Free ISP Billing Software in 2026: What Kenyan ISPs Really Need to Know

"Free ISP billing software" is one of the most searched terms by ISP owners — and for good reason. ISP software can be expensive, especially when you're starting out or running a lean network. But 'free' in software rarely means what it says, and for ISP billing specifically, the hidden costs can be substantial.

This is an honest, unsponsored breakdown of every free ISP billing software option available in 2026 — what they offer, what they don't, and what they actually cost when you factor in server infrastructure, engineering time, and the features you'll still need to build yourself.

Free ISP Billing Software That Actually Exists in 2026

There are four categories of 'free' ISP billing software, and they're very different from each other:

1. ZAL ISP Management System (Open Source)

ZAL ISP Management System is a PHP-based open-source ISP billing system with MikroTik API integration. It supports PPPoE subscriber management, invoice generation, and basic reporting. It's one of the most widely forked ISP billing repositories on GitHub.

What it includes: MikroTik API integration, PPPoE subscriber management, basic invoice generation, plan management, and a simple admin dashboard.

What it doesn't include: M-Pesa STK Push (or any payment gateway), automated billing/suspension, hotspot captive portal, SMS notifications, customer self-service portal, or commercial support. Active development is slow.

2. FreeRADIUS (Authentication Only — Not a Billing System)

FreeRADIUS is an authentication server, not billing software. It handles the RADIUS protocol that grants or denies internet access to PPPoE and Hotspot subscribers. It's free, open-source, and used by virtually every ISP worldwide. But FreeRADIUS alone provides zero billing functionality — you still need subscriber management, invoicing, and payment processing on top of it.

3. WHMCS (Not Free, Not Designed for ISPs)

WHMCS is a web hosting billing platform sometimes repurposed for ISPs. It is not free — it starts at $15.95/month USD. It is also not designed for ISPs: MikroTik and RADIUS support require paid third-party plugins, and M-Pesa integration is not available. We include it here because it comes up in ISP billing searches, but it's not a genuine option for most Kenyan ISPs.

4. Homegrown Scripts, Excel, and Cobbled-Together Workflows

Many ISPs build their own billing systems using Python scripts, Google Sheets, M-Pesa API, and MikroTik API calls. This is 'free' in the sense that the software costs nothing. But it requires significant development time, breaks when payment APIs update, and creates a single point of failure — usually the developer who built it.

The True Cost of Free ISP Billing Software

When you choose a self-hosted open-source solution like ZAL, the software license is free — but you need to budget for:

• VPS or server hosting: KES 2,000–6,000/month for a reliable server (shared hosting is not appropriate for ISP billing systems that need 24/7 uptime)
• SSL certificate and domain: KES 1,500–4,000/year
• Setup and configuration time: 20–40 hours to install, configure, customise, and test — at KES 3,000–6,000/hour for a competent developer = KES 60,000–240,000 one-time
• M-Pesa integration (build your own): ZAL includes no payment gateway. Implementing Safaricom Daraja API STK Push from scratch: 30–60 hours = KES 90,000–360,000
• Ongoing maintenance: 5–15 hours/month for updates, security patches, bug fixes, and server maintenance = KES 15,000–90,000/month
• No commercial support: When billing goes down at 11pm on month-end, there's no support team to call

Feature Gaps: What Free ISP Billing Software Misses for Kenyan ISPs

Total Cost of Ownership: Free vs Paid (First 12 Months)

The numbers are stark. For a 100-subscriber Kenyan ISP, 'free' ISP billing software costs 25x more in Year 1 than a paid managed platform — when you account for the engineering work required to deploy, integrate M-Pesa, and maintain the system. The gap narrows at very high subscriber counts, but for most ISPs under 500 subscribers, paid SaaS is significantly cheaper.

When Free ISP Billing Software Actually Makes Sense

Free and open-source ISP billing software makes genuine sense when:

• You have a full-time developer on staff who can build, maintain, and support the system as part of their regular role — not as a side project
• Your subscribers do not use M-Pesa (rare in Kenya, but possible for enterprise B2B ISPs with bank transfer billing)
• You want complete infrastructure ownership and accept the engineering cost as a strategic trade-off
• You're operating at very large scale (1,000+ subscribers) where the per-subscriber cost of SaaS becomes significant relative to a single developer's salary
• You're in a market with no good SaaS option — which is increasingly rare, especially in East Africa

For the vast majority of Kenyan ISPs — especially those under 500 subscribers without a dedicated engineering team — free ISP billing software is not actually cheaper than paid software. It's just a different way of paying, with worse unit economics.

The Bottom Line: Our Recommendation by Subscriber Count

1. 1Under 200 subscribers: Use Netily's metered plan (KES 500/month base + KES 20/subscriber). The 14-day free trial gives you full access before committing. Total cost at 100 subscribers: KES 2,500/month.
2. 2200–500 subscribers: Netily remains the most cost-effective option. At 300 subscribers you're paying KES 6,500/month — still a fraction of what maintaining a self-hosted solution costs.
3. 3500–1,000 subscribers: Evaluate Netily's Enterprise plan for custom pricing, or Splynx with a custom M-Pesa integration if you need specific enterprise features not available in Netily.
4. 41,000+ subscribers with a dev team: A self-hosted solution or custom-built system becomes worth evaluating — the per-subscriber cost of SaaS starts to compete with engineering cost at this scale.