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Top 10 SIP & VoIP Calling API & SDK Providers to Build Voice Chat Application

List of Best SIP & VoIP Calling Solutions for iOS & Android Application

Top 10 SIP & VoIP Calling API & SDK Providers to Build Voice Chat Application

Monday March 04, 2019,

9 min Read


“The size of European VoIP market is expected to rise about 14 billion U.S. dollars”

Before getting into the actual SIP and VoIP providers in the market, let's make clear about the purpose and definition of SIP Trunking to replace your traditional business phone lines.

Everything about SIP Trunking

Session Initiation Protocol is equivalent traditional business phone calls where the communication initiates virtually. A SIP trunk is a set of virtual connections to the Public Switched Telephone Network (PSTN) with the use of internet connection. A trunk is a shared communication path for the entire telephone network users. On the other hand, SIP protocol enables VoIP services to progress.

The Working Principle of SIP Trunking

The SIP Trunking system delivers a unified communication service to your telephone over existing IP networks. The SIP technology replaces the traditional telephone lines and VoIP users can make it directly to any phone by connecting to PBX system via Internet. 

With a compatible SIP trunk, a virtual call is established from the SIP phone (VoIP) to other connected devices through the PSTN network. 

SIP Trunking

SIP Trunking (Image Credit: Nextiva Blog)

To establish SIP Trunking connectivity, the following set up includes,

  • A stable internet connection
  • SIP-compatible PBX,
  • VoIP devices especially VoIP phones,
  • Unified network connection with devices.

The importance of SIP/VoIP connectivity is a need for an hour for most of the businesses to establish a strong communication network between customers and organizations. The purpose of SIP voice call has a huge impact for Fortune 500 and large businesses to maintain local and overseas business. 

Benefits of SIP Trunking Services for Fortune 500 & Large Businesses

Lower Maintenance Cost

With few hardware setups, an integrated SIP trunking could replace your existing traditional phone call system. Additional call points or devices can be added without use of new hardware. Scaling new connectivity is made simple with SIP call APIs.

Cheaper than PRI Trunks

The SIP trunking is over 25% cheaper than the PRI (Primary Rate Interface) since SIP offers low calling rates and free voice calls between any offices on the same VoIP system. 

Inherent Flexibility

SIP offers the flexibility to add or subtract users and as much as phone lines required by any business. The entire connectivity can be handled through a dedicated web portal by customizing the phone system based on the needs. 

Call Anywhere Any device

If your entire business is related to overseas calling, SIP offers call connectivity from any device, mobile, PBX connected PCs and many more. Make uninterrupted voice calls with the help of SIP interconnects.

Prepared For Any Situations

The analog system can be disrupted during any bad weather, but SIP trunks can help to prioritize call system, routing and rerouting of calls to different networks, devices and phones.

Take Phone System Anywhere

With an SIP interconnected phone system or on smartphone, you can make business calls anywhere you travel by connecting to a temporary SIP network through the internet.

Factors In Choosing the Right SIP Trunking Solution for Business


This is the big concern for any business seeking for an enterprise business communication, so understanding the core security features of any SIP and VoIP solution provider before choosing one. 


Ability to scale unlimited connectivity is the prime feature of any SIP trunking provider, thus choosing an enterprise provider can scale your VoIP call connectivity across global offices.


Since not all the businesses can afford such a high price for each call, large and small businesses can rely on enterprise SIP trunk providers where the quality and pricing is dependent on the pay as you use. 

Self Hosted Network

Choosing a self hosted SIP phone solution can easily cut the middleman where some of the providers are hosted on another providers’ network. 

To make a voice call app you would prefer the best VoIP & SDK providers in the market, this, in turn, enhances your sales value and yields you a better ROI. In order to reduce the burden of discovering the ideal VoIP API provider for Android, iOS, we’ve come up with some top 10 VoIP & SIP calling providers to develop a voice call app that performs persistently across devices & platforms.

World’s Top 10 SIP & VoIP Calling API Providers in the Market for Businesses

Contus Fly - A Powerful VoIP API/SDK Provider for Dynamic Voice Experience

One of the leading VoIP API/SDK provider in the market to create a customizable voice chat application in order to make a persistent voice call over the internet. Considered as one of the significant stand-out features is that, it can be customized and compatible with Android, iOS and Web applications. They provide an absolute VoIP API/SDK to integrate or develop your own voice call app with enriched features that adapt to your business purpose. With their unlimited cloud infrastructure and VoIP APIs make, receive and control high-quality calls without the disregard of subscription-based voice call plans. Contus Fly, VoIP functionality as their, provide unlimited voice call possibility with a one-time payment.  

Highlights of Contus Fly SIP Voice Call Solution 

  • App to App calling 
  • App to phone calling
  • SIP Trunking 
  • Call Queueing
  • Callback Service

MirrorFly - An Customizable Voice Calling App Provider

A sublime VoIP API provider for individuals and enterprises to build a voice call application on Android, iOS and Web applications. They have been in the industry for a couple of years in creating evolution in voice call functionality. MirrorFly has proficient in-house developers who can strive to build a voice call app that adapts to any of your business purposes. MirrorFly is in-built with VoIP integration to empower your voice communication over network carrier and enables to make, receive calls across browsers, app and web applications. Their VoIP infrastructure offers voice encoders, low latency DNS to heighten the voice quality even during at low bandwidth.  

