Flexprice

Flexprice is an open-source, self-hosted web app and server that provides infrastructure for usage-based and hybrid pricing models. It functions as a server-side web application that handles the logic for metering, credits, and subscription management. It is designed for AI-native companies and SaaS teams that require real-time reporting and flexible monetization strategies to scale as their products evolve.

The software is deployed as a server that integrates with existing backend APIs, AI agents, or custom workflows. It processes usage data in real time to calculate pricing, apply credits, and generate invoices. Flexprice acts as a composable layer that can either stand alone or augment existing payment processors and CRM tools to manage entitlements and billing rules, ensuring that billing information flows into the systems a business already uses for accounting and customer management.

Key features

• Real-time usage metering for custom events like API calls or compute time
• Management of prepaid and promotional credit grants with automatic top-ups
• Support for seat-based, pay-as-you-go, and volume-tiered pricing plans
• Feature management to enforce entitlements and usage limits per customer
• Automated invoice generation based on aggregated usage data
• Per-customer pricing overrides and plan versioning
• Integration with external payment gateways, CRMs, and accounting tools

The architecture utilizes Go, PostgreSQL, ClickHouse, and Temporal to handle high-volume event streaming and aggregation. It is built for developers who want to avoid vendor lock-in and the complexity of building custom metering logic from scratch. By abstracting the calculation of usage and the enforcement of feature gates, it allows teams to modify pricing strategies in minutes without performing database schema migrations or writing complex migration scripts. The system can ingest data directly from data warehouses or analytics pipelines, providing transparency into usage and charges for both engineering and finance teams.

Flexprice is a developer-first billing engine that separates the logic of pricing and metering from the actual processing of payments.