How to pass user id values to Stripe for use once payment has succeeded

I have an angular app with an express (typescript) backend. Each user has a unique user id and once payment has succeeded I want to update that user in the database to reflect that they are a paying member. It seems like I am going to be wanting to make use of Stripe events/webhooks once payment has succeeded, but my question is once payment has succeeded how does the webhook that's being called know what the user id is so I can record it? It seems that I am simply linking the user to Stripes page they generated for me when users go to pay without passing any metadata to it so I'm not sure how to keep track of which user has actually paid when the webhook for payment succeeded has been called. Thanks for any help.

As you’ve mentioned, you can pass metadata, on the PaymentIntent creation. With Metadata, you can attach key-value pairs to specific objects and store this additional information on it. In your case, this would be the easiest solution. However, you mentioned you did not want to use Metadata and an alternative would be to create a customer. Then, pass the customer id on the PaymentIntent creation. When you get your payment_intent.succeeded event you’d map the customer object id to the user id in your database.