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BitsPathLive . bitspath.com

Unified communications, owned end to end

One wire.
Every channel your business actually sends on.

BitsPath is the comms platform that doesn't make you choose between a CPaaS, a webmail provider, and a PBX vendor. Voice in pure Rust, SMS over a real SIGTRAN stack, per-tenant business email backed by Stalwart, WhatsApp Business Cloud, transactional email, and push, sitting under one CRM, one campaign engine, one agent inbox, and one Darwan permission set. Bring your own provider keys: your carrier rates stay between you and your carrier.

Open the platformWalk an engineer through it
  • Pure-Rust PBX, no FreeSWITCH
  • SIGTRAN/SS7 SMS in-tree
  • Stalwart webmail per tenant
  • Wenme OAuth 2.1 + Darwan
  • BYO carrier, BYO SMTP
  • MassTransit on RabbitMQ
POST /api/messaging/dispatch
202 Accepted
payload
{
  "tenant_id": "tnt_01HX...",
  "contact_id": "ctc_01HX...",
  "channels": ["voice","sms","email","mail","whatsapp"],
  "policy": "first-success",
  "template": "tpl_billing_overdue_v3"
}
routing
  • VOICEVoice / SIP:5060
  • SMS SMS / SIGTRAN:2775
  • EMAILEmail / SMTP:587
  • MAIL Webmail / JMAP:443
  • WHATSWhatsApp Cloud API:443
19
.NET projects
14 services + 2 gateways + 3 libs
152
Darwan permissions
across 16 categories
4
Public surfaces
www, app, webmail, mail
6
Provider adapters
Postal, SMTP, Arena, SMPP, SIGTRAN, WhatsApp
build . platform 270617cbus . rabbitmq 4.2

Illustrative dispatch shape from the Messaging service. The same envelope fans out to Voice, SMS, Email, Stalwart, and WhatsApp Cloud without channel-specific glue in the caller.

01 / What is BitsPath?

definition . for engineers and AI engines

BitsPath is KaritKarma's multi-tenant unified communications platform: one product, one auth model, every channel a business actually sends on.

The platform is nineteen .NET 10 projects: fourteen services (Tenancy, Messaging, Push, Voice facade, CRM, Billing, Campaigns, Journeys, Conversations, Analytics, Contact Center, Knowledge Base, Community, Developer), two gateways (the YARP ApiGateway and the EventsGateway webhook ingest), and three shared libraries, talking over MassTransit on RabbitMQ.

Voice and SMS run on a separate pure-Rust runtime: four crates implement a carrier-grade SIP and media stack, five more implement SCTP, M3UA, SCCP, TCAP, and MAP for direct SIGTRAN/SS7 interconnect.

The mailbox engine is Stalwart, embedded inside the BitsPath product boundary; the webmail is a custom Next.js JMAP client that ships search operators, schedule send, vacation autoresponder, and a Gmail-clean theme.

Authentication is exclusively Wenme OAuth 2.1 with mandatory PKCE, validated against the EdDSA + RS256 JWKS.

Authorization is exclusively Darwan: 152 seeded permission strings across 16 categories, enforced both on .NET (279 [RequirePermission] attributes across 45 controllers) and Rust (require_permission() on the Voice API's 225 endpoints).

Carrier and SMTP credentials are bring-your-own, held in a per-tenant vault with circuit-breaker failover between providers.

02 / Channel fabric

Every transport your business pays a different vendor for. Built into one product.

Channel adapters are first-class. The same Messaging service envelope fans out to Voice, SMS over Arena, SMPP, or SIGTRAN, Postal or generic SMTP, Stalwart IMAP/JMAP, and Meta WhatsApp Cloud. Bring your own provider keys per tenant; delivery rides your own contracts.

Provider model
  • Per-tenant credential vault, never global.
  • Circuit-breaker failover: postal to smtp; arena to sigtran to smpp.
  • Delivery receipts converge on EventsGateway.
  • M01

    Voice PBX, pure Rust

    Carrier-grade SIP and media in Axum, no FreeSWITCH, no Asterisk.

    Four Rust crates own the voice path: bitspath-sip (parser, transactions, UDP/TCP/TLS/WebSocket), bitspath-pbx (registrar, routing, CDR, IVR, ring groups), bitspath-media (RTP/RTCP/SRTP, G.711/G.722, jitter buffer, conference mixing), bitspath-call (B2BUA, NAT latching, str0m WebRTC). The five-crate SS7 stack powers SMS.

