Open Source Workflow Engine

Cadence is an open-source workflow engine for building fault-tolerant, stateful distributed applications. It is released under the Apache 2.0 license, hosted by the Linux Foundation, and actively maintained by contributors from Uber and the broader open-source community.

The full source — server, Go client, Java client, web UI, and Helm charts — is on GitHub. You can run Cadence on your laptop in under five minutes with a single SQLite binary, or deploy it to Kubernetes with a Helm chart. No license key, no usage limits, no vendor dependency.

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Why open source matters for a workflow engine

A workflow engine sits at the center of your most critical business processes. Open source changes the risk profile of that dependency significantly.

Concern	Proprietary / hosted-only engine	Cadence (open source)
Vendor lock-in	Workflows are tied to a provider's API and pricing	Run anywhere; migrate to your own cluster at any time
Auditability	Black box — you cannot inspect how state is stored or replayed	Full source available; persistence schema is documented and versioned
Data residency	Payloads stored on provider infrastructure	Your workflows stay in your VPC, your region, your storage tier
Customization	Blocked by the provider's feature roadmap	Fork, extend, or contribute upstream
Cost at scale	Per-workflow or per-execution pricing adds up	Operational cost only — no per-execution fee
Community support	Vendor-controlled SLAs	Stack Overflow, CNCF Slack, GitHub Issues, community contributors

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Deployment options

Cadence supports four deployment modes. Start with the simplest one that fits your stage.

Mode	Backend	When to use
SQLite	Embedded SQLite	Local development, demos, CI — no Docker required
Docker Compose	Cassandra or MySQL in containers	Team dev environment, local integration tests
Kubernetes (Helm)	Cassandra, MySQL, or Postgres	Staging and production
Managed (Uber)	Uber-operated multi-tenant cluster	Uber internal teams

Local quickstart

SQLite mode requires no Docker and no external database. It is the fastest path from a fresh clone to a running Cadence server.

SQLite (no Docker)

git clone https://github.com/cadence-workflow/cadence.git
cd cadence
make bins
make install-schema-sqlite
./cadence-server --zone sqlite start

Open http://localhost:8088 for the Cadence Web UI.

Docker Compose

git clone https://github.com/cadence-workflow/cadence.git
cd cadence/docker

# Starts Cadence + Cassandra
docker-compose up

# Or use the MySQL variant
docker-compose -f docker-compose-mysql.yml up

Pre-built Docker images are available on Docker Hub

The server image ubercadence/server is updated with every release. See Docker Hub.

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Client SDKs

Language	Status	Repository
Go	Official	cadence-workflow/cadence-go-client
Java	Official	cadence-workflow/cadence-java-client
Python	Community	—
Ruby	Community	coinbase/cadence-ruby
.NET	In development	—

You can also use iWF as a DSL framework that runs on top of Cadence if you prefer a state-machine abstraction over raw workflow code.

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Hello World

The smallest possible Cadence program registers a workflow, registers an activity, starts a worker, and runs the workflow from a client.

Go

func HelloWorkflow(ctx workflow.Context, name string) (string, error) {
    ao := workflow.ActivityOptions{ScheduleToCloseTimeout: 10 * time.Second}
    ctx = workflow.WithActivityOptions(ctx, ao)

    var result string
    err := workflow.ExecuteActivity(ctx, HelloActivity, name).Get(ctx, &result)
    return result, err
}

func HelloActivity(ctx context.Context, name string) (string, error) {
    return "Hello, " + name + "!", nil
}

Java

public interface HelloWorkflow {
    @WorkflowMethod
    String sayHello(String name);
}

public class HelloWorkflowImpl implements HelloWorkflow {
    private final HelloActivities activities =
        Workflow.newActivityStub(HelloActivities.class);

    @Override
    public String sayHello(String name) {
        return activities.greet(name);
    }
}

Full step-by-step guides: Golang Hello World · Java Hello World

Register workflows and activities on every worker

Every worker that polls a task list must register all workflows and activities that may run on that task list. A worker that receives a task for an unregistered type will abandon the task and block the workflow until a correctly registered worker picks it up.

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Persistence backends

Backend	Production use	Notes
Cassandra	Yes	Recommended for high-throughput, multi-region deployments
MySQL 8	Yes	Simpler ops for teams already running MySQL
Postgres	Yes	Fully supported; schema in schema/postgres/
SQLite	Local dev only	Embedded, zero-config; not for production

Schema migrations are managed by the cadence-sql-tool CLI bundled with the server binary. See CONTRIBUTING.md for setup instructions.

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Community

Channel	Link
CNCF Slack (#cadence-workflow)	Join
Stack Overflow	cadence-workflow tag
GitHub Issues	cadence-workflow/cadence/issues
GitHub Discussions	cadence-workflow/cadence/discussions
Reddit	r/cadenceworkflow
OSS Community Survey	2025 Survey

Contributions to the server, SDKs, docs, and samples are welcome. See CONTRIBUTING.md for the development setup, coding standards, and PR process.

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References

• Workflow Engine and Orchestration — how Cadence works as a workflow engine
• Get Started — server installation, HelloWorld samples, Video Tutorials
• Deployment Topology — Frontend, Matching, History, Worker services
• GitHub org: github.com/cadence-workflow
• Docker Hub: ubercadence/server
• Helm charts: cadence-workflow/cadence-charts