Heroku Fir: Dive into the New Platform Capabilities

For years, Heroku has been empowering developers to deploy and scale their applications with ease. Now, we're thrilled to introduce the general availability of the next generation of the Heroku platform, codenamed Fir, launching later this month April 2025. Built on open source standards and cloud-native technologies, Fir accelerates your development like never before.

A change of this scale is not something that we take lightly. Replatforming decisions can represent a massive shift in user experience and operational processes for a single company; we need to consider the needs of the millions of apps for the thousands of companies running on Heroku. With Fir, we are delivering the foundation for the Next Generation of Heroku which brings the power and breadth of the cloud native ecosystem, without the complexity, and a simple, elegant user experience. Helping our customers do more with minimal disruption.

"The deployment environment was very simple and comfortable. And it was similar to the cedar generation environment."
Team Manager, ICAN Management, Inc

If you're looking for enhanced flexibility, scalability, and robust observability, check out what’s new with this next generation and where Heroku is headed. To explore what Fir means for you and get a firsthand look at the new platform, register for the Fir GA Webinar on April 30th 10:00AM PST / 1:00PM EST, where we’ll walk through the new capabilities and what’s coming next.

See our Demo video to see all the capabilities discussed below in action!

Build Smarter, Not Harder with Cloud Native Buildpacks

A core part of the Heroku experience has long been its ability to take idiomatic code written in nearly any major language and seamlessly turn it into a running application. The Fir generation delivers on that experience using Cloud Native Buildpacks (CNBs) as its standard build system. CNBs analyze your code and automatically build it into secure, efficient, and portable Open Container Initiative (OCI) container images, ready for deployment.

Focus on your code, not container configuration: Instead of grappling with the complexities of writing and maintaining production-ready Dockerfiles, CNBs automate the process of turning your source code into secure, optimized container images. Heroku provides and maintains open source CNBs infused with expertise for your favorite languages, handling dependencies, compilation, and optimization automatically. Leveraging CNBs means deploying to Heroku Fir remains as simple as git push heroku main, freeing you to concentrate on building great features.

Build Once, Run Anywhere: Portability is inherent with CNBs, as they create standard OCI container images. This means you can build your application once on Heroku Fir and confidently run the identical artifact anywhere OCI images are supported: on Heroku Fir, on other OCI-compliant cloud platforms, or locally with Docker. This adherence to open standards gives you deployment flexibility and minimizes vendor lock-in.

Extensible Build Primitive: While Heroku's CNBs cover many scenarios out-of-the-box, the buildpack standard provides a powerful, safe, and composable way to extend the build process. Need support for a niche language or custom build logic? You can create your own CNB or utilize community/third-party buildpacks. These integrate with Heroku's official buildpacks and the standard buildpack lifecycle, offering controlled customization without the pitfalls of managing complex, monolithic Dockerfiles. This standardized extensibility fosters innovation, allowing customers to tailor the platform to their unique needs.

With Cloud Native Buildpacks, Heroku Fir brings containerization within reach for every developer by combining simplicity, security, and portability, all while ensuring compatibility with the OCI ecosystem and tooling.

Deeper Insights with Integrated OpenTelemetry

Observability is paramount for maintaining the health and performance of modern applications. That's why we’re providing OpenTelemetry (OTel) data natively on all Fir-Generation Heroku apps. This widely-adopted framework provides a standardized way to collect and export telemetry data from your applications.

Fir streamlines the process of collecting and exporting telemetry data without extensive configuration. For an immediate, out-of-the-box view, this data automatically populates the familiar Heroku Metrics tab, providing essential insights with zero setup.

When you need to go deeper, Fir's native support for OpenTelemetry allows you to fully utilize its core signals (traces, metrics, and logs) with upstream SDKs in your language.

Comprehensive Telemetry Signals

Comprehensive telemetry signals are fundamental to understanding, optimizing, and maintaining the health of your applications. By leveraging a combination of traces, metrics, and logs, you gain a holistic view of system behavior, enabling faster issue resolution and more informed decision-making.

Traces provide visibility into the execution path of individual requests, allowing you to pinpoint where latency occurs and identify performance bottlenecks across distributed systems. This insight is invaluable for troubleshooting complex issues, across different application architectures. From monoliths to microservices, understanding the full request path via traces is crucial for isolating problems that degrade the user experience.

Metrics offer quantitative measurements of your system’s performance and resource utilization, such as CPU load, memory usage, and request rates. These continuous data streams help you monitor overall system health, detect anomalies, and plan for scalability by forecasting capacity needs.

