I’m developing a Node.js application using Express to handle Shopify webhooks for product updates and creations. My goal is to verify the HMAC signature provided by Shopify to ensure the request’s integrity. However, I’m encountering a persistent issue where the generated HMAC in my application does not match the HMAC provided by Shopify.

I have some difficulty in updating an existing metafield with Shopify API. Each time, I received an error, advising me that the variant already exists… so it’s not recognized to Update.