Dex - Durable Execution(D-EX)

⚠️ Beta: Dex's core features are complete and its core APIs are stable. Minor API refinements may still be introduced before general availability.

Why Durable Execution & Dex

Durable Execution provides programming model that makes a process survive any disruptions.

There are three types of disruptions: * Business disruption * External disruption * Internal disruption

Take a simple refund. A customer asks for a refund. A manager approves it. Then the system calls an API to move the money. But the manager may forget(business discruption). The payment API may be down(external discuprtion). Our own server may restart or has a bug(internal disruption). Then the refund gets stuck, and the business gets hurt. And real refund processes are a hundred times more complex so they have 100 times more disruptions like those.

Dex make every process is a durable execution. Every step is saved, retried, and can wait. If the manager forgets, we send a reminder, or escalate. If the API is down, we keep retrying. If our server restarts, the run picks up right where it stopped.

Dex provides a structural programming model with only a few concepts as durable primitives. You use Dex to write a Flow filled with ordinary code: durable Steps, Attributes, RPCs, and durable conditions using Channels and Timers. Then you run Workers hosting your Flow. The Client calls Dex Server to start and interact with Flow instances. Dex Server dispatches Step and RPC invocation tasks to your Workers.

Underneath, Dex provide local state and control flow such as branches and loops, as well as parallel execution and coordination, waiting for timers or external events, error handling, and remote procedure invocations. The application logic is expressed directly in ordinary code, while the platform reliably restores and resumes the execution after failures and restarts.

Dex is optimized for AI agents, human+AI processes, highly performant & scalable.

It includes in-memory/best-effort streaming, attribute storage sync, and automatic offloading and cleanup of large payloads in blob storage. Dex Connectors Library provides reusable integrations that help you move workflows quickly from prototype to production.

Dex: No Replay

Unlike most durable execution frameworks, Dex takes a fundamentally different approach with its non-replay-based programming model. It eliminates entire classes of footguns—such as replay-induced non-determinism errors and the need for Continue-As-New—by design, rather than forcing developers to work around them.

Dex: Built by a Pioneer in Durable Execution

Dex is created by a founding engineer of Uber Cadence, a core contributor to Temporal, and the original creator of iWF—bringing deep, firsthand experience from multiple generations of durable execution technology.

Forked from iWF by its original creator, Dex builds on a proven foundation with:

• 5+ years of production use, with no known framework-attributable incidents
• Tens of engineering teams relying on the technology
• Millions of workflows running in production

Dex isn't a new programming model being tested for the first time. It's the evolution of a battle-tested architecture, shaped by years of building and operating durable execution systems at scale.

Learn more: What is Durable Execution? · Why Dex?

Dex isn't just designed to make workflows durable. It's designed to make complex, long-lived applications easier to build—and we're open-sourcing real applications to prove it.

How Dex works: Zero Dependencies

Dex is a single binary. There is no database to set up, no message queue to run, and no coordination service to keep alive.

Your application talks to one Dex Server. The server keeps all flow state on its local disk and commits every write to blob storage, so there is no database or queue to run.

If you want your data in your own database for queries and reports, turn on attribute sync and Dex writes it there for you.

Repository modules

How to start

See Quick start on docs.superdurable.io.

AI coding assistants can use the official Dex Skills to build, test, and operate Dex applications through Dex's public programming model. Install either the recommended Dex Plugin or the complete standalone Skills bundle from superdurable/dex-skills, but not both.

The skills/ module contains the Dex Skills source.

You can see examples/ of the repo.

We're also open-sourcing lots of apps built on Dex.

💬 Community

🎉 Join the SuperDurable Dex community on Slack to ask questions, share feedback, and connect with other Dex users and contributors.