Short answer: "free" ISP billing software usually means FreeRADIUS, which is genuinely free and open source — but FreeRADIUS is an AAA server, not a billing platform. GST invoicing, partner/LCO commission tracking, payment-gateway collection, OLT/TR-069 monitoring, and WhatsApp notifications all have to be built on top of it, by you, with your own time. A paid managed platform like NowaCRM replaces that build-and-maintain project with a published per-subscriber price (₹10 down to ₹3.50/subscriber by volume, ₹500/month minimum) and a 1-month free demo to try before committing. The real comparison isn't "free vs ₹X" — it's "your engineering time vs a published subscription."
What "free ISP billing software" usually actually means
Search for free ISP billing software and the honest answer, almost every time, is FreeRADIUS — the open-source RADIUS daemon that handles authentication, authorization, and accounting (AAA) for PPPoE and IPoE subscribers. It costs nothing to download, nothing to run, and nothing in license fees, which is exactly why it shows up at the center of almost every "free" ISP setup. What it is not is a billing system: FreeRADIUS has no concept of a subscriber plan, an invoice, a GST rate, a payment gateway, or a partner wallet. Those are commercial-layer concepts that sit on top of AAA, and "free" stops covering them the moment you need one.
The real DIY stack: what you actually have to build
A working free ISP billing setup is really five separate projects stacked on top of FreeRADIUS, not one download: (1) a SQL schema for subscribers, plans, and invoices — usually hand-written against MySQL/MariaDB since FreeRADIUS ships only its own radcheck/radreply/radacct tables; (2) GST-compliant invoice generation with correct CGST/SGST/IGST splits, which is easy to get subtly wrong and expensive to discover during a tax filing; (3) a Change-of-Authorization (CoA) layer that translates a billing event — payment received, plan expired, fair-usage cap hit — into the correct vendor-specific RADIUS attribute for your NAS hardware, since MikroTik, Nokia, Cisco, and Huawei all expect different attributes for the same "change this subscriber's speed" action (see our FreeRADIUS AAA setup guide for exactly how deep this gets); (4) payment collection — either manual bank-transfer reconciliation or your own integration against a gateway's API; and (5) ongoing maintenance of all of the above as your NAS fleet grows, firmware updates change RADIUS behavior, and your subscriber base crosses thresholds that expose scaling issues nobody budgeted time for.
None of this is impossible. Plenty of small ISPs run exactly this stack today, maintained by one technically-capable owner or a single in-house developer. The honest framing is that it is a real, ongoing engineering commitment, not a one-time setup task — which is the part "free" pricing comparisons tend to leave out entirely.
Where free/open-source stacks typically fall short for a growing ISP
Four gaps show up repeatedly once an ISP running a DIY stack starts to scale past "one person can keep this in their head":
GST compliance. A generic open-source billing script rarely models India's CGST/SGST/IGST split correctly from day one, and getting tax logic wrong is the kind of mistake that surfaces at the worst possible time — during a GST filing or an audit, not during testing. A managed platform's tax engine is built from reusable, independently-rounded tax components with inclusive/exclusive pricing modes, covering the same statutory conventions GST and EU-style VAT both need, so this isn't something you're reverse-engineering under deadline pressure.
Partner and LCO commission tracking. If your ISP sells through resellers or local cable operators, "free" has no answer for crediting a partner's wallet automatically when their subscriber pays, or calculating commission without a spreadsheet. This is the exact dispute pattern — nobody trusts the commission number because there's no shared ledger — that our partner commission management guide covers in depth.
Payment collection at scale. Manual bank-transfer reconciliation works for a handful of subscribers. Past a few hundred, matching payments to invoices by hand becomes the single biggest operational drag on a small billing team — the reason a payment gateway integration layer that auto-matches webhooks to invoices exists as a dedicated product category at all.