Logs, on the other hand, capture discrete events that reflect the inner workings of your application. They offer detailed context for debugging errors, auditing user actions, and tracking security events. OpenTelemetry embraces your existing logging solutions by automatically correlating logs with traces using injected context (like trace IDs) for easier troubleshooting across systems, and providing capabilities to standardize and enrich logs from different sources into a more unified format.

When combined, these telemetry signals provide a powerful toolkit for maintaining application reliability, enhancing security, and optimizing performance — ensuring that your systems can scale to meet evolving business demands.

Telemetry Export with Heroku Telemetry Drains

Extending Heroku's hallmark simplicity to modern observability, Fir embraces native OpenTelemetry. Fir's native OpenTelemetry integration makes comprehensive observability straightforward. Crucially, Heroku automatically collects platform and application telemetry (traces, metrics, logs) and seamlessly combines it with any custom instrumentation you add using standard OTel SDKs in your code. This unified stream provides a complete picture of your application's health and performance, all in one place.

Heroku has always prioritized simplicity and ease of use for developers, and the new Heroku Telemetry tools build upon this foundation. Previously, Heroku's log drains allowed developers to effortlessly set up and manage log streams, ensuring that critical application data was easily accessible. Now, you can see from the command below that it’s just as easy to configure app or space level telemetry drains and enable seamless transmission of all this data to your preferred observability backend and tools.

heroku telemetry:add https://telemetry.example.com --app myapp --signals traces,metrics --transport http --headers '{"x-sample-header":"sample-value"}'

Greater Flexibility with Expanded Dyno Options

One of the most significant advancements in the Fir generation is the dramatically expanded range of dyno options. Moving beyond the offerings available in previous generations, Fir provides 18 dyno options across various specifications to match resources exactly to your application’s needs.

This isn't just about having more choices; it's about having the right choices for your applications. You can see the full list of new dyno options in the table below or review the Technical Specifications by Dyno Size.

Precise Resource Allocation: Fir enables precise resource allocation, eliminating over-provisioning or the need to fit applications into mismatched dynos. These new granular options facilitate the fine-tuning of CPU and memory resources for applications, resulting in more efficient and cost-effective deployments.

Greater Optionality: We've listened to your feedback and introduced more intermediate sizes, as well as smaller options like dyno-1c-0.5gb (0.5GB RAM, 1 vCPU) and dyno-2c-1gb (1GB RAM, 2 vCPU). These brand new offerings bring greater optionality to balance your compute, memory, and cost needs.

Optimized for Diverse Workloads: Whether you're running memory-intensive applications, compute-heavy tasks, or general-purpose web services, Fir's diverse dyno families provide optimized configurations to meet your specific performance requirements. By offering this increased granularity, Fir empowers you to optimize your application's performance and costs with unparalleled precision.

Enhanced Platform Data Residency

With this next generation of Heroku, our new architecture allows us to keep all data and services in the same region where our customers are running and storing their data.

All Telemetry data generated by your apps and Heroku’s infrastructure stays within your Fir Space’s region, bolstering Heroku’s data residency capabilities for our customers.

With OpenTelemetry deeply integrated into Fir, you gain valuable insights into your application's performance with built-in support, allowing for more effective monitoring, debugging, and optimization and it all stays local to where your application is running.

Also, now that Cloud Native Buildpacks are the standard build system for our newest platform, that means that all builds are also created within the same space as where the apps and dynos will be run, and therefore will stay in the same region.

With Fir, you have granular control over how your data is stored and where it runs. In addition, you likely boost application performance by using geographical proximity to optimize data access.

Conclusion

The next generation of Heroku is here, designed with you, the developer, in mind. By offering significantly expanded dyno options, embracing the power of Cloud Native Buildpacks, and integrating robust observability with OpenTelemetry, Heroku Fir empowers you to build, deploy, scale, and monitor your applications with greater flexibility, efficiency, and confidence.

While we’re excited the next generation of Heroku is now generally available, we’re just getting started. Fir is the foundation for delivering the most highly requested Heroku features, and it will enable us to ship faster than ever before. We're delighted to share the direction we're heading in, starting with these roadmap items:

• Heroku AppLink for Salesforce
• Enhanced networking features including exposing apps through AWS VPC PrivateLink and AWS Transit Gateway
• Expanded isolation & sandboxing use cases, such as Fir for Multi-Tenancy
• Software supply chain security, including Software Bill of Materials (SBOMs) generation and cryptographically signed build provenance

Want to dive deeper into Fir? Join our team of experts for the Fir GA webinar on April 30th at 10:00AM PST / 1:00PM EST, where we’ll walk through the new platform and give you a sneak peek at what’s ahead.

We’re excited for you to experience the platform and see what you build with it.