You can use this as a handy reference to all of the urls that Spreedly exposes to you, both via the web and via the API.
https://spreedly.com/[short site name]/subscribers/[customer_id]/subscribe/[subscription plan id]/[screen name for subscriber]
https://spreedly.com/[short site name]/subscriber_accounts/[spreedly token]
GET /api/v4/[short site name]/subscribers/[customer_id].xml
POST /api/v4/[short site name]/subscribers.xml
PUT /api/v4/[short site name]/subscribers/[customer_id].xml
POST /api/v4/[short site name]/subscribers/[customer_id]/complimentary_subscriptions.xml
POST /api/v4/[short site name]/subscribers/[customer_id]/complimentary_time_extension.xml
POST /api/v4/[short site name]/subscribers/[customer_id]/lifetime_complimentary_subscriptions.xml
POST /api/v4/[short site name]/subscribers/[customer_id]/credits.xml
POST /api/v4/[short site name]/subscribers/[customer_id]/fees.xml
POST /api/v4/[short site name]/subscribers/[customer_id]/change_subscription_plan.xml
POST /api/v4/[short site name]/subscribers/[customer_id]/stop_auto_renew.xml
POST /api/v4/[short site name]/subscribers/[customer_id]/subscribe_to_free_trial.xml
POST /api/v4/[short site name]/subscribers/[customer_id]/allow_free_trial.xml
GET /api/v4/[short site name]/subscribers.xml
GET /api/v4/[short site name]/subscription_plans.xml
POST /api/v4/[short site name]/invoices.xml
PUT /api/v4/[short site name]/invoices/[invoice token]/pay.xml
DELETE /api/v4/[short site name]/subscribers.xml
DELETE /api/v4/[short site name]/subscribers/[customer_id].xml