REST API call with client certificate

[MarcoNoordam]

Hi,

How do I make a REST call which needs a client certificate (crt + key)?
I have it working in Postman, but can't figure out how to do this within AppSheet. 

Help much appreciated!

[WillowMobileSys]

If you are calling an external service FROM AppSheet, then you may want to refer to the articles below.  The terms "cert" and "key" may be referred to differently.

Introduction to webhooks 

Call a webhook from automation

[MarcoNoordam]

Thank you for your reply and links.
The only authentication mentioned in the documentation is related to Header-authentication, but my source demands a client-certificate/key.

Or do you suggest pasting the certificate-strings as http-header?

[WillowMobileSys]

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@MarcoNoordam wrote:

Or do you suggest pasting the certificate-strings as http-header?

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I think this depends on the external API service you are calling.  They must have some guidance on how you are expected to pass the authentication details.

[MarcoNoordam]

Calls to the API must be signed with a certificate.
https://ons-api.nl/nieuwe_koppeling/Ontwikkelen.html

Translated:
All calls to our APIs must be signed with the certificate that corresponds to the environment, in this case, your development certificate. How to set this up correctly will vary depending on the framework or platform; we cannot assist you with this.

Within postman I followed this guide
https://learning.postman.com/docs/sending-requests/certificates/

[WillowMobileSys · Accepted solution]

I see.  These are connection certificates.  They establish a secure communication channel between two entities, basically a VPN - Virtual Private Network.  Because it's private, it requires its own encryption/decryption keys which are provided by the certificate.

Unfortunately, AppSheet does not support this style of secured communications at this time. 

However, I believe you could implement Google App Scripts to handle this. Your app calls a script, passing the necessary arguments and the script in turn builds the JSON payload and calls the API.