Best Usage-Based Billing Software for HTML

​Flexprice is an open source, developer-first platform designed to simplify metering, pricing, and invoicing for SaaS and AI products. It enables teams to build usage-based, credit-based, or hybrid pricing models with full control. Flexprice's real-time usage metering allows you to define granular events, such as API calls, compute time, or custom actions, and track them reliably, even at scale. It supports prepaid and promotional credits, auto top-ups, and expiration rules, all configurable without extra logic. Its flexible pricing engine lets you define and iterate on seat-based, usage-based, or hybrid plans, override them per customer, and adapt pricing over time without additional engineering effort. With built-in feature management, you can define Boolean, metered, and config features per plan and customer, enforcing limits directly in your backend. Flexprice generates accurate invoices from real-time usage, subscriptions, or credits.