    BYO SIP trunk or run on your own DID inventory.
    voice.bitspath.com
  • M02

    SMS over SMPP + SIGTRAN

    Direct operator interconnect, not just aggregator API resale.

    Five SS7 crates ship in-tree: bitspath-sctp (async transport), bitspath-m3ua (ASP state machine), bitspath-sccp (Global Title translation), bitspath-tcap (transaction manager), bitspath-map (sendRoutingInfoForSM, mt-ForwardSM, mo-ForwardSM). The bitspath-smsgw binary exposes a priority queue REST API.

    BYO Arena aggregator key, your own SMPP bind, or a SIGTRAN interconnect.
    Direct SIGTRAN/SS7 interconnect
  • M03

    Transactional and marketing email

    MJML drag-and-drop editor, Postal-relayed, full engagement telemetry.

    GrapeJS + grapesjs-mjml composes templates client-side, MJML renders server-side. Postal stays the outbound MTA so reputation and warmup survive. Delivery webhooks feed the unified contact timeline through EventsGateway.

    BYO Postal server or any SMTP relay of your own.
    Postal + generic SMTP adapters in code
  • M04

    Stalwart webmail, per-tenant business email

    Custom Next.js JMAP client over a Rust mailbox engine.

    Stalwart provides SMTP, IMAP, JMAP, CalDAV, CardDAV, and S/MIME inside the BitsPath product boundary (same repo, same release train). The webmail ships Gmail-style search operators, bulk select, star/flag, mobile swipe gestures, schedule send + 3s undo (commit-on-unmount), vacation autoresponder, and an M365-style app switcher.

    Per-tenant domain MX -> mail.bitspath.com; app-password protocol for IMAP clients.
    webmail.bitspath.com, Stalwart JMAP backend
  • M05

    WhatsApp Cloud API

    Official Meta Cloud API, template management, session windows.

    Template review and storage, opt-in capture, 24-hour session-window tracking, media + interactive button support. The Conversations service surfaces inbound threads on the agent inbox with SignalR realtime push.

    BYO Meta Business account + WABA phone number.
    Meta Cloud API, WhatsApp Business Account
  • M06

    Push: device registry today, dispatch next

    Per-tenant FCM and APNs credential vault plus a device-token registry.

    The Push service ships a device-token registry and per-tenant FCM and APNs credential storage. The send pipeline is not yet wired to FCM or APNs, and BitsPath does not market push delivery until it is. Register devices and store credentials now; dispatch lands without an API change.

    BYO FCM project + APNs credentials, stored per tenant.
    Registry + credential vault in code

03 / Service map

Sixteen deployable services. One YARP gateway. One Wenme + Darwan trust path.

Each service owns its EF Core context and Postgres schema. MassTransit on RabbitMQ 4.2 handles async fan-out. The Voice runtime is a separate Rust process, but speaks the same Wenme JWT (EdDSA + RS256) and the same 64 seeded pbx.* Darwan permissions as the .NET ContactCenter service.

Dispatch fabric + gateways
SVC.02

Messaging

:5002

The send fabric. Six provider adapters: Postal, generic SMTP, Arena, SMPP, SIGTRAN gateway, WhatsApp Cloud, behind a circuit-breaker resolver. MassTransit over RabbitMQ for async + retry.

Six provider adapters
PostalSMTPArenaSMPPSIGTRANWhatsApp Cloud
SVC.00

ApiGateway / YARP

:5000

YARP reverse proxy. /api/* fans out to every service. A CookieToBearer middleware converts the Wenme session cookie into an Authorization: Bearer header for downstream calls.

SVC.03

EventsGateway

:5003

Webhook ingest for delivery reports, billing events, and Darwan cache invalidation. Verifies HMAC signatures, idempotent by event id, drops noisy retries.

Engagement engines
SVC.04

CRM

:5004

Unified contact store. Custom fields, consent flags, segments, lists, import. Every channel event lands on the contact timeline. 6 crm.* permissions.

SVC.06

Campaigns

:5006

Multi-channel broadcast engine with background workers. A/B testing, send-time optimization, throttled delivery against per-provider rate caps.

SVC.07

Journeys

:5294

Visual @xyflow/react builder. Branching, delays, wait-for-event, channel switches. One orchestrator runs all six channels.

SVC.08

Conversations

:5292

Omnichannel agent inbox over SignalR. Threads merge inbound across Email, SMS, WhatsApp. No per-agent pricing model.

SVC.09

Analytics

:5204

Delivery, engagement, funnel reports. Recharts 3.7 in the portal, raw event API for downstream BI exports.

