FusionSIP vs Flex Call Manager
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
FusionSIP
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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.
Flex Call Manager
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++ 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
Verdict
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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
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.
| Parameter | FusionSIP | Flex Call Manager |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 2 weeks — better | Monthly |
| Ads | No | No |
| In-app purchases | No | No |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod, Mac — better |
| Requires iOS | 15.0 | 15.0 |
| Further details — not scored | ||
| Size | 11 MB | 11 MB |
| Age rating | 4+ | 4+ |
| Developer | EDNT GmbH | Gamma Communications GmbH |
In-app purchases
FusionSIP
No in-app purchases
Flex Call Manager
No in-app purchases









