@flowlinejs/engine

The durable Flowline workflow engine: createEngine interprets a published WorkflowDoc over a pluggable StorageAdapter, exposes an HTTP handler for the editor and run viewer, runs a worker that claims and executes steps, and records every step to a journal and audit trail. Retries, suspension (delay, waitForCallback, sub-flows), webhooks and cron schedules are all built in.

Install

pnpm add @flowlinejs/engine @flowlinejs/core zod@^4
pnpm add @flowlinejs/storage-memory   # or @flowlinejs/storage-postgres

zod 4 is a required peer dependency. Bring your own StorageAdapter: @flowlinejs/storage-memory (for tests and prototypes) is an optional peer, used by runWorkflowInMemory; @flowlinejs/storage-postgres (for production) is a regular dependency, not a peer, and you just install it directly. vitest is an optional peer used only by @flowlinejs/engine/conformance; @flowlinejs/engine/testing never imports vitest, and loads @flowlinejs/storage-memory lazily so testNode alone works without it installed either.

Usage

import { createEngine } from "@flowlinejs/engine";
import { createMemoryStorage } from "@flowlinejs/storage-memory";
import { createRegistry } from "@flowlinejs/core";

const registry = createRegistry([]); // your plugins; core.* builtins are added automatically

export const engine = createEngine({
  registry,
  storage: createMemoryStorage(),
  authorize: async () => ({ tenantId: "acme", userId: "u1" }),
});

// Mount engine.handler (a `(Request) => Promise<Response>`) with any fetch-style server,
// and start a worker to execute claimed runs:
export const worker = engine.startWorker({ concurrency: 4 });

See the root README for the full quick start (nodes, plugin, Postgres storage, HTTP mount, worker, publish, editor) and docs/ for the design spec. @flowlinejs/engine/testing exports runWorkflowInMemory and testNode. @flowlinejs/engine/conformance exports runStorageConformance, a storage conformance suite for testing your own StorageAdapter — its own entry point because it requires vitest.