Network visibility beyond RADIUS. OLT/ONU health monitoring and TR-069 zero-touch CPE provisioning are entirely separate systems from AAA — FreeRADIUS has no opinion on either. A DIY ISP typically runs these as yet another unconnected tool, if it runs them at all, rather than as part of one subscriber record.
TCO comparison: DIY/open-source stack vs a managed paid platform
| Cost category | DIY / open-source (FreeRADIUS-based) | Managed paid platform (NowaCRM) |
|---|---|---|
| Core AAA (auth/accounting/CoA) | Free (FreeRADIUS), but you write and maintain the per-vendor CoA translation yourself | Included — multi-vendor CoA translation and retry queue built in |
| GST invoicing engine | Hand-built; tax-split errors are a real audit risk until proven otherwise | Included — configurable tax groups, CGST/SGST/IGST, inclusive/exclusive modes |
| Partner/LCO commission tracking | Not a FreeRADIUS concept — spreadsheets or a custom build | Included — automatic wallet credit + commission ledger |
| Payment gateway collection | Your own integration per gateway, or manual-only | Included — eight India-focused gateways plus manual/wallet/partner paths, auto-reconciled |
| OLT/TR-069 network visibility | Separate, usually unconnected tooling (if run at all) | Included — SNMP OLT monitoring and GenieACS-backed TR-069 ACS tied to the same subscriber record |
| Hosting | Your VPS cost, your responsibility | Included in the subscription |
| Security patching & uptime | Your responsibility, on your schedule | Managed, with a 99.9% uptime SLA on enterprise plans |
| Support when something breaks | Whoever built it, if they're still around | 24/7 ISP-specialist support included |
| Published price | No license cost, but no published total either — cost is scattered across hosting + dev time | ₹10 down to ₹3.50/subscriber/month by volume, ₹500/month minimum, published on the pricing page |
What NowaCRM actually costs, for comparison
Rather than argue in the abstract, here is the real number: NowaCRM uses cumulative tiered per-subscriber pricing — the first 200 subscribers at ₹10 each, the next 800 at ₹8 each, and so on down to ₹3.50/subscriber at the top tier, with a ₹500/month minimum. A 500-subscriber ISP works out to about ₹4,400/month with every feature included — billing, RADIUS AAA, GST invoicing, partner wallets, payment gateways, and support — and no add-on fees for any of it. Annual billing adds a 20% discount. Every new ISP also gets a 1-month free demo with full platform access and no credit card required, specifically so this comparison doesn't have to be taken on faith — the pricing calculator shows the exact cost at your own subscriber count before you commit to anything.
When DIY genuinely makes sense
A free, self-hosted FreeRADIUS stack is a legitimate choice for a very small ISP — think a few hundred subscribers, one NAS vendor, simple prepaid plans, no partner network yet — run by someone with the development skills to build and maintain it, or treating the project as a deliberate learning exercise. Plenty of small operators run exactly this today, successfully. The honest caveat is that it stays manageable only as long as the business stays simple; every dimension that makes an ISP grow — a second NAS vendor, a reseller network, GST scrutiny, payment-gateway scale — adds a project of its own to the DIY pile.
When paid, managed billing pays for itself
The crossover point is usually one of: adding a partner or LCO network (commission tracking becomes unmanageable by spreadsheet), a GST filing that exposes a tax-logic gap, enough subscribers that manual payment reconciliation eats a full-time role, or simply wanting 24/7 support instead of being the single point of failure for your own billing stack. At that point, a published per-subscriber price that already includes RADIUS, GST, partner tools, payment gateways, and OLT/TR-069 visibility is usually cheaper — in time, not just money — than continuing to build and patch a DIY system piece by piece.
See our ISP billing software for India page for the full GST and payment-collection feature set, the global ISP billing software overview for the currency- and tax-engine detail, and our FreeRADIUS AAA setup guide if you're evaluating exactly how much of the AAA layer you'd need to build yourself on the DIY path.
