workflow/docs/errors/start-invalid-workflow-function.mdx

Workflow DevKit - Build durable, resilient, and observable workflows

---
title: start-invalid-workflow-function
description: Ensure you pass a valid workflow function to start() with proper configuration.
type: troubleshooting
summary: Resolve the start-invalid-workflow-function error by passing a properly configured workflow function.
prerequisites:
  - /docs/foundations/starting-workflows
related:
  - /docs/api-reference/workflow-api/start
---

This error occurs when you try to call `start()` with a function that is not a valid workflow function or when the Workflow DevKit is not configured correctly.

## Error Message

```
'start' received an invalid workflow function. Ensure the Workflow DevKit
is configured correctly and the function includes a 'use workflow' directive.
```

## Why This Happens

The `start()` function expects a workflow function that has been properly processed by Workflow DevKit's build system. During the build process, workflow functions are transformed and marked with special metadata that `start()` uses to identify and execute them.

This error typically happens when:

* The function is missing the `"use workflow"` directive
* The workflow isn't being built/transformed correctly
* The function isn't exported from the workflow file
* The wrong function is being imported

## Common Causes

### Missing `"use workflow"` Directive

```typescript lineNumbers title="workflows/order.ts"
// Error - missing directive
export async function processOrder(orderId: string) { // [!code highlight]
  // workflow logic
  return { status: "completed" };
}
```

**Solution:** Add the `"use workflow"` directive.

```typescript lineNumbers title="workflows/order.ts"
// Fixed - includes directive
export async function processOrder(orderId: string) {
  "use workflow"; // [!code highlight]

  // workflow logic
  return { status: "completed" };
}
```

### Incorrect Import

```typescript lineNumbers title="app/api/route.ts"
import { start } from "workflow/api";
// Error - importing step function instead of workflow
import { processStep } from "@/workflows/order"; // [!code highlight]

export async function POST(request: Request) {
  await start(processStep, ["order-123"]); // Error! // [!code highlight]
  return Response.json({ started: true });
}
```

**Solution:** Import the correct workflow function.

```typescript lineNumbers title="app/api/route.ts"
import { start } from "workflow/api";
// Fixed - import workflow function
import { processOrder } from "@/workflows/order"; // [!code highlight]

export async function POST(request: Request) {
  await start(processOrder, ["order-123"]); // [!code highlight]
  return Response.json({ started: true });
}
```

### Next.js Configuration Missing

```typescript lineNumbers title="next.config.ts"
// Error - missing withWorkflow wrapper
import type { NextConfig } from "next";

const nextConfig: NextConfig = {
  // your config
};

export default nextConfig;
```

**Solution:** Wrap with `withWorkflow()`.

```typescript lineNumbers title="next.config.ts"
// Fixed - includes withWorkflow
import { withWorkflow } from "workflow/next"; // [!code highlight}
import type { NextConfig } from "next";

const nextConfig: NextConfig = {
  // your config
};

export default withWorkflow(nextConfig); // [!code highlight]
```