Best Voice Calling API & SDK Providers with a Free Trial of 2025

Sendbird’s Voice and Video APIs give companies the tools they need to incorporate top-notch, real-time voice and video communication into their applications. These APIs accommodate both one-on-one and group calls, offering a comprehensive array of features, including video mirroring, call muting, and screen sharing, to deliver a smooth and interactive experience for users. The platform also boasts multi-device and cross-platform functionality, along with robust security measures such as media stream encryption and compliance with HIPAA regulations. Perfect for sectors like healthcare, e-commerce, and social networking, Sendbird allows businesses to develop engaging and secure communication solutions without the burden of complicated development processes.

Twilio's Voice Calling API and Software Development Kits (SDKs) provide a robust solution for businesses seeking to incorporate voice communication features into their applications. This integration facilitates a smooth and effective method for engaging with customers via phone, allowing companies to enrich their customer interaction strategies with tailored and immediate voice conversations. With the Voice Calling API, businesses can programmatically initiate, receive, and manage calls, granting them significant flexibility and oversight over their voice interactions. This functionality is essential for organizations aiming to streamline call processes, such as support lines, appointment notifications, or sales outreach, thus enhancing operational productivity and improving customer experiences. Twilio's Voice SDKs are compatible with multiple platforms, including Android, iOS, JavaScript, and React Native, enabling developers to create voice-capable applications that can operate across a variety of devices.

ClickSend offers SMS, MMS, Voice, Online Mail, Email and Fax software for businesses. Our communications and messaging tools are simple to use, automate and integrate. That’s why they’re used by some of the most trusted brands, organisations and developers globally. Built for all, you can access ClickSend via our Dashboard, mobile app, flexible API or 900+ integrations. Plus, ClickSend offers helpful 24/7 support, and lightning fast delivery via a secure and reliable platform. From SMS marketing and alerts to bulk mailouts sent from your browser, join over 90,000+ businesses sending communications around the world. Our 100% uptime guarantee and lightning fast direct routes provide reliable messaging, no matter the channel. From small businesses to enterprise, ClickSend powers billions of messages around the world with 232+ direct carrier connections. Plus, ClickSend is always pay-as-you-go. That’s why ClickSend is business communications, solved.

MirrorFly is a custom CPaaS provider powering businesses and enterprises with real-time communication, such as instant messaging, voice calls, and video conferencing through Chat APIs and SDKs. Regardless of the use case, tech stack, and devices, MirrorFly supports brands across the world to build their own chat platform with complete customization and zero limitations. MirrorFly’s Key CPaaS Benefits: ✅ Host on Your Own Server ✅Unlimited Customization ✅ Complete Data in Your Hand ✅ 1000+ Features ✅ Custom Security (Gmail, Phone, BioMetric, etc) ✅ Upload Enlarged Files (3+ GB) ✅ Mulit-tenant Server ✅ Scale 1+ Billion Concurrent Users ✅ Free Migration & Integration ✅ Hire Your Own Dedicated Team

EnableX makes it easy to integrate real-time communications into applications or workflows. It was designed and developed for Service Providers and Systems Integrators. It provides a robust, scalable, secure communications platform without the complexity and maintenance of maintaining the network infrastructure. Developers can quickly customise and embed all of the communication functions, such as voice, video, and SMS, into existing applications, workflows, and systems by simply using EnableX's extensive sets of programmable SDKs and APIs. Businesses can communicate with customers worldwide using the Virtual Number services, as well as advanced features like AI and NLP.

Connect with your customers like never before across all channels. With CPaaS and APIs for SMS, Voice, Video, and Verification, you can reach any mobile device globally in mere seconds. By effectively engaging your customers, you can significantly increase webshop orders, a fact proven by our collaboration with a leading telecommunications company that utilized a user-friendly online chatbot. Additionally, we assisted a prominent automotive firm in re-engaging potential buyers who had not responded to emails, leading to impressive results from their tailored Rich SMS campaign. Are your clients missing important appointments? Implementing engaging SMS reminders not only benefits them but also enhances your revenue streams. Trusted by developers worldwide, our solutions allow you to build with assurance and elevate your business using just a few lines of code. Strengthen your connection with customers and enhance their journey at every touchpoint, ultimately driving greater satisfaction and loyalty. Embrace this opportunity to transform your customer interactions and watch your business thrive.

Plivo Communications Platform is a Cloud API Platform as well as a Global Carrier Services Provider. It offers high-quality cloud communications at an affordable price. Plivo Communications Platform allows users to make phone and SMS calls to all countries. It also allows them to buy local numbers in 55 countries. Plivo Communications Platform offers free tech support that is available 24/7. Experts are happy to help customers with any issues.

AVOXI Genius is a cloud-based call center software that is efficient, budget-friendly, and user-friendly. It allows you to effortlessly oversee your business communications through a straightforward, web-based contact center interface. This innovative platform uniquely combines your voice service with your contact center solution, offering virtual phone numbers that can be activated instantly in over 170 countries. With pricing beginning at just $19.99 per user, AVOXI Genius stands out as one of the most cost-effective options available globally. Additionally, for a limited time, you can enjoy two months free with your subscription, making it an even more enticing choice for businesses looking to enhance their communication capabilities.

CometChat is a live chat platform that allows users to collaborate and connect with customers. Developed with API and Chat SDK, CometChat can be deployed on-premise and cloud. The solution enables users to video, text and voice chat with the customers, share pictures via broadcast videos, play games and use whiteboards. Primary features of CometChat include WebRTC, file sharing, screen sharing, real-time language translation, customization for layouts, languages and colors, typing indicators, last-seen notifications, read receipts, emojis and stickers. The platform also allows users to switch from text chatting to a video chatting interface. Additional services of CometChat include broadcast messages, guest login support, earlier messages, blocking or unblocking users, video broadcasting and voice notes. Pricing of the product is based on monthly active users and support is extended via email and phone.

