Error Handling

Caught Errors

Use standard try/catch blocks to handle errors and return meaningful responses:

import type { Request, Response } from 'express'

export default (_: Request, res: Response) => {
  try {
    throw new Error('This is an error')
  } catch (error) {
    console.log(error)
    res.status(500).json({
      error: error.message,
    })
  }
}

The console.log(error) call ensures the error appears in your function logs, including the full stack trace. The client receives a structured JSON response.

Unhandled Errors

If an error is thrown without being caught, the function crashes and the client receives a generic error response:

import type { Request, Response } from 'express'

export default (_: Request, _res: Response) => {
  throw new Error('This is an unhandled error')
}

Unhandled errors are still captured in the logs with level ERROR, so you can diagnose them from the logs page.

Caution

Unhandled errors return a generic 500 response to the client with no detail about the failure. Always use try/catch for errors you want to communicate back to the caller.

Best Practices

• Log before responding: Call console.log() or console.error() before sending the response so the error is captured in logs regardless of client behavior.
• Use the invocation ID: Include req.invocationId in log messages to correlate errors with specific requests. See Logging for details.
• Return structured errors: Use a consistent error shape (e.g., { error: string }) so clients can parse failures reliably.
• Set appropriate status codes: Use 400 for bad input, 401/403 for auth failures, and 500 for unexpected server errors.