Sadeed

[meager umbra]

Could you please provide more details? start date of what ?

[snow ruin]

I am creating a checkout session in subscription mode and I want to set a start date for it (the subscription)

??

[meager umbra]

Nope you can't set the in Checkout Session APIs

Here is what you can set instead:
https://stripe.com/docs/api/checkout/sessions/create#create_checkout_session-subscription_data

Other wise you need to use Elements and Subscription APis in order to achieve this