Overview

In the Kill Bill model, Subscriptions are associated with a Plan (defined in the catalog), and Plans are made of several PlanPhases. The idea behind the model is to accurately represent the transitions from different phases (e.g TRIALEVERGREEN) without requiring the system or user to take any actions. Subscriptions automatically transition from one PlanPhase to the next, as defined by the shape of the Plan and the clock moving forward.

When changing the Plan associated with a Subscription (e.g upgrading), the system needs to understand how to align phases from the original Plan to the new Plan to make sure the user ends up in the right phase. Let’s consider the following example with two similar Plans (silver-monthly and gold-monthly) both containing two phases: a 7 day TRIAL phase, followed by a monthly EVERGREEN (recurring forever until cancelled) phase.

  • On January 1st, a subscription is initially created with a silver-monthly Plan, and starts with the 7 day TRIAL period.

  • On January 4th, while the subscription is still in TRIAL, the user upgrades to a gold-monthly plan.

As a company offering those plans, you have the choice to define the behavior in this situation:

  1. You may want to restart a full new 7 day TRIAL period to allow the user to experiment, since the Plan is different.

  2. You may want to offer the user the remainder of the TRIAL period (4 days left).

  3. You may want to skip the TRIAL altogether, since the user already made up his mind. He liked the product and upgraded to gold-monthly, so he is already committed.

In order to provide this level of flexibility, the catalog contains alignment rules to specify the appropriate behaviors. These alignement rules apply both to operations that create Subscriptions (to decide on how to align an Add-On Plan with respect to the Base Plan) and also, as mentioned in the previous example, for change Plan operations. The Kill Bill Subscription Guide provides an overview of these alignments.

In addition to specifying alignment policies, our apis also allow you to specify a target PlanPhase. The specification of such a target PlanPhase can be used when creating a new Subscription or when changing a Plan. With the previously defined gold-monthly plan, we could create a subscription with a target PlanPhase set to EVERGREEN to make sure the user skips the TRIAL phase and directly starts on the EVERGREEN phase. Note that this is also achievable by creating more Plan entries in the catalog (e.g. a gold-monthly-notrial Plan), but this would force administrators to duplicate the plans, and may also be an issue from an analytics point of view, depending on how metrics are being computed.

In this section we look at several scenarios that illustrate possible behaviors of the system when a change Plan operation happens on a Subscription for which initial phase(s) were skipped at creation (by specifying a target PlanPhase).

Scenario 1a

In this scenario, the Plan for the original Subscription contains 2 PlanPhases, a TRIAL phase and an EVERGREEN phase, and the user skipped the TRIAL phase by specifying the EVERGREEN PlanPhase as the target. Later, a change of Plan happens, switching to another Plan containing one or more phases. The last PlanPhase in the new Plan is EVERGREEN, and the catalog is configured to use a START_OF_SUBSCRIPTION (or START_OF_BUNDLE) plan change alignment.

PlanAlignmentScenario1a

We can see that when the change occurs, the Subscription is realigned based on its start date and matched to the same target PlanPhase that was originally specified when creating the Subscription.

Scenario 1b

This scenario is similar to the previous one except that the catalog is configured to use a CHANGE_OF_PLAN plan change alignment.

PlanAlignmentScenario1b

In this case the Subscription is realigned based on the date of the change, and we ignore the target PlanPhase that was originally specified. We will see in a subsequent scenario that if the intent is to stay on EVERGREEN we can also specify a target PlanPhase when making the change operation.

Scenario 2a

In this scenario, the Plan for the original Subscription again consisted of 2 PlanPhases, a TRIAL phase and an EVERGREEN phase. Also as in Scenario 1a, the user skipped the TRIAL phase by specifying the EVERGREEN PlanPhase as the target. Later, a change of Plan happens, switching to another Plan containing one or more phases. However, this Plan does not include an EVERGREEN PlanPhase. The catalog is configured in this scenario to use a START_OF_SUBSCRIPTION (or START_OF_BUNDLE) plan change alignment.

PlanAlignmentScenario2a

Once again, when the change occurs, the Subscription is realigned based on its start date. However, because the original target PlanPhase does not exist in the Plan, we realign using the first PlanPhase of the new Plan.

Scenario 2b

This scenario is similar to the previous one except that the catalog is configured to use a CHANGE_OF_PLAN plan change alignment.

PlanAlignmentScenario2b

Here we realigned based on the date of the change, but we start from the first PlanPhase of the new Plan.

Plan Change with Target PlanPhase

In this section we look at the behavior of the system when the user specifies a target PlanPhase on a change Plan operation.

Scenario 1a

In this scenario we assume as usual that a Subscription was created using a Plan made of 2 PlanPhases, a TRIAL phase and an EVERGREEN phase, but the user did not skip any PlanPhase. Subsequently, the user decides to change to a a new Plan that has 3 PlanPhases, namely a TRIAL, a DISCOUNT and an EVERGREEN phase. The user specifies a DISCOUNT target PlanPhase when changing the Plan. The catalog is configured to use a START_OF_SUBSCRIPTION (or START_OF_BUNDLE) plan change alignment.

PlanAlignmentScenarioChange1a

The Subscription is realigned based on its start date. Since the change Plan operation specified a DISCOUNT target PlanPhase, we realign based on that PlanPhase.

Scenario 1b

This scenario is similar to the previous one except that the catalog is configured to use a CHANGE_OF_PLAN plan change alignment.

PlanAlignmentScenarioChange1b

In this case, the Subscription is realigned based on the date of the change Plan operation, but now it will start with the specified DISCOUNT target PlanPhase.

Summary

The use of aligment rules (as configured in the catalog) along with the ability to specify a target PlanPhase when creating a Subscription, or changing the Plan of an existing Subscription, provides users with a lot of flexibility.

This documentation has shown some basic scenarios that should guide developers to achieve the desired result. However, the number of possible use cases is quite large, and depends on the business logic required for each catalog. We strongly advise you to experiment, and to write tests specifc to each use case.