Webhook payload not being processed correctly

The raw webhook payload is likely getting mangled because Zapier treats it as text by default, converting binary to escaped strings or UTF-8. Switch to a Code by Zapier step (JavaScript or Python) to handle it as base64 or bytes properly, then pass the clean buffer to Google Drive upload. That usually fixes corrupted PNGs from raw hooks. If still stuck, share your exact steps for a closer look.

This is a pretty common gotcha with Catch Raw Hooks in Zapier.

What you’re seeing usually happens because Zapier is treating the incoming payload as text (UTF-8 / ASCII) instead of true binary, even though the header says image/png. Once that happens, the file is already corrupted before it ever reaches Google Drive.

A few things that usually fix this:

• Make sure the webhook sender is base64-encoding the file
• In Zapier, pass the file using a File object (not raw body text)
• If base64 is used, add a Utilities → Line-itemizer / Utilities → Utilities (Decode Base64) step before uploading
• Upload to Google Drive using the File (Exists but not shown) field, not a mapped text field

Zapier doesn’t reliably handle raw binary streams end-to-end. Encoding → decoding is almost always required, even if the content-type looks correct.

If you want, I’m happy to sanity-check the webhook payload structure or suggest a cleaner handoff pattern.

Hi ​@clivado 

Help us have more info by answering these questions:

1. What app is sending the webhook? (name)
2. What app event is causing the webhook to be sent? (e.g. new record, updated record, etc.)

​@Krzysztof and​ @AKINLOLU ABDULMUQEET thanks for your responses.

• I don’t have any control over the content other than the file type (e.g. PNG, PDF etc.) - I can’t send as Base64
• There is no File object field available from the Catch Raw Hook step, just the raw body along with all the HTTP headers 
• I am using the File field to upload to GDrive. It creates the file, but is corrupted.

​@Troy Tessalone 

• The app is Omni, a business intelligence platform
• The event is a dashboard delivery, e.g. send the sales dashboard at 9am each day to a webhook

​@clivado 

You may want to try exploring other Omni delivery destination options:

https://docs.omni.co/share/deliveries

• Email
  • Email by Zapier: https://zapier.com/apps/email/integrations#integrations
    • New Inbound Email
  • Gmail: https://zapier.com/apps/gmail/integrations#triggers-and-actions
    • New Attachment
  • Outlook: https://zapier.com/apps/microsoft-outlook/integrations#triggers-and-actions
    • New Attachment
• SFTP
  • https://zapier.com/apps/sftp-by-zapier/integrations#help

​@Troy Tessalone we’re looking at Zapier to give more flexibility around deliveries than what’s currently available in Omni. Specifically the idea is to allow email deliveries from different domains based on content - we can only have one vanity domain in Omni currently.

​@clivado 

Concept would be to configure Omni delivery destination to send an email or to a SFTP Folder, then use that as the Zap trigger step.

Zap steps

1. Trigger: Gmail - New Attachment 
2. Action: Filter
3. Action: Gmail - Send Email

Zap steps

1. Trigger: SFTP - New or Updated File
2. Action: Filter
3. Action: Gmail - Send Email

That could work, thanks ​@Troy Tessalone!