Build a white label softphone app
Create a custom white-label softphone with Cloud Softphone.
- No devs needed
- Native desktop apps
- 100+ premium features
The history of VoIP is full of clever hacks. Solutions that started as stopgaps, even kludges, often ended up becoming the standard way of doing things. One of the best examples is push notifications for incoming calls on softphones.
What began as a workaround has become the only accepted method on mobile platforms. And Acrobits was there from the start.
The VoIP world has always been shaped by ingenuity. When something didn’t work, developers and engineers hacked their way around it, and often those hacks hardened into industry standards. Here are some of the most influential:
Early VoIP calls often failed when devices sat behind NAT or firewalls. The first workaround was to “ask a server” (STUN) what the device’s public IP looked like. That hack grew into TURN (relay servers) and eventually ICE, which is now the standardized connectivity method used by both SIP and WebRTC.
To stay reachable behind NAT, SIP clients used to send improvised REGISTER refreshes or TCP keep-alives. Over time, this became formalized in SIP Outbound, which standardizes multiple persistent flows and keep-alive mechanisms – turning messy hacks into predictable behavior.
Browsers don’t support raw SIP over UDP/TCP. The workaround was to tunnel SIP messages through WebSockets. This hack gained traction, and today SIP over WebSockets is the recognized way to bring SIP into WebRTC-based web applications.
In the early days, encrypting media with SRTP often required clumsy pre-shared keys or proprietary key exchanges. The workaround was to reuse TLS handshakes over datagrams – DTLS-SRTP. It became not only a standard but a mandatory media security model for WebRTC.
Narrowband codecs (G.711, GSM, SILK) worked in some environments, wideband (CELT, AMR-WB) in others. Developers hacked around by switching codecs on the fly. The solution was to merge the best of SILK (speech) and CELT (music) into Opus – now the universal audio codec of WebRTC. Supported in softphones by Acrobits from the very beginning.
At first, SBCs were deployed as “patch boxes” to normalize SIP signaling, fix NAT issues, and enforce security policies. The industry soon realized that they solved too many problems to be optional. Today, SBCs are not a hack but a core architectural element in any serious VoIP network.
When Apple killed background SIP, Acrobits built push servers to bridge SIP INVITEs into Apple Push Notifications. That workaround eventually became formalized with PushKit/CallKit, and is now the only way to deliver VoIP calls on iOS.
Push for VoIP is one of the clearest examples of a hack that became a standard. What started as a survival tactic turned into the only accepted way to deliver mobile VoIP.
In 2010, iOS 4 changed how background processes worked. Apps could no longer run SIP stacks in the background to listen for INVITE requests. That meant if your softphone wasn’t in the foreground, you simply missed calls. For many providers, it looked like iOS VoIP was dead.
To get around this, early innovators, including Acrobits, designed a push server model. Instead of the app itself staying awake, the SIP server sent call requests to a middle service. That service converted the incoming INVITE into an Apple Push Notification, which woke the app. The app then quickly re-registered to SIP and established the call.
Acrobits was one of the first to roll out a production-ready push infrastructure. Because their Cloud Softphone platform was white-label, carriers, ITSPs, and PBX providers around the world could adopt the workaround without building push systems themselves. This helped normalize the architecture long before Apple offered official support.
In 2015-2016, Apple introduced PushKit (for VoIP push) and CallKit (for integrating calls with the iOS dialer UI). These frameworks effectively mandated the push approach as the only compliant way to handle incoming calls. For Acrobits’ customers, the transition was smooth – they were already running on a mature push system.
What started as a hack to keep VoIP alive on iOS has become a mandatory design choice. Today, no VoIP app can work on iOS without push, and even Android has moved in the same direction with power management features like Doze and Firebase Cloud Messaging.
The evolution of push notifications for VoIP shows a familiar pattern in telecom innovation:
Developers invent quick fixes to keep systems alive when platforms or networks impose new limits.
Those fixes spread fast because they are the only way to keep services working.
Eventually, the workaround is recognized, formalized, and baked into platform requirements or RFCs.
It started as a hack to bypass iOS background restrictions, became the survival mechanism that kept iOS VoIP alive, and then turned into the only approved method for call delivery on mobile.
Acrobits’ role in this story was critical – by pioneering a production-ready push infrastructure early, we enabled carriers, ITSPs, and PBX admins worldwide to keep their VoIP services viable on iOS without reinventing the wheel. That groundwork shaped how the entire industry delivers mobile VoIP today.
At Acrobits, we perceive hacks not as ugly shortcuts but as the first step toward progress. The key is adopting them early, refining them, and being ready when they evolve into tomorrow’s standards.
Create a custom white-label softphone with Cloud Softphone.
Android’s greatest strength, its openness and vast device diversity, has also created its most persistent challenge for developers: fragmentation. While Apple’s iOS universe is carefully curated, Android is free to roam across more than 20,000 device types. This means every launch is met by confronting a maze of device-specific quirks, platform evolutions, and new compliance […]
The Customer Acquisition Challenge In today’s digital marketplace, ESIM providers face an increasingly difficult challenge when it comes to customer acquisition. As the industry matures, competition for keywords in digital advertising has intensified dramatically, resulting in higher customer acquisition costs across the board. Major players and emerging startups alike find themselves trapped in bidding wars […]
With more businesses relying on softphones for internal and external communication, the security of your VoIP system has never been more critical. As VoIP adoption grows, so do threats like VoIP hacks, toll fraud, and denial-of-service attacks, putting your business communications and data at risk. To stay protected, it’s essential to implement tools like SBCs […]
Communication is the heart of any business, including working with people who aren’t in the office or even the same region. Whether this means remote workers, suppliers, clients, or customers — your business relies on phone systems that work without issue. Two types of softswitches are at the heart of reliable communication but often go […]