Voice plane . Rust + .NET

Voice (Rust)

SVC.15 . :8080

Pure-Rust Axum API + SIP server on host network. 64 seeded pbx.* permissions enforced via require_permission() on every handler. WebRTC bridge via str0m, TURN via coturn.

ContactCenter

SVC.10 . :5210

Agent desktop on the Voice PBX. Queues, transfers, supervisor barge, whisper, listen. Reuses the same 64 seeded pbx.* permission strings Voice enforces.

Tenant + platform ops
SVC.01

Tenancy

Tenants, users, roles, onboarding. Syncs the Wenme JWT subject to the internal user row on first login. The seed account links by email, then pins on the Wenme sub on next sign-in.

:5001
SVC.05

Billing

Usage metering, credit packs, plan tiers. Per-tenant ledger with daily roll-ups.

:5005
SVC.11

KnowledgeBase

Self-service help center. Article CRUD, search, public surface. 4 knowledge.* permissions.

:5215
SVC.12

Community

Community forum module. Threads, replies, moderation. 4 community.* permissions.

:5220
SVC.13

Developer

Webhooks with delivery tracking, API keys, API logs, sandboxed extension engine.

:5225
SVC.14

Push

Device-token registry and per-tenant FCM/APNs credential vault. The dispatch path is not yet wired to FCM/APNs; registry and credential storage are real today.

registry

04 / Webmail . Stalwart

Business email for tenants who don't want to be a Google customer.

The mailbox engine is Stalwart, a single Rust binary that handles SMTP, IMAP, JMAP, CalDAV, CardDAV, WebDAV, integrated spam filtering, S/MIME, and OpenPGP at rest. It lives inside the BitsPath product boundary, the way FreeRADIUS lives inside ISPChamp. Postal stays the outbound relay so a tenant's mailbox outbound never poisons the transactional API reputation envelope.

Surface map
  • bitspath.com . marketing + product site
  • app.bitspath.com . tenant portal + admin
  • webmail.bitspath.com . JMAP webmail (Next.js 16.2)
  • mail.bitspath.com . Stalwart SMTP/IMAP/JMAP/CalDAV
  • voice.bitspath.com . Rust PBX, SIP on host network

Webmail with Gmail-grade UX

Search operators (from:, subject:, has:attachment, older_than:), bulk select with vim navigation, star and flag, mobile swipe gestures, schedule send, 3-second undo-send with commit-on-unmount (no silent drops), vacation autoresponder with iTIP REPLY on calendar RSVP. Cookie-backed preferences, theme registry, M365-style app switcher.

Auth that respects IMAP reality

Webmail uses Wenme OAuth 2.1 directly. IMAP and SMTP clients cannot speak OAuth, so BitsPath issues per-device app passwords (the Google, Apple, and Proton pattern). Stalwart validates against Wenme's public app-password verification endpoint, never an admin API.

Per-tenant S3-compatible storage

Stalwart's S3 backend writes to S3-compatible object storage, one bucket per tenant. Encryption uses Stalwart's built-in S/MIME and OpenPGP support. Outbound mailbox traffic relays through Postal so reputation routes through warmed IPs.

Multi-tenant by domain, white-labellable

Customer domain MX records point at mail.bitspath.com. Resellers can CNAME webmail.<reseller>.com to the BitsPath webmail. One Stalwart instance handles N domains; one Next.js webmail serves N reseller skins.

Webmail commit log . last session
270617c..59111a6
feat(webmail): /search route with Gmail-style operators (P1.1)
feat(webmail): bulk select + star/flag + mobile swipe gestures
feat(webmail): schedule send + 3s undo-send window
feat(webmail): vacation polish + iTIP REPLY on RSVP
feat(webmail): Gmail-clean light theme as default + theme registry
feat(webmail): M365 app switcher + Wenme avatar dropdown
feat(webmail): Gmail-style settings deep-dive (general/account/identities)
fix(webmail): undo-send commits on unmount, not silently drops

05 / Voice + SIGTRAN

A PBX KaritKarma wrote. Not an Asterisk fork dressed up as a product.

Four Rust crates own the voice path. Five more own SS7 for direct operator SMS. The PBX runs as a host-network SIP server alongside the API container, with WebRTC bridged via str0m (ICE and DTLS-SRTP implemented) and TURN served by coturn. The same Wenme JWT and the same seeded pbx.* permissions enforce every endpoint.

