The open-source community continues to drive significant innovation across various domains—transforming not only software development but also the way businesses communicate, manage accounts, and handle customer billing. In the rapidly evolving landscape of Voice over Internet Protocol (VoIP), billing systems serve as the backbone of operational efficiency for telecom operators, service providers, and open source unified communication platforms.

As we enter 2025, the demand for flexible, secure, and cost-effective VoIP billing systems has intensified. Whether it's wholesale billing for carriers or subscription-based billing for residential and enterprise clients, open-source VoIP billing solutions remain a compelling choice for businesses of all sizes.

In this article, we present a comprehensive review of the top 5 open-source VoIP billing systems of 2025. These solutions are ranked based on their GitHub stars, update frequency, community engagement, code maturity, and relevance to modern VoIP infrastructure.

Top 5 Open Source VoIP Billing Systems in 2025

1. PyFreeBilling

GitHub:github.com/pyfreebilling
License: AGPLv3
Backend Stack:Kamailio + FreeSWITCH + PostgreSQL

PyFreeBilling leads the list in 2025 due to its modern architecture and high scalability. Tailored for wholesale VoIP providers, it also supports residential and business models. It efficiently handles high call volumes with advanced routing, rate management, and fraud detection capabilities.

Features:

• Real-time billing engine with carrier-grade reliability

• Multilingual, responsive web interface for admins and resellers

• Rate management with import/export tools

• LCR (Least Cost Routing) engine

• Compatible with Kamailio, FreeSWITCH, and RTPProxy

• REST APIs for easy integration with CRM or ERP systems

• Integration-ready with external radius and accounting systems

PyFreeBilling is particularly known for its ability to support massive CDR processing, making it ideal for telecom carriers and VoIP wholesalers with global operations.

2. A2Billing (Updated Forks Active in 2025)

GitHub:github.com/Star2Billing/a2billing
License: GPLv2
Backend Stack: Asterisk + MySQL

Although A2Billing is a more mature project, updated forks and community patches in 2025 have revived interest in this platform. It is popular among calling card operators, residential VoIP providers, and SIP trunk resellers.

Features:

• Inline billing with support for prepaid/postpaid modes

• Multi-currency and multilingual support

• Detailed CDR generation, reporting, and invoice management

• Agent and reseller portal with commission settings

• Fraud control mechanisms and balance management

• Integration with payment gateways such as PayPal and Stripe

Its classic GUI and solid Asterisk integration make it a good fit for traditional deployments where simplicity and reliability are key.

3. ASTPP (A Smart TelePhony Platform)

GitHub:github.com/iNextrix/ASTPP
License: Open Source + Commercial Add-ons
Backend Stack: FreeSWITCH + MongoDB/MySQL + Redis

ASTPP continues to dominate in 2025 with its Version 6 and beyond, offering powerful billing and telephony services in a modular format. Designed as a full-featured telephony ecosystem, it is more than just a billing platform—it’s a complete smart VoIP solution.

Features:

• Integrated billing with dynamic rating and taxation

• LCR (Least Cost Routing), failover routing

• DID management, call conferencing, fraud detection

• Multi-tenant support with ACL (Access Control Lists)

• Customer, reseller, and admin dashboards

• Highly extensible with a plugin-based architecture

• WebRTC support and JSON API for integration

ASTPP is ideal for ITSPs, multi-tenant VoIP providers, and startups that want a comprehensive FreeSWITCH-based solution.

4. MagnusBilling

GitHub:github.com/magnusbilling/magnusbilling6
License: GPLv3
Backend Stack: Asterisk + MariaDB + PHP

MagnusBilling remains a robust and widely adopted open-source billing solution for Asterisk-based deployments. With continuous updates and a strong community, it offers a secure and scalable platform for resellers and service providers.

Features:

• Multi-level reseller and customer access

• Real-time call monitoring and billing

• Integrated support for SMS, DID management, and rate tables

• Voicemail, IVR, and call forwarding features

• Full API access and report exports

• Detailed CDRs with buy/sell margin calculations

In 2025, MagnusBilling has enhanced support for SIP trunk management and multi-country deployments, making it an excellent choice for regional VoIP operators.

5. CDR-Stats

GitHub:github.com/cdr-stats/cdr-stats
License: BSD
Backend Stack: Django + PostgreSQL + Celery

CDR-Stats stands apart for its data analysis and visualization focus. It is a CDR mediation and reporting tool rather than a traditional billing platform but is frequently used in tandem with other VoIP billing systems for deep analytics.

Features:

• Centralized CDR aggregation from multiple sources

• Flexible call rating and cost analysis

• Web-based dashboards with powerful filtering

• Email alerts and PDF/CSV report generation

• Works with Asterisk, FreeSWITCH, Kamailio, and Cisco systems

• Multi-tenant and multi-provider support

For organizations that prioritize reporting, auditing, and historical billing analysis, CDR-Stats is an indispensable tool.

Conclusion

The year 2025 continues to demonstrate the strength and vitality of the open-source VoIP billing ecosystem. Whether you're a large-scale VoIP carrier, a mid-sized ITSP, or a startup exploring the telecom space, these billing systems provide flexibility, cost savings, and scalability.

Each platform has its strengths:

• PyFreeBilling and ASTPP shine in scalability and modern architecture.

• A2Billing and MagnusBilling remain reliable and community-driven for Asterisk-based deployments.

• CDR-Stats complements any billing system with its analytics edge.

Need Expert Guidance?

ICT Innovations—a trusted name in open-source telephony—specializes in deploying and customizing these VoIP billing solutions. Whether you require integration, scaling, security hardening, or feature enhancements, ICT Innovations offers tailored services to match your needs.

Contact us today for expert consultation and VoIP system deployment.