Highlights of MirrorFly SIP Trunk Solution

  • App to Phone Calling 
  • App to App Calling 
  • Group Calling 
  • SIP Trunking
  • Call Transfer
  • Call Queueing
  • Call Recording

Twilio - A Programmable Voice API Provider

Twilio is one of the comprehensive voice API providers in the market offering VoIP and SIP protocols to integrate voice calling functionality into your mobile & web applications. With Twilio's VoIP API, you can effortlessly make, receive, & route voice calls from your chat application to any of the carrier networks instantly. They offer latency less call quality and features which enhances the voice call experience of your application.

Highlights of Twilio SIP Calling API Provider

  • SIP Interface 
  • SIP Trunking 
  • SIP Registration 
  • BYOC Trunking
  • Audio Recording 

Linphone - An Ideal VoIP API/SDK Provider in the Market      

A dynamic voice functionality provider assists businesses and individuals to integrate or build voice chat apps on Android, iOS and Web applications. Their VoIP SDK & API for Android, iOS & Web applications enable enterprises to avail voice-based customer service for an effective and instant solution to the queries. Linphone ensures to offer dynamic and clear calls capabilities to different industrial sectors namely healthcare, education, Customer service and so on.

Highlights of Linphone VoIP Calling SDK Provider

  • Voice Interactions
  • Audio & Video Recordings
  • Customize dashboards

Quickblox - An Absolute Calling Toolkit for Developers

One of the major backend infrastructure provider for a chat. Being strong in providing chat APIs, Quickblox also focuses on offering VoIP APIs/SDKs to integrate voice calling feature into web and mobile applications. Quickblox offers ready-to-go modules that assist developers to build an ideal voice call app with features that adapt to any platform and devices.  

Highlights of Quickblox SIP Trunking Solution

  • Remote Media Track
  • VOIP Push Notifications
  • VoIP Calling

Sinch - Experience Smooth Voice Calling With VoIP & SIP integrations   

A real-time VoIP & SIP API provider in the market enables enterprises to create voice calling app on Android, iOS and Web applications. Sinch offer hassle-free integration of high-quality voice API's that supports VoIP, PSTN & SIP. Their cross-platform application delivers a multi-party voice call feature to create engagement and deeper conversation between the brand and customers.    

Highlights of Sinch VoIP Calling API

  • Conference calling
  • Text-to-speech
  • Call recording
  • Cross-platform support

Plivo - A Top-notch Voice API Platform Provider

A scalable voice API provider enables to make, receive, manage and route calls across the devices and platforms instantly. Their open source VoIP SDK functionality offers a diverse set of features such as Conference calls, Voice Survey, Voice notification, Call forwarding and so on. With Plivo’s VoIP API, connect calls from a mobile application to carrier networks with low latency and ensuring high-quality voice calls. Further, they offer Multi-party and audio-conferencing features into your Android, iOS and Web applications.

Highlights of Plivo SIP Calling Solution

  • Conference Call
  • Voice Alerts
  • Voice Survey
  • Call Forwarding 

Vonage - Leading SIP Trunking & Communication API Provider 

Vonage’s SIP trunking makes the connectivity to existing PBX easy for all sorts of businesses. The VoIP and SIP solution provides unlimited capacity with per-second billing rates to scale your business communication globally. Vonage enables you to link your existing PBX infrastructure to cloud at a faster rate with restriction traditional capacity. With elastic SIP trunking, connect instantly to the telephone network to scale up and down on actions from the management.

Highlights of Vonage SIP Trunk Solution

  • Location-based routing
  • SIP Deployment (Beta)
  • Per-second billing

TELNYX - SIP Trunks for Instant & Unlimited Global Scale

Telnyx offers plug and play VoIP setup to establish carrier-grade voice on private and local networks. The VoIP API solution provides redundant multi-cloud infrastructure with 99.999 % uptime and carrier independence just to remove downtime. Telnyx offers high-end security standards such as encryption options for signaling (TLS) and SRTP to secure the entire communication. The VoIP solution provides dedicated debugging and SIP diagnostics to troubleshoot the entire voice calls.

Highlights of TELNYX VoIP API Solution

  • Global Numbers
  • Alerting & Reporting
  • Unparalleled 24x7 Support
  • Fraud Protection & Call Recording

Portsip - Accelerate Voice Capabilities With VoIP SDK

Portsip delivers ready-to-use voice calls over IP and LTE to run the apps on Android, iOS and Web applications. They also provide integratable APIs to make app to app calling through interconnected SIP networks. The VoIP SDK is completely a SIP client framework that supports major OS and platforms. Portsip VoIP SDK comes with APIs and comprehensive documents for a quicker integration of VoIP connectivity. The Multi-tenant PBX has the potential to handle 10K simultaneous calls per server.    

Highlights of Portsip VoIP SDK Solution

  • Inbuilt WebRTC Gateway
  • Multi-tenant Capability
  • Easy setup of SIP Trunks and BoIP PBX


Not only voice communication is seamless but also it saves ample amount of cost, time and enhances the efficiency of collaboration. Each VoIP API solution provider offers a different set of features and functionalities. Partnering with the ideal VoIP API provider is the ultimate factor in augmenting your business collaboration.