Announcing Akka 3

I’m incredibly excited to announce Akka 3!

Akka 3 is generally available to the public and is already running several large scale systems. You can start building at akka.io. 

I started Akka 15 years ago with the desire to simplify how developers create applications that scale across multiple cores. Akka has grown into one of the world’s most popular open source projects, downloaded over 1 billion times and used by millions of developers.

Akka has gone through multiple generations to design a modern set of APIs for building distributed systems that could be elastic, agile, and resilient. It has grown to include abstractions for every layer of an application from actors to networking, persistence, integration, and replication.

We have worked with 1000s of customers helping them to adopt Akka to address their most challenging needs. We heard—and learned—three important lessons:

1. Akka just works.
2. Akka is complex.
3. Akka doesn’t operate my app.

Akka 3 is the next generation of Akka—a platform for building and running responsive apps. We are delivering an Akka that is easy to learn, operates your apps, and still “just works.” 

While we have introduced new ways to build and run Akka apps, those are additive and have no impact on your existing applications.

The Akka libraries that you have used over the last 15 years are also included in the new Akka, will always be a part of Akka, and will indefinitely have new feature investments. The Akka libraries are foundational to our company, our business, and our products.

We started thinking about Akka 3 more than 8 years ago and it’s been in development since 2018. Akka 3 is the genesis and distillation of many Lightbend projects including Lagom, Play Framework, Cloudstate, Cloudflow, Akka Streams, and Kalix. 

Akka 3 has been privately incubated, generating more than $1M of recurring revenues, and is running multiple large scale systems with customers who are not quite ready to be publicly identified:

1. Global SaaS vendor with 2M users porting a non-scaling .NET app.
2. International bank transforming 4-week manual processes into hours-long workflows.
3. Online retailer that required writable 1M+ IOPS with <20ms latency.

While still including all of the OSS libraries that have been the backbone of distributed systems development for the last 15 years, Akka has expanded to become a platform for building and operating applications:

1. SDK: Akka now has an SDK which includes high-level components and a great local development environment including local developer sandboxes, local console, and event debugger. Developers build and iterate with a tight feedback loop even if they are building multiple networked services. The new SDK ships with composable components—endpoints, entities, views, streaming consumers, workflows, and timers—that makes it very easy to build responsive, elastic, and resilient cloud applications. The learning curve with Akka is now hours vs. weeks with Akka libraries.
2. Environments: You can run Akka applications today in two different environments: Serverless (sign up, register credit card, and scale—pay-as-you-grow with shared or dedicated resources) and Bring Your Own Cloud (BYOC, you bring the cloud and we bring the Akka control plane, clear cut cost profile and managed infrastructure services). And, early in 2025, a third option: Self-Hosted (allowing you to run Akka apps wherever you want, on-premises, in your private cloud, or a hybrid cloud).
3. Operations: We have focused a lot on making it easier to operate Akka in the cloud, which includes adding more flexibility to how an Akka application is deployed and replicated supporting Single-region/Pinned; Multi-region/Read-replicated; and Multi-region/Write-replicated topologies. We have ensured that it’s easy to perform environment migrations, upgrades, and managing versioning with zero downtime.

Over the last 3 years, we have been working on new innovations that are surfaced within Akka 3:

1. The first application runtime that has Multi-Master Replication. This means that one single entity/service can have instances running in multiple locations (different regions or clouds), serving both reads and writes. It’s implemented using replicated event logging and CRDTs, with a protocol running over reliable gRPC supporting guaranteed delivery of the events.
2. The first PaaS that migrates apps across hyperscalers. Building on our Multi-Master Replication we have implemented means to make it easy for operations to stretch the application across multiple clouds, and migrate an app from one cloud to another—all without any downtime or disruption. These features also mean that operations can do upgrades of the application, individual services, or data model without any disruption.
3. The first vendor to indemnify your app’s resilience. With the launch of Akka 3 we are also guaranteeing your application’s resilience. It’s part of the SLA you get, which means that it’s on us to worry about. We can confidently do this: Akka apps have never had a Sev1 due to Akka. It’s rock solid and hardened.

Akka 3 was built with the OSS libraries that we’ve been engineering for the last 15 years. And as a result, Akka 3 is also a responsive application that lets you build and run your own responsive applications. Akka 3 is blazing fast, and our latest benchmarks prove it.

We are so excited to see what the world will build and run with Akka.

Questions? Contact me directly: jonas@akka.io. You may also enjoy reading the companion blog from Tyler Jewell, our CEO.

Discover what the next generation of Akka can do for you—join our webinar on November 20.
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