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Question

Webhook custom request error "input is invalid"

  • July 22, 2025
  • 3 replies
  • 36 views

Hi Team,

I use postman and power automate for the identical copy paste payload and they all works fine. the issue here, for the section that i highlighted in yellow, Zapier may have done some formatting and i keep getting input is invalid.

 

If i omit the entire “custom_fields” segment (highlighted in yellow), the code goes through fine but that defeat the purpose.

 

data passthrough is false, unflatten is yes content-header is defined as application/json. the target system does not accept form data payload.

any idea why is this the case with zapier webhook? Thanks!

 

 

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3 replies

Troy Tessalone
Zapier Orchestrator & Solution Partner
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  • Zapier Orchestrator & Solution Partner
  • 34032 replies
  • July 22, 2025

Hi ​@Avelyn 

What is the link to the app API endpoint documentation you used to configure the API request in the Zap step?

 

 


DavidLGS
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  • Zapier Solution Partner
  • 208 replies
  • July 22, 2025

Are you sending the correct request for that endpoint in the configuration tab? i.e. GET, POST, PATCH, etc?


Troy Tessalone
Zapier Orchestrator & Solution Partner
Forum|alt.badge.img+14
  • Zapier Orchestrator & Solution Partner
  • 34032 replies
  • July 22, 2025

@Avelyn 

Do you have the correct Headers set?

Post more screenshots to give us more context.