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Interface: WorkerOptions


Options to configure the Worker



Optional activities: ActivityInterface

Mapping of activity name to implementation.


Optional buildId: string

A string that should be unique to the exact worker code/binary being executed.

This is used to populate the binaryChecksum attribute in history events originated from this Worker.

default @temporalio/worker package name and version + checksum of workflow bundle's code


Optional bundlerOptions: Object

Type declaration

ignoreModules?string[]List of modules to be excluded from the Workflows bundle. Use this option when your Workflow code references an import that cannot be used in isolation, e.g. a Node.js built-in module. Modules listed here MUST not be used at runtime. > NOTE: This is an advanced option that should be used with care.


Optional connection: NativeConnection

A connected NativeConnection instance.

If not provided, the worker will default to connect insecurely to localhost:7233.


Optional dataConverter: DataConverter

Provide a custom DataConverter.


Optional debugMode: boolean

If true Worker runs Workflows in the same thread allowing debugger to attach to Workflow instances.

Workflow execution time will not be limited by the Worker in debugMode.

default false


Optional defaultHeartbeatThrottleInterval: string | number

Default interval for throttling activity heartbeats in case ActivityOptions.heartbeat_timeout is unset. When the timeout is set in the ActivityOptions, throttling is set to heartbeat_timeout * 0.8.

format ms formatted string

default 30 seconds


Optional enableNonLocalActivities: boolean

Whether or not to poll on the Activity task queue.

If disabled and activities are registered on the Worker, it will run only local Activities.

default true


Optional enableSDKTracing: boolean

Enable opentelemetry tracing of SDK internals like polling, processing and completing tasks.

Useful for debugging issues with the SDK itself.

For completeness the Rust Core also generates opentelemetry spans which connect to the Worker's spans. Configure {@link CoreOptions.telemetryOptions} to enable tracing in Core.

default false


Optional identity: string

A human-readable string that can identify your worker

default ${}@${os.hostname()}


Optional interceptors: WorkerInterceptors

A mapping of interceptor type to a list of factories or module paths


Optional maxActivitiesPerSecond: number

Limits the number of activities per second that this worker will process. The worker will not poll for new activities if by doing so it might receive and execute an activity which would cause it to exceed this limit. Must be a positive floating point number.

If unset, no rate limiting will be applied to Worker's activities.


Optional maxCachedWorkflows: number

The number of Workflow isolates to keep in cached in memory

Cached Workflows continue execution from their last stopping point. If the Worker is asked to run an uncached Workflow, it will need to replay the entire Workflow history. Use as a dial for trading memory for CPU time.

You should be able to fit about 500 Workflows per GB of memory dependening on your Workflow bundle size. For the SDK test Workflows, we managed to fit 750 Workflows per GB.

default max(os.totalmem() / 1GiB - 1, 1) * 200


Optional maxConcurrentActivityTaskExecutions: number

Maximum number of Activity tasks to execute concurrently. Adjust this to improve Worker resource consumption.

default 100


Optional maxConcurrentLocalActivityExecutions: number

Maximum number of Activity tasks to execute concurrently. Adjust this to improve Worker resource consumption.

default 100


Optional maxConcurrentWorkflowTaskExecutions: number

Maximum number of Workflow tasks to execute concurrently. Adjust this to improve Worker resource consumption.

default 100


Optional maxHeartbeatThrottleInterval: string | number

Longest interval for throttling activity heartbeats

format ms formatted string

default 60 seconds


Optional maxTaskQueueActivitiesPerSecond: number

Sets the maximum number of activities per second the task queue will dispatch, controlled server-side. Note that this only takes effect upon an activity poll request. If multiple workers on the same queue have different values set, they will thrash with the last poller winning.

If unset, no rate limiting will be applied to the task queue.


Optional namespace: string

The namespace this worker will connect to

default "default"


Optional shutdownGraceTime: string | number

Time to wait for pending tasks to drain after shutdown was requested.

format ms formatted string or number of milliseconds

default 5s


Optional sinks: InjectedSinks<any>


Optional stickyQueueScheduleToStartTimeout: string

How long a workflow task is allowed to sit on the sticky queue before it is timed out and moved to the non-sticky queue where it may be picked up by any worker.

format ms formatted string

default 10s


taskQueue: string

The task queue the worker will pull from


Optional workflowBundle: WorkflowBundleOption

Use a pre-built bundle for Workflow code. Use bundleWorkflowCode to genrate a bundle.

This is the recommended way to deploy Workers to production.

See for more information.


Optional workflowsPath: string

Path to look up workflows in, any function exported in this path will be registered as a Workflows in this Worker.

If this option is provided to Worker.create, Webpack compliation will be triggered.

This option is typically used for local development, for production it's preferred to pre-build the Workflow bundle and pass that to Worker.create via the workflowBundle option.

See for more information.