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Voice PBX: pure Rust SIP stack

An enterprise PBX, rebuilt from the SIP parser up.

A complete PBX built from scratch in Rust: SIP parser, B2BUA, RTP relay, conference mixer. 20,000 lines replacing 2 million. No FreeSWITCH, no Asterisk.

  • Memory-safe by construction
  • Native multi-tenant (RLS)
  • REST API for everything
console.bitspath.com/voice
ext 204+8801•• support line04:12Talking
ext 118conference: standup12:47Mixing
trunk-02IVR: main menu00:19DTMF
Queue: support2 agents ready
12
Active calls
0:42
Avg wait
On
SRTP
20K
Lines of Rust
4
Purpose-built crates
255+
REST endpoints
35+
RLS tables
12 core modules

Everything a modern PBX needs

All managed through the Portal UI and the REST API. No config files to hand-edit, no dialplan scripting language to learn.

01

Extensions

CRUD, bulk import/export, provisioning profiles for SIP phones and softphones.

02

Ring Groups

4 hunt strategies: simultaneous, sequential, round-robin, weighted routing.

03

IVR Menus

Multi-level menus, DTMF routing, time-of-day conditions, failover destinations.

04

Call Queues

Agent management, configurable hold music, max wait time, queue callbacks.

05

Voicemail

Custom greetings, message management, email notifications with audio attachments.

06

Conferences

PIN-protected rooms, moderator controls, mute/kick, participant limits.

07

Call Flows

Visual drag-and-drop flow builder with conditions, branches, and sub-flows.

08

Routes

Inbound/outbound routing rules, time conditions, regex pattern matching, trunks.

09

CDR

Call detail records with advanced filters, date ranges, and CSV export.

10

Recordings

On-demand and automatic call recording, streaming playback, bulk download.

11

Music on Hold

Multiple categories, track management, per-queue and per-tenant playlists.

12

Active Calls

Real-time call monitoring dashboard: listen, whisper, barge, hangup, transfer.

Architecture, not marketing

How BitsPath Voice compares

Side-by-side with the incumbents on the things that decide operability: codebase, tenancy, API surface, and memory safety.

FeatureBitsPath VoiceFreeSWITCHAsterisk3CX
LanguageRustCCC++ (proprietary)
Codebase Size~20,000 lines2,000,000+ lines1,000,000+ linesProprietary
LicensePlatform subscriptionMPL 1.1 / CommercialGPL v2 / CommercialPer-user license
SIP Stackbitspath-sip (custom)mod_sofia (oSIP)chan_pjsip (PJSIP)Proprietary
Media Enginebitspath-media (SRTP, G.711/G.722)mod_dptoolsBuilt-inBuilt-in
Web Admin UIIncluded (Portal)FusionPBX (separate)FreePBX (separate)Included
Multi-TenantNative RLS (35+ tables)Domain-based (add-on)Not nativeLimited
REST API255+ endpointsESL + mod_xml_curlAMI / ARIProprietary API
WebRTCWebSocket transportmod_vertoBuilt-in (limited)Built-in
Memory SafetyGuaranteed (Rust)Manual (C)Manual (C)Unknown
Four purpose-built crates

No forks, no wrappers, no FFI bindings

Every line is ours, which is why the whole stack fits in four crates you can actually audit.

bitspath-sip~3,500 loc

SIP parser, transactions, transports (UDP/TCP/TLS/WebSocket). RFC 3261 compliant message parsing with zero-copy headers.

bitspath-pbx~6,650 loc

Registrar, routing engine, CDR, call forwarding, ring groups, IVR menus, voicemail, and conference bridge orchestration.

bitspath-media~3,000 loc

RTP/RTCP/SRTP processing, G.711 and G.722 codecs, adaptive jitter buffer, conference mixing with N-1 audio streams.

bitspath-call~7,000 loc

B2BUA call engine, call state machine, RTP relay with NAT latching, reinvite handling, and oRTP-based media relay.

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