billing-engine

Open-source, self-hosted billing for AI products: price tokens by model, sell prepaid credits, see margin per customer, and charge through Stripe without the Stripe Billing fee.

The Autonomous Revenue OS for Enterprise SaaS. Built with Next.js 15, PostgreSQL, Redis, and AI-driven growth agents.

Serverless utility rate engine on AWS: author bill calculations in a spreadsheet-like language (RDL) that transpiles to compiled Rust Lambda. React UI for rate authoring, plus batch processing for rate-case modeling across millions of bills.

A guide on how to sell your Plug-Ins to marketplace owners using Stripe

Advanced billing engine for Laravel: subscriptions, proration, usage metering, addons, credit notes, and pluggable invoice/tax drivers on PostgreSQL. Built for SaaS, IaaS, and usage-based products.

An enterprise-grade B2B SaaS subscription and customer management system featuring a state-driven billing engine, real-time metrics dashboards, and advanced filtering. Built as a high-performance monorepo with Java 25 / Spring Boot 4 and React 19 / Vite 8

Event-driven idempotent usage-based billing engine (POC v0.1). Ingest → idempotent process → versioned rating → aggregate → query → reconcile → MCP. Runnable locally (Docker; Kafka + Flink streaming tier), 100% line and branch coverage.

Agentic 3-way matching billing discrepancy engine detecting discrepancies across Purchase Orders, Quotes, and Invoices.

RevRecover : AI-Assisted Revenue Recovery & Billing Compliance Control Plane

Agent-Orchestrated Multi-Tenant EAV Database Architecture for Dynamic Subscription Management

Monorepo for a B2B Micro-Suite: asynchronous billing core with NestJS, BullMQ, and Prisma, plus future RevOps modules. Built with pnpm workspaces as a modular monolith.

Production-grade usage metering, quota enforcement, and billing engine built with FastAPI, PostgreSQL, and Stripe. Features exactly-once idempotency, micro-cent integer money math, and signature-verified webhook synchronization. FlyRank AI Engineering Capstone.

An object-oriented C# subscription & billing engine with automated grace period handling and dynamic discount calculations.