Flexisip

OPEN SRC

Complete, modular and scalable SIP server, includes a push gateway, to deliver SIP incoming calls or text messages on mobile device platforms where push notifications are required to receive information when the app is not active in the foreground

► Mobile app developers requiring SIP push notifications

VG SCORE

6.5

VIEW ALTERNATIVES

Product Details

PricingOpen Source

API✅ REST

Learning CurveSteep

Integrations12 available

■ INTELLIGENCE BRIEFING — Weekly tool drops. No spam.

PROS & CONS

STRENGTHS

Strong foundation from the established Linphone project ecosystem.
No licensing costs, being fully open-source under GPLv3.
Solves the critical mobile push notification problem for SIP reliably.

WEAKNESSES

−Requires significant technical expertise to deploy and configure properly.
−Documentation can be sparse, leaning on community knowledge.

KEY FEATURES

Modular Architecture

Components can be enabled/disabled for custom deployments.

Scalable Design

Built to handle growth from small to large user bases.

Open Source & Free

Released under GNU GPLv3 with an active community.

Integrated Push Gateway

Delivers calls/messages to mobile apps via platform push services.

WHO IS Flexisip BEST FOR?

Telecom service providers and carriers

They can use Flexisip to build scalable, standards-compliant VoIP and messaging services with reliable mobile push notifications.

INTEGRATIONS

MySQL/PostgreSQLSIP proxies and registrarsdatabase backends (e.g., Redis)RTP proxiesRedisRTP/RTCP media serversauthentication servers (e.g., via RADIUS)SIP clientsHTTP-based servicesMobile push notification services (Apple APNs, Google FCM)log and monitoring systemsLinphone