Create a scalable voice experience with the API that connects millions globally. With Twilio Voice, you can build unique phone call experiences with one API, to create, receive, control and monitor calls with just a few lines of code. Customize your experience the way you want by using a wide range of customization resources, such as our Voice SDK, speech recognition, Interactive Voice Response (IVR), and recording transcriptions. Whether you're looking to set up global conferencing or alerts & notifications, Twilio has the support you need for building with Voice, such as our Twilio Runtime and Studio developer tools. Find docs, code samples, and helper libraries to start building today.

Authkey.io stands as an exceptional Enterprise Omni Channel API platform, offering an extensive suite of communication tools and APIs meticulously designed to empower businesses in their quest for efficient and secure customer engagement. SMS API:A seamless communication symphony with its event-based messaging prowess. This facet encompasses the seamless orchestration of Bulk SMS delivery, transactional messages, one-time passwords (OTP), and the authentication process through call-based interfaces. Voice API: This dynamic capability ensures the delivery of OTPs through vocal messages, providing an alternative avenue that ensures the recipient's prompt access. Email API: Reliable and rapid delivery of emails, serving critical functions such as password verification, account creation, OTP distribution, and email validation. WhatsApp Business API: The contemporary business landscape requires a direct conduit to reach the massive audience on the WhatsApp API facilitate this engagement, enabling businesses to establish a direct line of communication with their audience. Two-Factor Authentication (2FA) API: Seamlessly dispatching OTPs, verifying logins, and bolstering the security architecture of business software, CRM systems.

You don't have to spend months creating in-app messaging feeds and messaging. Instead, you can implement them in as little as a matter of weeks using Stream's activity feeds or in-app chat APIs. Stream's flexible UI kits, reliable APIs, and developer-friendly SDKs allow product teams to quickly integrate polished communication functionality found on social media platforms like Instagram, Facebook Messenger, or WhatsApp. Stream's APIs have an industry-leading 99.999% uptime guarantee, more than a billion users, and 5,000,000 concurrent connections. This makes them highly scalable and ideal for both enterprise-grade businesses as well as growing startups. Easy-to-use software components make it easier to ship fully-featured activity feeds, in-app chat functionality, and other features faster. This gives your product an edge.

With over 700 direct carrier connections and 60+ offices on 6 continents, Infobip is a global leader in omnichannel communication. We make it our business to simplify how brands connect with, engage and delight their customers at global scale. Our programmable communications platform delivers a suite of tools for advanced customer engagement and support, plus security and authentication. We make this available to you across the widest range of communication channels possible. THE INFOBIP ADVANTAGE (1) Personalized omnichannel customer connections Achieve deeper customer engagement across the widest selection of local and global channels, including: SMS, RCS, WhatsApp, voice, video, email and the most popular chat apps. (2) Global reach, local presence Our 60+ offices around the world allow us to react faster. We provide 24/7 customer support, technical solutions in-line with needs and local requirements — based on proven best practices. (3) Full stack customer engagement Deliver better outcomes for your business by enhancing your communications with fully integrated contact center, marketing automation, and chatbot building solutions informed by our customer data platform.

Mesibo serves as a robust real-time communication platform that enables the seamless integration of messaging, group chats, voice calls, and video conferencing into both mobile and web applications. When developing the Mesibo APIs, our primary focus was on ensuring reliability, performance, and scalability, as we recognized that overly complex APIs can lead to unnecessary complications and increased error rates in applications. Rather than following the trend of convoluted API designs, we have prioritized simplicity while maintaining powerful capabilities. In this section, we will delve into the intricacies of Mesibo's real-time APIs. It is advisable to check out the source code of one of the sample applications available on GitHub to gain insights into how these APIs are effectively utilized. This approach will facilitate your ability to write cross-platform code seamlessly. In the subsequent sections, we will outline the APIs along with their respective names and parameters, providing you with a comprehensive understanding of their functionality. Additionally, this will empower you to implement the APIs more effectively in your projects.

Provide prompt and tailored communication through international SMS/RCS and voice cloud services. Enhance your customer insights with actionable intelligence derived from global phone numbers and subscriber data. Utilize TeleSign’s Messaging API to code once and effectively reach your audience at scale, leveraging seamless delivery across various channels. The TeleSign Messaging API supports SMS, RCS, and WhatsApp, empowering you to create secure digital interactions that engage customers globally. By integrating a unified Messaging API, you can begin dispatching dependable and secure messages via SMS, RCS, and WhatsApp to your clientele today. Opt for one, two, or all three channels to diversify your programmable messaging approach and broaden your reach. With over 120 optimized points-of-presence and more than 700 direct-to-carrier routes, connect with an even larger customer base effortlessly. This expanded network ensures your messages are delivered efficiently and effectively.

A flexible communications cloud with advanced APIs to voice and SMS Video and audio designed by the original geeks in software-defined telecom.

Exotel is a cloud-based business phone system that is reliable and secure. It is easy to set up. No additional infrastructure or equipment is required. It allows sales and support teams to work from anywhere. Your customers will enjoy a personalized calling experience. Exotel's drag-and-drop builder makes it easy to track, manage, and build call flows. Easy setup of SMS campaigns. We guarantee the best delivery rates. Delivery to more than 190 countries. Easy user verification via SMS and calls. The best success rates and non-intrusive.