curl --request POST \
  --url https://api.sandbox.bitwage.com/oauth2/token \
  --header 'Content-Type: application/json' \
  --data '
{
  "code": "<string>",
  "client_id": "<string>",
  "client_secret": "<string>",
  "grant_type": "authorization_code"
}
'

{
  "access_token": "<string>",
  "user_id": "<string>",
  "company_id": "<string>"
}