Replace FreeSWITCH and Twilio with one Rust-native communications stack.
For ISPs, telcos, MVNOs, and service providers who need unified voice, messaging, and OSS or BSS without paying a per-message tax to a foreign cloud, and without keeping a FreeSWITCH expert on staff.
Stack at a glance
- ~517K
- Lines of Rust (Voice)
- 13
- BitsPath services
- 5+
- Router vendors (ISPChamp)
- <500ms
- Sotto turn latency
What is the communications stack?
Four products, one operational surface.
The KaritKarma communications stack is four shipped products composed against the day-to-day reality of an ISP or telco operator in Bangladesh. BitsPath is the unified communications cloud (voice, mail, SMS, WhatsApp, CRM, analytics). BitsPath Voice is the pure-Rust carrier-grade PBX that sits underneath it. ISPChamp is the software-defined BNG plus full OSS and BSS for subscriber operations. Sotto is the voice AI front-end you upsell to your commerce sub-tenants.
All four inherit Wenme identity, Darwan authorization, Professional Vault storage, and the shared audit chain. One login, one log surface, one procurement cycle.
The problem
Communications infrastructure should not be this painful.
FreeSWITCH is a maintenance tax
Large C codebase, constant security patches, scarce specialists who charge a premium. BitsPath Voice replaces it end-to-end with memory-safe Rust, multi-tenant by design.
Twilio bills grow without a ceiling
Per-message pricing with no upper bound. BitsPath BYOP lets you connect your own SMS, email, and WhatsApp providers. You pay provider rates directly, with zero delivery markup from us.
Hardware BRAS is a single point of failure
ISPChamp's software-defined BNG replaces six-figure Cisco and Juniper boxes with VPP and DPDK on commodity x86. Scales horizontally, fails partially, costs a fraction.
Fragmented tools, fragmented data
Voice in one tenant, SMS in a second, CRM in a third, ticketing in a fourth. BitsPath unifies every channel against a single contact record and shared analytics surface.
The products
Four shipped products, one platform underneath.
BitsPath
Unified Communications Cloud
Voice PBX, webmail, SMS, WhatsApp, CRM, campaigns, inbox, and analytics. One platform that replaces FreeSWITCH, Twilio, HubSpot, and Zendesk. Bring your own SMS, email, and WhatsApp providers with zero delivery markup.
BitsPath Voice
Pure-Rust Carrier-Grade PBX
About 517,000 lines of Rust across 10 crates. SIP RFC 3261 over UDP, TCP, TLS, WS. RTP and SRTP with NAT latching. B2BUA call engine, SIGTRAN SS7 stack (SCTP, M3UA, SCCP, TCAP, MAP) for cellular SMS. FreeSWITCH removed.
ISPChamp
Software-Defined BNG and ISP Operations
Complete OSS and BSS with a software vBNG (VPP and DPDK) that replaces hardware BRAS. Multi-vendor routing (MikroTik, Cisco, Juniper, Huawei, ZTE), RADIUS, OLT management, CGNAT compliance, bKash and Nagad checkout.
Sotto
Voice AI for Restaurants and Storefronts
Voice and SMS AI that answers the storefront phone in under 500ms. Useful when your communications customer also runs commerce. UK Big 14 allergens enforced, GDPR-aware, integrates with Square, Toast, Clover.
Why KaritKarma
Built by people who run a network.
APNIC member AS 64005. Own /24 IPv4 block (103.139.235.0/24). Tier-3 data centre in Dhaka, active-active to Sirajganj DR over our own BGP transit. We do not just write the software, we run a network on it.
Pure-Rust PBX, no C runtime
BitsPath Voice is end-to-end Rust. Memory-safe by construction, no buffer-overflow class of CVE, zero-downtime upgrades. No more 02:00 security-patch firefighting on a FreeSWITCH box.
BYOP, zero delivery markup
Bring your own SMS, email, and WhatsApp providers (Banglalink, GP, Robi, Postal, Twilio, Vonage, Meta WABA). You pay provider rates directly. We do not take a per-message cut.
Software-defined BNG on x86
Replace six-figure hardware BRAS with VPP and DPDK on commodity x86. Scale subscriber capacity by adding nodes, not by writing a Cisco purchase order.