225
Voice REST endpoints
10
Rust crates + API server
64
seeded pbx.* permissions
Edge SCTP
M3UA/SCCP/TCAP/MAP

120K+ lines of Rust telephony

Four pure-Rust crates own the voice path: bitspath-sip, bitspath-pbx, bitspath-media, bitspath-call. No C dependencies in the call leg, no FreeSWITCH, no Asterisk. FreeSWITCH has been fully removed.

Full SIGTRAN/SS7 stack

bitspath-sctp + m3ua + sccp + tcap + map crates power the bitspath-smsgw binary for direct operator SMS interconnect, not just aggregator API resale.

64 seeded pbx.* permissions

Voice (Rust) and ContactCenter (.NET) share the same seeded pbx.* permission strings. require_permission() runs on the Voice API's 225 REST endpoints with the unified darwan_tenant_id forwarded from Portal.

WebRTC via str0m + coturn

Browser legs land on a B2BUA that bridges WebRTC to SIP with ICE and DTLS-SRTP implemented, without transcoding G.711. The media bridge runs hot-path on the same Rust process.

Crate index
bitspath-sip~12,100 lines . parser, transactions, UDP/TCP/TLS/WebSocket
bitspath-pbx~23,100 lines . registrar, routing, CDR, IVR, ring groups
bitspath-media~13,700 lines . RTP/RTCP/SRTP, G.711/G.722, jitter, conference
bitspath-call~23,600 lines . B2BUA, NAT latching, str0m WebRTC
bitspath-sctpasync SCTP transport for the SIGTRAN stack
bitspath-m3uaRFC 4666 ASP state machine, ASPUP/ASPAC handshake
bitspath-sccpGlobal Title translation, SSN routing
bitspath-tcaptransaction manager, BER encoding, Begin/End/Continue
bitspath-map3GPP TS 29.002 SMS subset: SRI-SM, MT-FSM, MO-FSM
bitspath-smsgwstandalone SMS gateway binary, HTTP submit + callbacks

06 / How BitsPath compares

Twilio. SendGrid. Postmark. WhatsApp BSPs. Google Workspace. One platform replaces the whole spreadsheet.

Every row below is sourced from the BitsPath codebase at commit 270617c and from the live deployment at bitspath.com, webmail.bitspath.com, mail.bitspath.com, and voice.bitspath.com.

Scroll for full table

CapabilityBitsPathTwilioSendGridWorkspace
Voice PBX in the same productPure Rust PBXYes (proprietary)
Direct SS7 / SMPP interconnectSIGTRAN crates in-tree
Per-tenant business email + webmailStalwart-backed JMAP webmailHosted only
BYO provider credentials, per tenant
Omnichannel agent inbox, no per-agent feeFlex, per-agent
Single auth + RBAC (Wenme + Darwan)OAuth 2.1 + 152 permsVendor IAMVendor IAMGoogle IAM
BDT pricing, contracts under Bangladesh lawUS/EU regions
Self-host or sovereign deployDocker Compose appliance

07 / How to onboard a tenant

Four calls. First message under the same hour.

The onboarding flow is documented as a HowTo schema so AI engines and voice assistants can quote it verbatim. Every step maps to a real endpoint in the BitsPath gateway.

  1. 01

    Provision the tenant

    POST /api/tenancy/tenants with company metadata. Tenancy syncs a Wenme tenant, creates a Darwan tenant id, and seeds the default roles plus the 152 baseline permissions across 16 categories.

  2. 02

    Wire your sender identities

    Add Postal or SMTP credentials, an Arena aggregator key, an SMPP bind or SIGTRAN interconnect, and a Meta WhatsApp Business phone number. Per-tenant credential vault, never global. FCM and APNs credentials can be stored ahead of push dispatch.

  3. 03

    Verify the mailbox domain (optional)

    If you want per-tenant business email, point MX records at mail.bitspath.com, add the DKIM and SPF rows BitsPath generates, and provision mailboxes from the portal. Stalwart picks them up live.

  4. 04

    Send the first message

    Trigger a single send via the API or compose a Journey in the visual builder. The Messaging service routes through the chosen provider, captures the delivery webhook on EventsGateway, and lands the event on the CRM contact timeline within seconds.

08 / Stack

What BitsPath is actually built on.

Platform runtime
.NET 10, ASP.NET Core, EF Core 10.0.5
Voice runtime
Rust 2024 edition, Axum 0.8, SQLx
Frontend
Next.js 16.2, React 19.2, Tailwind CSS 4, shadcn/ui
Realtime
SignalR (Conversations) + JMAP (Webmail)
Message bus
MassTransit over RabbitMQ 4.2
Data
PostgreSQL 18, Redis 8.6, S3-compatible object storage
Mailbox engine
Stalwart (Rust): SMTP / IMAP / JMAP / CalDAV / S/MIME
Telephony
SIP/RTP/SRTP/WebRTC + SCTP/M3UA/SCCP/TCAP/MAP

09 / Frequently asked

The questions enterprise buyers actually ask.

