10 Best VoIP Call APIs & SIP Call Software in 2025 Reviews

Are you wondering What, Which, and How about SIP calling APIs? You’ve landed right!

Alright, the purpose of SIP calling in 2025 is sky-high. Small businesses or startups that switch to SIP calling reduce the cost of their local calls by 40% and 90% on international calls.

In the upcoming years, while technological advancement and customer expectations over brands increase, the need for a sound communication system will eventually peak. Well, it’s already. 

The answer to the How is definitely SIP calling for its flexible, affordable and scalable solutions. 

But Which is a daunting task for many individuals and enterprises. No more! In this blog, we’ve covered a detailed review of the top 10 SIP calling APIs in the industry to build your voice and chat system. 

What is the SIP Calling API?

Session Initiation Protocol (SIP) allows users to communicate with others by sharing voice, video, messages, and files over the Internet. 

SIP calling API lets developers integrate the SIP functionalities into their existing systems using pre-built functions and SDKs (software development kits). 

When choosing the best SIP calling API provider, apart from the provider you must have several criteria to guide the selection process.

• Variety in API Features: Look for the API features that are collectively pre-built with communication capabilities in all aspects. 
• API’s Popularity & Market Demand: Look for the demand and popularity of the voice call API in the market. This evaluation helps you determine the value and relevance. 
• Pricing & Investment: Cost and pricing play a vital role in the development process. Evaluate the pricing and investment required for the API. Looking for a free trial will be a great chance to evaluate efficiently.

Compatibility & Integration: Keep in mind that the API should align with your existing infrastructure. Ensuring compatibility and integration is paramount.

Top 10 SIP VoIP Calling Software for Unlimited Voice Call

The 10 best SIP VoIP API providers are 1.MirrorFly, 2.Twilio, 3.Nextiva, 4.Vonage, 5.Apphitect, 6.Sendbird, 7.Plivo, 8.VideoSDK, 9.Sinch, and 10.Quickblox. 

1. MirrorFly – White-Label VoIP SIP API for Unlimited Calls

MirrorFly is a leading provider of white label voice API that covers SIP and VoIP call functionalities. This platform is scalable with a global infrastructure that supports 1 billion concurrent conversations. 

Without any limitations, users can make real-time voice calls, instant messaging, and WebRTC-based video conferencing on any platform across devices. 

Also, MirrorFly supports fast integration and custom security protocols with end-to-end encryption. The ultra low latency communication supports 99.999% uptime SLA. 

MirrorFly’s Audio Call Features

• 1:1 voice call
• Unlimited group calls
• Multi-tenancy support
• 100% customizable APIs and SDKs
• One-time license fee

Pros of MirrorFly

• Flexible and customizable API
• Dedicated developer support
• End-to-end integration and migration 
• Upload and send multimedia files without any size

Cons of MirrorFly

• Set-up process might take time. 

MirrorFly’s VoIP & SIP Offerings

1. MirrorFly Cloud Solution: This SaaS solution offers pre-built solutions with UI kits and multi-tenancy support with real-time end-to-end chat features.
2. Self-Hosted Voice Chat Solution: This SaaP solution provides complete customization with custom branding, personalized features, and one-time cost for white-label SIP calling solutions.

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2. Twilio – (Programmable Voice API for Unlimited VoIP Calling)

Twilio is a programmable voice API that aims to improve both internal and customer-business communication. Twilio supports personalized interactions through text messages and phone calls across any channel. 

With REST API, developers can easily integrate voice chat functionalities for regular phone calls, however, accompanied by certain limitations.

Twilio’s SIP Audio Call Features

• Inbound and outbound SIP calls
• Call monitoring and analysis
• Language compatibility
• In-progress call modification

Pros of Twilio

• Global infrastructure support
• Third-party integrations
• Both internal and client communication support
• Sending and receiving messages and making phone calls

Cons of Twilio

• Poor customer support
• High pricing 
• Requires technical support

3. Nextiva – (Scalable VoIP API with Flexible Pricing)

Nextiva offers one of the most reliable SIP VoIP APIs for seamless voice call connection. With the guided support and migration process, enterprises can build smart and scalable SIP voice call solutions across a variety of devices.

The robust set of Nextiva’s API enables it to build one-on-one and group VoIP calls that connect globally on the WebRTC platform. 

Nextiva Voice Call Features

• Carrier grade PSTN connectivity
• Detailed call records
• Rapid setup and migration
• Interactive voice response
• Voice broadcasting

Pros of Nextiva

• Comprehensive feature set
• Highly scalable 
• Easy integration other Nextiva platform
• Strong customer support

Cons of Nextiva

• Potential learning curves
• High competitive pricing

4. Vonage – (WebRTC & PSTN SIP Calling)

Vonage voice call API is not just about making phone calls; you can lead the customer-business conversation and deliver a better experience. With Vonage, WebRTC, and PSTN can be personalized based on the user context and business requirements. 

With multiple use cases, Vonage API can be employed for healthcare, education, retail, finance, logistics, and travel for SIP calls. 

