dwolla - passing the state parameters through the OAuth flow -

we have multi-tenant application (accountingsuite.com) , want have connect dwolla button in application.

the button open:

https://www.dwolla.com/oauth/v2/authenticate?client_id={client_id}&response_type=code&redirect_uri={redirect_uri}&scope={scope}&state={instance_id}

notice there state parameter @ end identifying instance in our multi-tenant app. after successful authentication response uri needs contain state parameter, otherwise it's impossible find out instance sent connect request. state parameter stripped in return.

this pretty standard oauth flow (see, example stripe).

please let me don't right, or pass through state parameter in oauth flow.

while dwolla doesn't support state parameter, alternative, can specify state parameter querystring variable in return_uri.

for example, if used return uri:

http://www.example.com/somepage?state=foobar 

after granting permissions application on dwolla, user redirected application via:

http://www.example.com/somepage?state=foobar&code={oauth verification code}