to implement complex resilience strategies with minimal effort. These plugins are categorized into two main types: Diagnose & Export Plugins for monitoring and analysis, and Remedy Plugins for actively managing and mitigating issues.

Ease of Customization

What truly distinguishes is its commitment to simplicity and efficiency. Customizing plugin behavior to control your API consumption is as easy as modifying a YAML configuration file, which means developers can adapt and fine-tune their resilience strategies without diving deep into code. This approach not only saves time but also empowers developers to make changes on the fly, responding dynamically to the evolving needs of their applications.

Below is a sample of how straightforward a YAML file looks for controlling response-based throttling:

A sample YAML file for the Response Based Throttling Plugin

For a more thorough walkthrough, watch one of our engineers explore some simple ways to customize remedy and diagnosis policies to solve API consumption issues.

Highlighted Plugins and Their Value

  • Retry Plugin: Automates the retry process for failed API calls, significantly reducing the manual effort involved in managing transient errors. Compared to other solutions, Lunar's retry logic is both easier to implement and more flexible, allowing for detailed configuration based on specific failure conditions.
  • Strategy-Based Throttling: Offers a proactive means to manage API request rates, preventing overload before it happens. Unlike traditional throttling mechanisms that often require custom coding, Lunar’s strategy-based approach is configurable directly through YAML, making it accessible and adaptable to any scenario.
  • Response-Based Throttling: Enhances the adaptability of your applications by adjusting request rates in real-time based on API response data. This level of dynamic response is a game-changer, offering a smarter way to maintain stability and performance under varying load conditions.

The Power of Plugin Chaining

Individual plugins on their own are nice. But the real power behind is its Remedy Chaining capability. This allows developers to combine multiple plugins—like retry mechanisms with throttling strategies—into a cohesive, multi-layered resilience strategy. Chaining plugins amplifies their individual strengths, providing a comprehensive solution that is greater than the sum of its parts. This unique feature enables applications to handle a wide array of failure scenarios more gracefully and efficiently than ever before.

A visual representation of the Remedy Chaining architecture

Remedy Stats for Informed Decision-Making

Complementing its plugin suite, Lunar also offers Remedy Stats, a feature that provides valuable insights into the performance and effectiveness of your resilience strategies. This analytics capability ensures that decisions around adjustments and optimizations are data-driven, offering a clear view into how changes impact application behavior and performance. in Practice's efficacy extends beyond its feature set, demonstrated through tangible successes and enthusiastic endorsements from the developer community. A prime example is HiredScore's implementation of to address their recurring 429 errors, showcasing's immediate impact on operational efficiency.

HiredScore's Journey with

HiredScore, grappling with persistent 429 "Too Many Requests" errors, turned to for a solution. The outcome? A remarkable reduction in back-off errors by 50% and an achievement of 100% successful API calls. This success story is a testament to's capability to tackle real-world challenges head-on, with minimal overhead. " helped us solve an acute recurring 429 problem in production. What I loved about it was the easy installation and lightweight solution," reflects a HiredScore executive, highlighting the simplicity and effectiveness of integrating into their systems.

Voices from the Developer Community

The accolades for don't stop there. The developer community has voiced strong support for's approach to API resilience:

  • "Lunar is changing the game for consumed APIs in production. I’m happy to see a robust but surprisingly simple infrastructure solution like Lunar, giving developers more autonomy to fix and optimize consumed APIs on the fly."

  • Echoing this sentiment, another developer shares, "I've been waiting for a solution like this, that's focused on API consumers, for years! Lunar ensures business continuity on another level - downtime, security, costs, and even policy enforcement are more easily managed in a unified way."

These testimonials underscore Lunar’s transformative impact on simplifying and optimizing API resilience strategies, providing a beacon for developers navigating the complexities of modern software ecosystems.

Resilience in Community’s straightforward, plug-and-play methodology addresses the varied and evolving needs of development teams, offering a practical solution to the challenges of API maintenance without the burden of high costs or complex integrations. With a foundation rooted in real-world applications and supported by positive community feedback, showcases its dedication to enhancing digital resilience through a user-centric platform. 

Recognizing the importance of accessibility and community collaboration, Lunar also provides a free, open-source version of its product, inviting developers to explore its capabilities and contribute to the ongoing evolution of open-source solutions. We’re committed to the open-source community and aim to be a pioneer in fostering a more efficient and reliable future for software development.


From the foundational resilience for third party APIs provided by tools like Polly and Failsafe, emerges, offering a streamlined, user-friendly platform that transforms the approach to digital resilience. This narrative isn't just about technology evolving; it's about making resilience strategies more accessible, manageable, and effective for developers everywhere. has not only simplified the complexity of implementing and managing these strategies but also empowered developers with the autonomy to adapt and optimize on the fly, ensuring applications remain robust in the face of adversity.

Ready to enhance your resilience strategies with minimal hassle? Explore today and experience firsthand the ease of updating policies to meet your evolving needs.

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