Founders building multi-platform software rarely sell through a single payment provider. You might sell web subscriptions through Stripe or Polar, while your mobile apps monetize via in-app purchases processed through Apple and Google via RevenueCat.
Combining these streams into a single, trustworthy Monthly Recurring Revenue (MRR) figure is surprisingly treacherous.
First is the definition problem. Annual subscriptions must be normalized by dividing the base fee by 12. Quarterly subscriptions must be divided by 3. Free trials must be strictly excluded until first payment collection, while grace-period past-due subscriptions must be accurately telemetry-flagged.
Second is currency normalization. If a customer in Tokyo pays 10,000 JPY and a customer in Berlin pays 49 EUR, summing numbers as raw floats produces rounding errors and currency mismatch. WallMRR calculates all monetary amounts in integer minor units (cents, yen, fils) and converts them into your display currency using daily reference rates.
Finally is resilience: when a payment provider suffers an API outage, WallMRR never turns your screen into a red error page. The wall preserves the last verified number, badges it with an honest stale marker, and seamlessly reconciles as soon as connectivity resumes.