Voice AI for your commerce tenants
Sotto answers the storefront phone for restaurants, clinics, and storefronts you serve. Sub-500ms turn-taking, integrates with Square, Toast, Clover. A managed-service upsell.
KaritKarma vs the alternatives
What this stack replaces.
Side-by-side against the legacy or Western SaaS option that communications buyers in Bangladesh evaluate first.
| Capability | KaritKarma | Legacy or imported |
|---|---|---|
| Pure-Rust carrier PBX (memory safe) | BitsPath Voice | FreeSWITCH (C), Asterisk (C) |
| BYOP SMS, email, WhatsApp (zero markup) | BitsPath | Twilio markup, per-message |
| Software-defined BNG on x86 | ISPChamp (VPP and DPDK) | Cisco ASR, Juniper MX |
| bKash and Nagad subscriber billing | First-party in ISPChamp | Per-bank integration project |
| Single contact record across channels | BitsPath unified CRM | HubSpot plus Zendesk plus Twilio |
Attributed claims: BitsPath Voice line counts and crate structure sourced from the bitspath-voice repository per the BitsPath Voice product page. ISPChamp router-vendor coverage and software vBNG validated in production at Bangladesh ISP tenants. Latency claims for Sotto verified end-to-end against Groq Llama 4 Scout and Deepgram Aura 2 pipelines.
Buyer questions
Questions network teams ask first.
Six written answers so the technical briefing call starts on substance.
- What is the KaritKarma communications stack?
- Four products composed against the operational reality of an ISP, telco, or service provider. BitsPath is the unified communications cloud (voice, mail, SMS, WhatsApp, CRM, campaigns, analytics). BitsPath Voice is the pure-Rust carrier-grade PBX underneath it. ISPChamp is the software-defined BNG and full OSS and BSS for ISPs. Sotto is voice AI for the commerce sub-tenant on your network. All four inherit Wenme identity and Darwan authorization out of the box.
- How does BitsPath replace FreeSWITCH and Twilio?
- BitsPath is a unified communications platform with 13 .NET microservices for the orchestration layer plus BitsPath Voice (about 517,000 lines of pure Rust across 10 crates) for the carrier PBX. SIP over UDP, TCP, TLS, WS, plus RTP and SRTP, plus SIGTRAN SS7 for cellular SMS. The BYOP model lets you connect your own SMS, email, and WhatsApp providers with zero per-message markup, replacing Twilio's variable pricing.
- Can I migrate from FreeSWITCH to BitsPath Voice in place?
- Yes. BitsPath Voice speaks standard SIP, so existing SIP trunks and SIP phones work immediately. The migration is parallel-run: stand up BitsPath Voice next to FreeSWITCH, move extensions and trunks tenant by tenant, and decommission FreeSWITCH once the call records match. Our team owns the migration and signs off only when carrier MOS scores hold.
- What is ISPChamp?
- ISPChamp is a complete ISP operations platform with a software-defined BNG (VPP and DPDK on x86) that replaces hardware BRAS. It includes multi-vendor router orchestration (MikroTik, Cisco, Juniper, Huawei, ZTE), subscriber billing, RADIUS and TACACS+ authentication, OLT management for FTTH rollouts, CGNAT compliance logging, and bKash and Nagad checkout. Multi-tenant SaaS for Bangladesh ISPs or single-tenant on-prem.
- Where does Sotto fit on a communications stack?
- Sotto is the voice AI layer for any commerce sub-tenant your ISP or telco serves: restaurants, storefronts, clinics. Sub-500ms voice plus SMS turn-taking, UK Big 14 allergens enforced as a hard conversation gate, GDPR scheduled erasure, and direct write-back to Square, Toast, Clover, and Stripe. Useful when a managed service customer wants a voice front-end without building one.
- Is KaritKarma actually an APNIC member or just hosting on someone else's network?
- APNIC member AS 64005, with our own /24 IPv4 block (103.139.235.0/24) and IPv6 allocation, running active-active across a Tier-3 data centre in Dhaka and a Sirajganj DR site over our own BGP-routed transit. Identity, authorization, and communications workloads sit on the wires we own.
Ready to unify the communications stack?
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