Every answer is mirrored into the FAQPage JSON-LD on this page, so AI answer engines can quote it as a single source of truth.

  • What is BitsPath?

    BitsPath is KaritKarma's multi-tenant unified communications platform. It is 19 .NET 10 projects (14 services, 2 gateways, 3 shared libraries) plus a pure-Rust voice and SS7 stack, plus a Stalwart-backed JMAP webmail, all wired into one product. The platform delivers Voice (carrier-grade PBX), SMS (Arena aggregator, direct SMPP, or SIGTRAN), Email (transactional and marketing via Postal or any SMTP relay), per-tenant business email (Stalwart SMTP/IMAP/JMAP/CalDAV), and WhatsApp Business Cloud API, with CRM, Campaigns, Journeys, Conversations inbox, Analytics, Contact Center, Knowledge Base, and Community sitting on top. A push device registry and credential vault ship ahead of push dispatch. Authentication is Wenme OAuth 2.1 with mandatory PKCE; authorization is 152 Darwan permissions across 16 categories.

  • How is BitsPath different from Twilio?

    BitsPath ships its own carrier-grade PBX written in pure Rust (no FreeSWITCH, no Asterisk) and its own SIGTRAN/SS7 stack so SMS can ride a direct operator interconnect, not just aggregator API resale. The application layer (CRM, Campaigns, Journeys, Conversations) is included, not per-agent priced. Customers bring their own provider credentials, so delivery rides their own carrier and relay contracts rather than a resold rate card. Pricing is in BDT with contracts under Bangladesh law, which Twilio does not offer.

  • Does BitsPath support WhatsApp Business Cloud API?

    Yes. BitsPath integrates the official Meta Cloud API for WhatsApp Business. Tenants connect their own Meta Business account and WABA phone number; BitsPath handles template review and storage, opt-in capture, 24-hour session-window tracking, media payloads, interactive buttons, and inbound message ingest. Inbound conversations land on the omnichannel agent inbox with SignalR realtime push.

  • Does the webmail support IMAP and SMTP clients like Outlook and Apple Mail?

    Yes. The mailbox engine is Stalwart (open-source Rust, single binary handling SMTP, IMAP, JMAP, CalDAV, CardDAV, WebDAV, S/MIME, and OpenPGP at rest). Modern web sessions use the JMAP webmail with Wenme OAuth 2.1 directly. Legacy IMAP and SMTP clients use per-device app passwords (the same pattern Google, Apple, and Proton ship). App passwords are scoped to a single mailbox, revocable, and validated through Wenme's public verification endpoint, never a Wenme admin API.

  • Can BitsPath replace FreeSWITCH or Asterisk?

    Yes. The Voice service is a complete carrier-grade PBX built in pure Rust across four crates: bitspath-sip (parser, transactions, UDP/TCP/TLS/WebSocket), bitspath-pbx (registrar, routing, CDR, IVR, ring groups), bitspath-media (RTP/RTCP/SRTP, G.711/G.722, jitter buffer, conference mixing), and bitspath-call (B2BUA, NAT latching, str0m WebRTC). FreeSWITCH has been fully removed from the product, there are no C dependencies in the call leg, no GPL licensing concerns, and seeded pbx.* permission strings are enforced via Darwan on every Voice API endpoint.

  • What happens to my existing carrier and SMTP relationships when I move to BitsPath?

    They survive. BitsPath's bring-your-own-provider model means existing SIP trunks, SMPP binds and SIGTRAN interconnects, SMTP credentials (Postal or any SMTP relay of your own), Arena aggregator keys, and your Meta WhatsApp Business account all keep working, stored in a per-tenant credential vault with circuit-breaker failover between providers. BitsPath becomes the orchestration, CRM, and inbox layer on top. IP reputation and warmup history stay with the underlying relay, and delivery rides your own provider contracts.

10 / Get started

Replace the spreadsheet.
Move your channels to one wire.

Wire your channels into one product. Bring your carrier, your SMTP, your WABA number. BitsPath becomes the CRM, the campaign engine, the journey builder, the agent inbox, the webmail, and the PBX. Your provider contracts stay yours.

Open the platformRequest a demo

A personalized walkthrough of BitsPath with one of our specialists. No commitment required.

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