Lago Billing - Open-source alternative to Stripe Billing and Chargebee

FLEX - An in-app debugging and exploration tool for iOS.

Metronome - Metronome helps software companies launch, iterate, and scale their usage-based business models, with billing infrastructure that works at any size and stage.

Citizenserve Code Enforcement - » Code Enforcement Software |

Chargebee - Chargebee lets you manage subscriptions and payments at scale, handle custom recurring billing scenarios, reduce subscription churn and simplify accounting.

Photo Evidence Pro - Other Public Safety