Durable Workflow Python SDK

Build durable Python workflows and activities against Durable Workflow Cloud or a self-hosted Server. The SDK uses the same language-neutral runtime protocol as the first-party PHP and Rust SDKs.

pip install durable-workflow

Python 3.10 or newer is required.

import asyncio
from uuid import uuid4

from durable_workflow import Client, Worker, workflow, activity

@activity.defn(name="greet")
def greet(name: str) -> str:
    return f"hello, {name}"

@workflow.defn(name="greeter")
class GreeterWorkflow:
    def run(self, ctx, name):
        result = yield ctx.schedule_activity("greet", [name])
        return result

async def main():
    workflow_id = f"greet-{uuid4().hex}"
    async with Client(
        "http://server:8080",
        token="dev-token-123",
        namespace="default",
    ) as client:
        worker = Worker(
            client,
            task_queue="python-workers",
            workflows=[GreeterWorkflow],
            activities=[greet],
        )
        handle = await client.start_workflow(
            workflow_type="greeter",
            workflow_id=workflow_id,
            task_queue="python-workers",
            input=["world"],
        )
        await worker.run_until(workflow_id=workflow_id, timeout=30.0)
        result = await client.get_result(handle)
        print(result)  # "hello, world"

if __name__ == "__main__":
    asyncio.run(main())

Pass the Server origin to Client without a trailing /api. For Cloud, pass the complete namespace runtime URL exactly as provisioned. Cloud client and worker processes use separate runtime credentials:

client = Client(
    runtime_url,
    control_token=client_token,
    worker_token=worker_token,
    namespace=namespace,
)

Keep the client token in application processes and the worker token in worker processes when deploying them separately.

• Workflows, activities, child workflows, timers, and continue-as-new
• Signals, queries, validated updates, schedules, and message streams
• Activity retries, timeouts, cancellation, and heartbeats
• Deterministic parallel work, side effects, version markers, and sagas
• Replay verification and an in-process workflow test environment
• Avro payloads, external payload storage, metrics, and interceptors

See the capability matrix for the complete cross-SDK contract.

• Python SDK portal and API reference
• Python SDK guide
• Complete SDK reference
• Runnable examples
• Symmetric SDK playground

Use Durable Workflow Cloud for a managed namespace, or run the published durableworkflow/server image yourself. Workflow and activity type names, task queues, and payloads are portable between both runtime choices.

Stable 2.x SDK releases follow semantic versioning and negotiate runtime capabilities with Server at startup. Use stable 2.x SDK and Server channels for new applications. The compatibility guide documents protocol and upgrade guarantees.

pip install -e '.[dev]'
ruff check src/ tests/
mypy src/durable_workflow/
pytest tests/ -m "not integration"

Integration tests use Docker:

docker compose -f docker-compose.test.yml up -d --build --wait
pytest tests/integration/ -v
docker compose -f docker-compose.test.yml down -v

MIT