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Hi n8n community,

I’m building an Invoice Reminder Automation System that:

  1. Serves an HTML form for users to upload a Weekly Outstanding Invoice Report (Excel/CSV)

  2. Extracts and loads a dynamic customer list from the uploaded file

  3. Lets the user choose 1 of 4 email templates via dropdown:

    • Template 1

    • Template 2

    • Template 3

    • Template 4

  4. Allows multi-customer selection and displays the number of selected customers

  5. Generates an email draft preview for user review, including:

    • A summary of all outstanding invoices

    • A dynamically populated table containing invoice number, due date, and amount

Issues I faced:

  • POST webhook submission was failing

  • GET webhook was returning an empty body

  • Respond to Webhook nodes were not correctly linked

  • Frontend expected JSON, but response was incorrectly set as HTML

  • Unused “Respond to Webhook” node caused execution errors

  • Confusion about whether GET & POST webhooks should share the same path

  • Webhook not receiving binary file correctly due to missing config (Raw Body / Binary field key mismatch)

My questions:

  1. What is the best way to chain Webhook (GET) → Webhook (POST) → Respond to Webhook properly?

  2. How do I pass the uploaded file (report) into Extract From File node correctly?

  3. Can both GET & POST share the same path, or should they be different?

  4. What is the correct response mode if the frontend expects response.json()?

  5. Is it possible to trigger 2 webhooks simultaneously in one flow?

Would appreciate any advice or sample workflows similar to this.

Thanks in advance!

— Justin

2

Might due to CORS problem. Check the webhook trigger option.

  • GET webhook was returning an empty body

You might need to upload your current workflow so we can see what’s wrong during your setting. What kind of the output you setting in webhook and respond to webhook

Can both GET & POST share the same path, or should they be different?

Yes it can. There is a setting in webhook call Allow Multiple HTTP Methods

Screenshot_20260107_174503_EJ5Vsrx3@2x
Screenshot_20260107_174503_EJ5Vsrx3@2x1612×556 30.1 KB

What is the correct response mode if the frontend expects response.json()

Should be json as default

Is it possible to trigger 2 webhooks simultaneously in one flow?

Unlikely. Should be seperate request from your frontend. Or you can put data with-in the POST path. (If you want to show data right after the user submit)