Best Voice Calling API & SDK Providers with a Free Trial
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Compare the Top Voice Calling API & SDK Providers with a Free Trial as of October 2025
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What are Voice Calling API & SDK Providers with a Free Trial?
Voice calling API and SDK providers offer developers with the necessary tools to integrate voice calling functionality into their applications. These providers typically offer a range of options, including APIs that allow for an easy integration process, as well as SDKs that provide more advanced features such as call recording and real-time transcription. They also often provide comprehensive documentation and technical support to assist developers in implementing these services. Some of the major players in this field include Twilio, Voximplant, and Nexmo, each offering their own unique set of features and pricing plans. In general, these providers aim to make it easier for businesses to incorporate voice calling capabilities into their products without having to build them from scratch. Compare and read user reviews of the best Voice Calling API & SDK providers with a Free Trial currently available using the table below. This list is updated regularly.
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1
Sendbird
Sendbird
Sendbird’s Voice and Video APIs empower businesses to integrate high-quality, real-time voice and video communication into their apps. With support for both direct and group calls, these APIs provide a rich set of features such as video mirroring, call muting, and screen sharing, ensuring a seamless and interactive user experience. The platform supports multi-device and cross-platform capabilities, along with strong security features like media stream encryption and HIPAA compliance. Ideal for industries such as healthcare, e-commerce, and social platforms, Sendbird enables businesses to create engaging and secure communication solutions without complex development overhead.Starting Price: $399/month -
2
Twilio
Twilio
Twilio's Voice Calling API and SDKs empower businesses to integrate voice communication capabilities into their applications, providing a seamless and efficient way to connect with customers over the phone. This integration allows businesses to enhance their customer engagement strategies by offering personalized and real-time voice interactions. The Voice Calling API enables businesses to make, receive, and manage calls programmatically, offering a high degree of flexibility and control over voice communications. This capability is crucial for businesses looking to automate call workflows, such as customer support hotlines, appointment reminders, or sales calls, thereby improving operational efficiency and customer satisfaction. Twilio's Voice SDKs support various platforms, including Android, iOS, JavaScript, and React Native, allowing developers to build voice-enabled applications across different devices.Starting Price: $0.0085 per min -
3
ClickSend
ClickSend
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.Starting Price: $20 minimum topup -
4
MirrorFly
CONTUS TECH
MirrorFly is a CPaaS platform that empowers businesses and enterprises to add real-time chat features into their existing applications and websites. MirrorFly CPaaS offers text, voice, video, and broadcasting in an enterprise-grade infrastructure. Startups and large enterprises can build their own chat app with extensive customization and branding capabilities to add logos, brand color, and other brand elements. The self-hosted Chat APIs and SDKs offer 1000+ in-app messaging features with 100% customization. In addition, MirrorFly offers a dedicated developer team to support the end-to-end custom chat app development process. MirrorFly Readymade SDKs: 1. In-app Chat API 2. HD Video Call Solution 3. HQ Voice Call SDK 4. Self-hosted Chat Messaging Solution 5. SIP & VoIP Call Solution 6. Flutter Flow Software 7. Activity Feeds Solution 8. Call Broadcasting 9. Video Conferencing API 10. Video KYC Solution 11. Live Streaming SDKStarting Price: $299 per month -
5
EnableX Communications APIs
vCloudx
EnableX makes integrating real-time communications into applications and workflows a lot easier. Designed and developed for Service Providers, Systems Integrators, and Developers, it provides a robust, scalable and secure communications platform without the complexity of building and maintaining the network infrastructure. By simply leveraging on EnableX comprehensive sets of programmable APIs and SDKs, developers can rapidly customize and embed all or part of the communication functions – voice, video, SMS and chat – right into existing applications, workflows and systems. Together with the Virtual Number services and advanced features such as AI and NLP, businesses can reach customers globally with an outstanding communication experience. -
6
Plivo
Plivo
Access high-quality cloud communications at a low cost with Plivo Communications Platform, a Cloud API Platform and a Global Carrier Services Provider. Plivo Communications Platform enables users to make phone calls to all countries, buy local phone numbers in 55 countries, send SMS to all countries, and more. Available 24/7, Plivo Communications Platform also features free tech support by experts that are happy to assist customers with their issues.Starting Price: $.005 / SMS -
7
AVOXI
AVOXI
The effective, affordable, and easy-to-use cloud-based call center software, AVOXI Genius. Easily manage your business communications from an intuitive, web-based contact center. AVOXI Genius is the first platform to integrate your contact center solution with your voice service, with virtual phone numbers available for instant activation in 170+ countries. With plans starting at $19.99 per user, AVOXI Genius is one of the most affordable solutions worldwide! Get 2 months free--limited time only.Starting Price: $19.99/month/user -
8
CometChat
CometChat
CometChat is a chat API and in-app messaging SDK (software development kit) that enables users to integrate HD voice and video calling, as well as text chat functionality directly into their mobile and web apps. CometChat also supports features such as push notifications, read receipts, typing indicators, real-time translation, and more. CometChat allows users to create their own user interface for private or group chat applications. Customization tools let users personalize various elements of their chat app. The platform also provides users with the tools to add voice, and video calling and conferencing capabilities to their apps or websites. Users can also send and receive media files through CometChat, as the platform enables users to sync and share files like GIFs, photos, videos, and audio clips. Support for custom payloads mean users can send calendar invites, or share information like their location or event details to chat participants.Starting Price: $109.00/month -
9
Twilio Voice
Twilio
