createEngine(config)

Creates an engine that executes workflows against a storage backend.

import { createEngine } from 'reflow-ts'

const engine = createEngine({
  storage,
  workflows: [orderWorkflow, emailWorkflow],
})

Parameter	Type	Default	Description
storage	StorageAdapter	required	Backend for runs and step results
workflows	Workflow[]	required	Workflows to register
hooks	EngineHooks	—	Lifecycle hooks (may be sync or async)
concurrency	number	1	Runs processed in parallel per tick
runLeaseDurationMs	number	30000	How long a claimed run stays running before another engine may reclaim it
heartbeatIntervalMs	number	lease / 3	How often the active worker renews its lease

Returns an Engine. Registering the same workflow name twice throws DuplicateWorkflowError; invalid numeric config throws ConfigError (concurrency must be a positive integer, heartbeatIntervalMs must be smaller than runLeaseDurationMs).

EngineHooks

All hooks are optional and receive an EngineEvent-shaped payload. They may be synchronous or async (awaited). A throwing or rejecting hook never affects engine state.

Hook	Payload
onRunStart	{ runId, workflow }
onStepStart	{ runId, workflow, stepName }
onStepComplete	{ runId, workflow, stepName, output, attempts }
onRunComplete	{ runId, workflow, output }
onRunFailed	{ runId, workflow, stepName, error }
onError	(error: Error) — background failures (scheduled enqueues, poll cycles)

See Hooks for behavior and Events & Streams for the event shapes.