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
- ~120K
- Lines of Rust (Voice)
- 16
- BitsPath .NET services
- 5
- Router vendors (ISPChamp)
- <500ms
- Sotto latency budget
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.
BitsPath, BitsPath Voice, and ISPChamp inherit Wenme identity and Darwan authorization out of the box: one login, one permission model, one procurement cycle. Sotto ships self-contained with its own auth stack for its UK restaurant market.
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 120,000 lines of Rust across 10 crates plus the API server, with 1,500+ tests. 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, engineered to a sub-500ms time-to-first-audio budget. 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 with dedicated IPv4 and IPv6 blocks, announced over our own multi-homed BGP transit from a Tier-3 data centre in Dhaka, with a designated DR site. 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 on the telephony path. Memory-safe by construction, no buffer-overflow class of CVE. No more 02:00 security-patch firefighting on a FreeSWITCH box.
BYOP, zero delivery markup
Bring your own SMTP relay or Postal server for email, your own SMPP bind or aggregator for SMS, your own Meta WhatsApp Business account. 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. Engineered to a sub-500ms budget, 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 measured directly from the bitspath-voice repository. ISPChamp router-vendor coverage and the software vBNG data plane are verified in the ISPChamp codebase. Sotto's sub-500ms figure is its published time-to-first-audio engineering budget on the Groq Whisper, Llama 4 Scout, and Deepgram Aura 2 pipeline, not a measured production percentile.
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. BitsPath, BitsPath Voice, and ISPChamp inherit Wenme identity and Darwan authorization out of the box; Sotto ships self-contained with its own auth stack.
- How does BitsPath replace FreeSWITCH and Twilio?
- BitsPath is a unified communications platform with 16 deployable .NET services (14 services plus 2 gateways) for the orchestration layer plus BitsPath Voice (about 120,000 lines of pure Rust across 10 crates plus the API server) 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 SMTP relay, your own SMPP bind or aggregator, and your own Meta WhatsApp Business account 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, FreeRADIUS 3.2.7 authentication with RFC 5176 CoA, OLT management for FTTH rollouts across six vendor families, deterministic CGNAT with BTRC-format compliance logging, and bKash and Nagad checkout. Hybrid model: SaaS control plane with an on-prem appliance, so subscriber data stays in your NOC.
- 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. Voice plus 2-way SMS ordering engineered to a sub-500ms time-to-first-audio budget, 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 dedicated IPv4 /24 and IPv6 allocations, announced over our own BGP-routed multi-homed transit from a Tier-3 data centre in Dhaka, with a designated DR site. Identity, authorization, and communications workloads sit on the wires we own.
Ready to unify the communications stack?
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