Custom Response Formatting

By default, Laminar workflows return the output of the last step with a 200 status code (if successful) or 500 (if failed). The lam.response feature gives you more flexibility to return custom HTTP responses with specific status codes and formatting.

This is useful when building API endpoints that need specific HTTP behaviors.

How It Works

When any step returns an object containing lam.response, Laminar will:

1. Exit immediately - Stop executing the workflow at that step

2. Skip remaining steps - No subsequent steps will be executed

3. Return custom response - Use your specified format and status code

Response Structure

• statusCode (required): HTTP status code (200, 201, 400, 404, 500, etc.)

• message (required): Human-readable message

• data (optional): Response data

• error (optional): Error information for error responses

Schema

{
  "lam.response": {
    "statusCode": 200 | 201 | 400 | 404 | ...,
    "message": "message",
    "data": {
      // Your response data here
    },
    "error": {
      "code": "ERROR_CODE",
      "message": "Error description",
      "details": "Additional error details",
      "field_errors": {
        "field1": "Field-specific error message"
      }
    }
  }
}

Examples

Success Response

(data) => {
  return {
    "lam.response": {
      statusCode: 201,
      message: "Dispatch note created successfully",
      data: data.step_4.response,
    },
  };
};

Error Response

(data) => {
  if (!data.input.email) {
    return {
      "lam.response": {
        statusCode: 400,
        message: "Email is required",
        error: {
          code: "VALIDATION_ERROR",
          field: "email",
        },
      },
    };
  }

  // Continue with normal processing
  return { validated: true };
};

Authentication Check

(data) => {
  if (!data.input.apiKey || data.input.apiKey !== "{{config.validApiKey}}") {
    return {
      "lam.response": {
        statusCode: 401,
        message: "Invalid API key",
        error: {
          code: "UNAUTHORIZED",
        },
      },
    };
  }

  // Continue with normal workflow
  return { authorized: true };
};

Use Cases

• API endpoints that need specific HTTP status codes

• Early validation to exit workflows when conditions aren't met

• Authentication checks with proper 401/403 responses

• Error handling with custom error formats