Plan changes created billing disputes
When customers upgraded or downgraded mid-cycle, the business had no consistent way to calculate what they actually owed, leading to manual corrections and customer confusion.
SAAS MVP CASE STUDY
Subscription billing that handles plan changes and failed payments correctly
We built a subscription management platform focused on the two places billing usually breaks down: mid-cycle plan upgrades and downgrades, and what happens when a recurring payment fails.
▣ Proration handled automatically Mid-cycle upgrades and downgrades bill correctly
♙ Structured dunning workflow Failed payments get retried on a defined schedule
✦ [CONFIRM TIMELINE] From kickoff to a working MVP
Two problems that make subscription billing fragile
Most subscription platforms can charge a card on a schedule. Fewer of them get the edge cases right: what should a customer be charged if they upgrade from a monthly to an annual plan halfway through the month, and what should happen — automatically, without a human chasing it — when a renewal payment is declined.
This MVP was scoped specifically around those two problems: proration logic for plan changes, and a dunning process for payment failures, rather than trying to cover every billing scenario a mature platform might eventually need.
▥IndustryB2B SaaS / Billing
◇ProductSubscription billing platform
♙AudienceSaaS businesses managing recurring plans and billing
⌁Delivery[CONFIRM TIMELINE]
The Challenge
Failed payments were handled ad hoc
A declined card meant someone on the team had to notice, follow up manually, and hope the customer updated their payment details before access was cut off or extended too long.
No visibility into subscription health
There was no clear view of which customers were mid-retry, which had just changed plans, or which were at risk of involuntary churn from a failed payment.
What We Can Identified
A billing core built around correct proration and a structured recovery path for failed payments, not a general-purpose plan catalog.
Prorated plan upgrades and downgrades
Customers who change plans mid-cycle are billed or credited the correct prorated amount automatically, removing the need for manual billing adjustments.
Configurable dunning schedule
Failed payments trigger a defined sequence of retries and customer notifications, so recovery attempts happen consistently instead of depending on someone noticing.
Subscription status states
Each subscription shows a clear state — active, past due, in retry, canceled — giving the team an accurate picture of billing health at any moment.
Payment failure notifications
Customers are notified automatically when a payment fails and when a retry is scheduled, reducing surprise cancellations caused by an out-of-date card.
Plan change history per customer
Every upgrade, downgrade, and proration calculation is logged against the customer's account, giving support a clear record when a billing question comes in.
Grace period configuration
The business can define how long a past-due subscription stays active before access is suspended, balancing recovery time against revenue risk.
How MVPHUB Delivered It
1
◇ Billing logic discovery
We worked through the specific proration and dunning rules the business needed, rather than assuming a generic billing model would fit.
2
✎ MVP scope definition
We scoped the MVP tightly around plan-change billing and payment-failure recovery, leaving broader billing features for later validation.
3
✦ Core build
We built the proration engine, subscription state machine, and dunning scheduler as the connected core of the platform.
4
♢ Scenario testing
We walked through real upgrade, downgrade, and failed-payment scenarios to confirm the calculations and retry timing matched expectations.
5
⌁ MVP handover
We delivered a working platform ready to manage live subscriptions, with billing edge cases already handled rather than left for later.
Plan changes bill correctly and failed payments get chased automatically, without manual intervention.
Engineering Behind The Experience
Deterministic proration logic
Proration calculations follow a defined, testable rule set rather than being estimated or adjusted manually per case.
Stateful subscription lifecycle
Each subscription moves through explicit states, which is what makes automated dunning and grace periods possible without manual tracking.
Built for iteration
The MVP focused on the highest-risk billing scenarios first, leaving room to extend plan catalogs or reporting once the core logic was validated.
The Outcome
Before: Billing that broke under real usage
× Mid-cycle plan changes required manual billing corrections
× Failed payments depended on someone noticing and following up
× No consistent grace period before access was affected
× No record of why a customer was charged a specific amount
After: Billing logic that holds up automatically
✓ Plan changes are prorated correctly without manual work
✓ Failed payments trigger an automatic retry and notification sequence
✓ Grace periods are applied consistently before suspension
✓ Every charge is traceable to a specific plan change or renewal
What This Unlocks
Fewer billing disputes from mid-cycle plan changes
Reduced involuntary churn from unresolved payment failures
A clear, auditable billing history per customer
Getting the hard parts of subscription billing right
Most billing problems don't show up on day one — they show up the first time a customer upgrades mid-cycle or a card gets declined.
By building proration and dunning logic into the core of the platform from the start, this MVP avoids the manual corrections and quiet churn that come from treating those cases as afterthoughts. [CONFIRM FEATURE] and [CONFIRM FEATURE] are natural next steps as the business validates the model against real subscriber behavior.
THE MVPHUB PRINCIPLE
"Billing logic that only works for the simple case isn't done — it's untested.
"
Building or fixing a subscription billing system?
If plan changes or failed payments are creating manual work or quiet churn, we can help you validate an MVP that handles the billing logic correctly from the start.
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