A TypeScript library that runs durable, multi-stage workflows in your own Postgres. No server to deploy, no vendor: install it, hand it a Prisma client, and run it from a Node process, a serverless function or a cron trigger. Workflow state lives in tables beside your application's tables.

Built for pipelines whose expensive steps are model calls, so what it takes seriously is suspending across hours, per-call cost, and provider batch endpoints:

• The kernel can run inside your transaction. It is a pure command dispatcher with no connection of its own, so building its persistence port over a Prisma transaction client puts the whole tick on your session — where a SET LOCAL for your tenant and your row-level security policies apply.
• Provider batch APIs are durable steps. ctx.step.ai.map submits to OpenAI Batch, Anthropic Message Batches, Google/Vertex batch or OpenRouter :batch, suspends and releases its lease, and resumes from the step ledger — adopting an in-flight batch rather than paying for a second one after a crash.
• Cost is a column, not a trace. Tokens and cost land on WorkflowRun.totalCost in the same transaction as the stage that spent them, priced from the endpoint actually used (batch prices for a batch call, not a flat 50% off), so the next stage can gate on spend.
• Schema problems fail before submit. A schema no provider dialect can express raises UnportableSchemaError naming the path and the keyword, rather than a provider 400 — or, on Anthropic, a batch that reports its validation errors a day later.

It is alpha, TypeScript-only, and the pipeline shape is linear execution groups rather than an arbitrary DAG. The introduction says what it deliberately does not do, and where another project is the better choice.

• @bratsos/workflow-engine - Core library (npm)
• @bratsos/workflow-engine-host-node - Node.js host with process loops, signal handling, and continuous job polling
• @bratsos/workflow-engine-host-serverless - Serverless host for Cloudflare Workers, AWS Lambda, Vercel Edge, etc.
• @bratsos/workflow-engine-host-remote - Credential-free remote activity workers -- run a stage on a separate machine that never sees your database or provider credentials
• @bratsos/workflow-engine-console - Optional embeddable operational console: a (Request) => Promise<Response> handler plus a prebuilt UI you mount in your own app, reading through your own Prisma client or transaction (runs, step ledger, signals, redrive, dead letters, costs)

The engine follows a kernel + host pattern:

• Core library provides the command kernel, stage/workflow definitions, durable steps (ctx.step.*, backed by a step ledger), and persistence adapters.
• Host packages wrap the kernel with environment-specific process management (polling loops, signal handling, request lifecycles, job lease heartbeats that abort a cancelled stage).
• The kernel is a pure command dispatcher -- no timers, no signals, no global state -- making it portable across any runtime.
• The console is optional and nothing in the engine depends on it.

pnpm install
pnpm build
pnpm test

See the package README for full API documentation and usage examples. The agent skill under packages/workflow-engine/skills/workflow-engine/ carries the reference (durable steps, definition versioning, redrive, large payloads, the console) and the migrate-0.13-to-1.0.md upgrade guide.

MIT