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. Create an engaging voice experience that you can quickly scale and modify with a wide array of customization options and resources, like our Voice SDK. Then, add on features like Interactive Voice Response (IVR), recording transcriptions, and speech recognition to create an experience that your customers will appreciate. Whether you're looking to set up global conferencing or alerts & notifications, Twilio has the support you need for building with Voice. Find docs, code samples, helper libraries, and developer tools such as Twilio Runtime and our visual workflow builder, Studio.Starting Price: $0.0085 per min -
10
Authkey
Authkey.io
Authkey is a multi-channel CPaaS platform providing SMS API, WhatsApp Business API, Voice API, Email API, and Google RCS. It helps businesses send notifications, promotional messages, transactional messages, OTPs, 2FA, and more. Designed for responsiveness and ease of use, Authkey allows you to start without adding any credit cards. Authkey offers a free sandbox account for building, testing, and deploying. It supports easy-to-integrate APIs for all channels and over 1,000 automation options via Zapier, Pabbly, Integrately, and other partners. You can easily push bulk campaigns through all channels. WhatsApp Chatbot for intelligent customer query responses. Join over 200 active businesses working with us and grow together.Starting Price: $0 -
11
Stream
GetStream.io
Why spend months building in-app activity feeds and messaging from scratch when you can implement in just weeks with Stream's activity feeds and in-app chat APIs? Stream's reliable APIs, developer-friendly SDKs, and flexible UI kits enable product teams to quickly integrate polished communication functionality often found in social media platforms such as WhatsApp, Facebook Messenger, and Instagram. With an industry-leading 99.999% uptime SLA, over a billion end users, and 5 million concurrent connections recently supported in a single chat channel, Stream's APIs are highly scalable, making them ideal for enterprise-grade businesses and growing startup platforms alike. Ship fully-featured activity feeds and in-app chat functionality faster with easy-to-use software components that give your product a competitive edge. -
12
Infobip
Infobip
Infobip is a global leader in omnichannel engagement powering a broad range of messaging channels, tools and solutions for advanced customer engagement, authentication and security. With over 700 direct carrier connections and 60+ offices on 6 continents, Infobip is the #1 choice of some of the world's biggest companies to scale their customer communications. We help our clients and partners overcome the complexity of consumer communications, grow their business and enhance customer experience, all in a fast, secure and reliable way. With Infobip, you can achieve deeper customer engagement across the widest selection of local and global channels, including: SMS MMS RCS Live Chat WhatsApp Business Apple Messages for Business Facebook Messenger Instagram Business Telegram Viber Voice / VOIP Video Email -
13
mesibo
mesibo
mesibo is a powerful real-time communication platform to quickly add robust real-time messaging, group chat, voice, and video calls, conferencing into your mobile and web applications. The key objectives while designing mesibo APIs were reliability, performance, and scalability. We have seen APIs as complex as the universe making apps unnecessarily complex and error-prone. We have instead worked hard to make mesibo APIs simple, yet powerful. In this section, we will explore mesibo real-time APIs in detail. It is highly recommended that you also refer to the source code of one of the mesibo sample app in GitHub to learn how APIs are used. This makes it easy for you to write cross-platform code across platform. In the following sections, we will describe APIs with name and parameters. -
14
TeleSign
TeleSign
Deliver timely, personalized information through global SMS/RCS and voice cloud communications. Gain a deeper understanding of your customers from actionable global phone number and subscriber data intelligence. Code once and message your customers at scale using TeleSign’s Messaging API - complete with waterfall delivery between channels. TeleSign Messaging API includes SMS, RCS, and WhatsApp to help you build secure digital communications that connect you with your customers anywhere in the world. Integrate a single Messaging API and start sending reliable, secure SMS, RCS and WhatsApp messages to your customers today. Choose one or all three channels to broaden your programmable messaging strategy and expand your audience. Reach more customers with 120+ optimized points-of-presence and 700+ direct-to-carrier routes. -
15
SignalWire
SignalWire
An elastic communications cloud with advanced APIs for voice, SMS and video designed by the original geeks of software-defined telecom. When your audience is large, your brand is premium, and you won't settle for janky video conferencing UX, you want this. Real time, granular control over call flows, routing, and codecs. 300% more responsiveness than you get with REST. If you use AI in your voice apps, you just found your new favorite API. If you're more comfortable with REST than WebSockets or already use TwiML, these APIs are like TwiML...if TwiML suddenly knew Kung Fu. The SMS API makes it easy to move your expensive SMS traffic to SignalWire and cut your billio 50-80% in the process. Launch and scale communication products on infrastructure built for this decade and the next rather than running aground on the limitations of 2010s-era SaaS. Persistent, bi-directional connections between your video and voice apps and our infrastructure means 300% more responsiveness. -
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Exotel
Exotel
Exotel is a secure and reliable business phone system on the cloud. Simple to setup. No additional infrastructure or equipment required. Enables sales and support teams irrespective of where they work from. Build a personalized calling experience for your customers. Track, manage and build call flows using Exotel with our drag-drop builder. Set up SMS campaigns with ease. We promise you the best delivery rates. Delivery to over 190 countries. User verification made seamless over calls & SMS. Non intrusive, with the best success rates. Make it easy for your agents to make sales calls to prospective customers. Automated dialers, integrations with CRMs, etc. make it a productive experience for your sales teams. -
17
Sinch
Sinch
Engage your customers like never before - on any channel. CPaaS and APIs for SMS, Voice, Video & Verification. Reach every mobile phone on the planet, in seconds or less. Engaging your customers the right way can help you more than double webshop orders. We know - we helped a major telco company do just that with a friendly online chatbot. We helped a major automative company re-engage and convert end-of-funnel prospects not responding to email. The results of the personalized Rich SMS campaign speak for themselves. Are your customers missing appointments? Engaging SMS reminders help both them and you, making you more revenue. Tried and trusted by developers around the world. Build with confidence and boost your business - with just a few lines of code. Get closer to your customers and add value to every step of their journey.
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