Vonage Voice Call Features

• Customizable programming voice call API
• Contact center with IVR and intelligent support
• Web socket connectivity 
• AI integrations
• AI Studio
• Automatic Speech Recognition

Pros of Vonage

• Global reach
• Flexibility
• Free trial available
• Developer friendly

Cons of Vonage

• Limited customization options
• Complex pricing

5. ApphiTect – (Self-Hosted VoIP Calling API)

Apphitect is a leading SIP voice-calling solution with self-hosted APIs and SDKs for Android and iOS. Apphitect is built with real-time voice and chat functionalities with high end customization. Based on enterprise needs, users can personalize each feature and branding by adding a logo, brand color, and fonts.

Apphitect allows 100+ third-party integrations and its API is flexible to scale up with multi-faceted features. Apphitect voice APIs offer custom security and compliance with industry standards. 

Apphitect SIP Calling Features

• Seamless VoIP SIP Call
• One-on-one and group voice calling
• Push notifications
• Call recording
• Audio broadcasting and encryption

Pros of Apphitect

• Dedicated customer support with detailed SDK documentation
• 99.999% uptime SLA
• Flexible hosting
• Zero downtime

Cons of Apphitect

• No free trial available

6. Sendbird – (Secure SIP Calling Platform)

Sendbird voice communication API offers high-quality SIP audio calls with well-managed infrastructure for a high scale of conversations. This platform allows personal and private group calls with a highly secured layer. 

With highly reliable chat platform infrastructure delivering scalable and immersive calling experience. Still, the pricing structure may not fit for small businesses or startups. Ensuring a detailed pricing analysis before choosing Sendbird is recommended. 

Sendbird’s Key Features

• Flexible and customizable communications APIs
• Custom user ID with chat
• Call history and contact masking
• Multi-device support
• Push notifications

Pros of Sendbird

• Easy to use interface
• Secure and complete suite of communication
• Dedicated support team

Cons of Sendbird

• Limited customization
• Documentation needs more improvement

7. Plivo – (Cloud-based Global Chat & SIP Call Provider)

Plivo is a comprehensive chat and voice integration solution provider with a wide range of carrier network connections. As a global SIP provider, Plivo delivers seamless connectivity across 195 countries through the direct connection of over 1600 local carrier networks.

With extreme chat and voice features, Plivo allows enterprises and developers to build their communication apps through SIP SDKs and APIs.

Plivo Native SIP SDK Features

• Dedicated call monitoring and transfer
• 1:1 audio calls and group conferencing
• Call recording and routing
• SIP gateway and devices
• Voice alerts and quality analysis

Pros of Plivo

• Easy integration & global support
• Intuitive user interface
• 24/7 customer support
• Detailed documentation

Cons of Plivo

• Not showing caller ID 
• API shows errors most of the time

8. VideoSDK – (Flexible & Versatile Audio Call Software)

VideoSDK is an extraordinary voice call integration solution with versatile API and SDK for both mobile and desktop. With ready-to-integrate SIP functionalities and pre-built UI kits enabling audio calls in an existing system is now more accessible for developers and businesses.

A highlighted feature of VideoSDK is its cross-platform compatibility and voice call features that support all use cases. It supports a wide array of programming languages and frameworks like JavaScript, ReactJS, React Native, Android, and Flutter.

Key Features of Video SDK

• Global infrastructure for every use case
• Customizable UI
• High adaptive bitrate for immerse audio quality
• Call auto connect feature
• Role based permission

Pros of VideoSDK

• Unlimited parallel room
• High availability with zero maintenance
• Quick time to reach market

Cons of VideoSDK

• Complex pricing
• Poor customer support

9. Sinch – (Real-Time VoIP Service Provider)

Sinch is one of the leading real-time SIP and VoIP service providers with the best voice call functionalities across Android, iOS, and the web. Along with SIP calling, Sinch supports SMS, instant messaging, group calling, and video conferencing via standard communication APIs. 

Although there are some issues associated with call drops, audio quality has been reported. Analyze Sinch voice call API to evaluate whether it will suit your specific requirements. 

Sinch SIP API Features

• Contact and number masking
• In-app voice calling & chat support
• Cross platform support
• Flexible & reliable APIs

Pros of Sinch

• Easy integration with other channels
• Developer friendly documentation 
• Route management

Cons of Sinch

• Need improved UI
• Issues with audio quality

10. Quickblox – (Excellent Infrastructure for Global SIP Connection) 

Quickblox is a leading and feature-rich SIP calling provider with powerful APIs and a toolkit for complete voice call solutions. With the ready-to-go module, developers, and enterprises can choose Quickblox to hit the market without any complex steps quickly.

These SDKs are supported by WebRTC-based connection for seamless peer-to-peer connectivity with encryption.

Key Features of Quickblox VoIP API

• VoIP phone calls
• Remote media track
• Chat and video conferencing
• Push notifications

Pros of Quickblox

• Dedicated customer service
• Participant can create maximum groups 
• Easy to use interface

Cons of Quickblox

• Limited customization on UI
• Lack in multi-language chat

It’s Your Time to Choose the Best SIP Call Provider

Every SIP calling provider, SDK has its pros and cons. When it comes to choosing the best one, it’s wholly based on your specific requirements and needs. 

As a pro tip: it’s always recommended to choose the white-label solution to have complete access to the features, branding, customization, and source code. These factors in your SIP provider will support both your ongoing requirements as well as upcoming high scalable options.

From our list to narrow down the options, we recommend MirrorFly, Apphitect, and Twilio for their extended customization and self-hosted solutions.

Contact the provider to get more detailed information for quick integration! 

Good luck with finding the best VoIP calling Software!

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