Using variables for redirect uri

İs it possible to use variables for redirect uri.

Such as mywebsite.com/?var=12

As i am using a custom code in wp that needs to keep on using this var…

But when i return from patreon var is lost… and i get an error.

İs there a Way to overcome this.

Yes, you can put all your variables into an array (or whatever you use in your stack), then json_encode + base64 it and load it into the state= variable and then send it to the flow. You will get the state variable as it was sent and you can decode the array from it and use it in your app.