Comparison

FusionSIP vs Flex Call Manager

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

FusionSIP

Features
Read full description

FusionSIP: The Mobile SIP Client for FusionPBX FusionSIP is the ideal mobile solution for users of the open-source FusionPBX phone system. Simple, flexible, and powerful - FusionSIP keeps you perfectly connected on the go. Highlights: Easy Setup: Configure via QR code or manual SIP data entry. Seamless Integration: Direct connection to FusionPBX via the EDNT Softphone API, which provides all necessary data. Cutting-Edge Technology: Supports push notifications, IPv4, and IPv6. Powerful Features: Extension selection Hold, call switching, and call forwarding (unattended & attended) Conference calling BLF and status display for colleagues Public and private phonebooks (local and server-based) Server-based call history, notes, and scheduling (private & public) Integrated chat (requires XMPP server) FusionPBX voicemail management Full fax support (send & receive) Manage call forwarding and block lists Customizable codecs, volume control, and Bluetooth support User-friendly design with Light & Dark Mode For Businesses & Offices: FusionSIP is also available in a desktop version, including interfaces to ERP and CRM systems. On request, the app can be custom-branded and tailored to your needs. Who is FusionSIP for? FusionSIP is specifically designed for businesses that use FusionPBX, providing a reliable, user-friendly solution for efficient communication—anytime, anywhere. For Resellers: Upon request, the softphone can be branded, customized, and discounted. Download now and experience the full power of FusionPBX in the palm of your hand! Important Note: The FusionSIP soft client can only be used in combination with the EDNT SoftPhone API and FusionPBX. For a generic softphone solution, EDNT offers the Smart-SIP-Phone, which works as a SIP client immediately with any PBX or phone system.

About

Flex Call Manager

Read full description

++ Achtung: Die Flex Call Manager App funktioniert nur in Verbindung mit einem aktiven Account ++ Flex Call Manager ist ein modernes Kommunikationssystem von Gamma. Holen Sie sich Ihre Telefonanlage auf Ihr Smartphone.  Über diese App verwenden Sie Ihr Smartphone als mobile Nebenstelle Ihrer virtuellen Telefonanlage.  Empfangen und starten Sie weltweit Anrufe unter Ihrer Festnetznummer und telefonieren Sie kostengünstig auch unterwegs. Nutzen Sie die Funktionen Ihrer Telefonanlage sowie alle Features der Gamma FlexPBX.

Screenshots

FusionSIP4 screens
Flex Call Manager4 screens

Verdict

The call

FusionSIP and Flex Call Manager are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

FusionSIP ships an update every 2 weeks, Flex Call Manager monthly. The most recent releases landed on September 15, 2026 and December 12, 2025 respectively.

ScorecardNo meaningful differences
FusionSIP versus Flex Call Manager: the parameters behind the verdict, then further details
ParameterFusionSIPFlex Call Manager
PriceFreeFree
Update frequencyEvery 2 weeks — betterMonthly
AdsNoNo
In-app purchasesNoNo
DevicesiPhone, iPad, iPodiPhone, iPad, iPod, Mac — better
Requires iOS15.015.0
Further details — not scored
Size11 MB11 MB
Age rating4+4+
DeveloperEDNT GmbHGamma Communications GmbH

In-app purchases

None

FusionSIP

No in-app purchases

None

Flex Call Manager

No in-app purchases

Questions

Is FusionSIP free?
FusionSIP is free to download, with no in-app purchases.
Is Flex Call Manager free?
Flex Call Manager is free to download, with no in-app purchases.
Do FusionSIP or Flex Call Manager have ads?
Neither FusionSIP nor Flex Call Manager shows ads.
Which is updated more often, FusionSIP or Flex Call Manager?
FusionSIP ships an update every 2 weeks, and Flex Call Manager monthly. Most recently, FusionSIP was updated on September 15, 2026 and Flex Call Manager on December 12, 2025.

Other comparisons