Gone are the days of robotic-sounding speech generators that were limited to just a few voices. Now, we have a lot more options with advanced text-to-speech systems that connect to different applications through APIs.
Whether you’re looking to add a voiceover to a video you created or you need a customized AI-generated voice to answer questions for thousands of customers, a text-to-speech API can give you flexible options that really sound human.
In this blog post, we’ll look at text-to-speech APIs, including what they’re used for and eight of the best platforms on the market today.
What Is a Text-to-Speech API?
Text-to-speech (TTS) API, often referred to as speech synthesis, converts text into spoken words. These APIs are making it easier for users to interact with devices and are powering different applications that use natural human communication.
TTS APIs are used in a lot of the technologies we’re familiar with, from voiceover tools in applications like Instagram or TikTok to chatbots and even educational tools that turn text summaries into spoken words. Generally, these APIs come with different customizable voices as well as different languages so that the generated audio can be completely customized.
7 of the Best Text-to-Speech AI APIs
The global text-to-speech industry is on track to grow from USD 2.5 billion in 2023 to USD 6.7 billion by 2032. There’s a huge demand for this technology for both personal and professional applications, with many different TTS APIs on the market, some offering more specializations like content creation features or enterprise-grade security. Keep reading to learn more about the best text-to-speech API options and find the one that’s right for you.
1. Microsoft Azure Text-to-Speech
Microsoft Azure is a complete AI platform with multiple services, including a text-to-speech API. The TTS API itself is a powerhouse when it comes to generating high-quality, natural-sounding voices. It offers a huge variety of voices across multiple languages and lets users tweak pitch, speed, and pronunciation using Speech Synthesis Markup Language (SSML).
What really makes Azure stand out is its custom neural voice feature, which allows businesses to create custom AI-generated voices so that brands can develop a unique voice that fits their identity. Because Azure API is part of Microsoft’s ecosystem, it integrates seamlessly with other Microsoft services, which is a big plus for companies already using Azure for AI and automation.
2. Google Cloud Text-to-Speech
Google Cloud’s text-to-speech API is powered by DeepMind’s AI, which means the voices it produces sound particularly lifelike. Google’s TTS API uses WaveNet, a deep-learning model that makes synthetic speech sound more human by mimicking the way humans speak, making voices feel much more fluid and engaging. Google offers over 380 voices in more than 50 languages, giving businesses plenty of options for localization.
Users can fine-tune speech sounds with SSML controls, adjusting pitch, speaking rate, and emphasis to make it even more natural, in addition to Neural2 and studio voices for internationalization and professional narration. Google’s TTS API is widely used for virtual assistants, content creation, and e-learning applications where realistic voices can enhance the user experience.
3. ElevenLabs
ElevenLabs text-to-speech voice API offers some of the most realistic AI-generated voices on the market for content and video creators. Unlike traditional TTS solutions that can sound flat and robotic, ElevenLabs’ voices capture emotion, tone, and even speech subtleties like pauses, making them feel remarkably human. With its voice cloning feature, users can replicate and customize a real voice and use it for a specific application.
While the human-sounding voice generation makes ElevenLabs a favorite among content creators, it’s not an ideal solution for enterprises that need a more well-rounded set of speech AI and TTS features. ElevenLabs is mostly used by independent creators and small teams looking for high-quality voiceovers on a budget, whether for video voiceovers, audiobooks, podcasts, video games, or accessibility apps.
4. IBM Watson Text-to-Speech
As part of IBM Watson’s entire AI suite, there’s also a TTS service on the cloud that’s designed for businesses that need enterprise-level speech synthesis. It offers advanced enterprise-grade security, compliance, and customization. Unlike other TTS solutions that might cater to consumer applications, Watson is often used in industries like healthcare, finance, and government, where data privacy and voice consistency are essential. With multilingual support, SSML customization, and voice adaptation technology, IBM Watson allows users to fine-tune how a voice sounds.
Whether it’s adjusting the tone of a customer support bot or making medical data easier to understand, Watson’s AI is built to handle complex and professional use cases. One of Watson’s biggest advantages is its ability to integrate seamlessly with other IBM tools, making it a solid choice for businesses that already rely on IBM or Watson’s broader capabilities.
5. Amazon Polly
AWS has its own TTS API, Amazon Polly, offering scalability and natural-sounding voices for companies that need large-scale TTS. Businesses already using AWS for other AI or automation projects will find deployment seamless. Polly offers advanced security controls and also allows users to store audio files in MPS of OGG format for more control over distributions.
One of Polly’s standout features is its custom lexicons, which allow businesses to define how certain words should be pronounced. This is especially useful for industries that use a lot of specialized terminology, like healthcare or finance. Polly is used by companies that need reliable, high-quality voice synthesis, from e-learning platforms to call centers, as well as for customer service bots and assistants and audio for games and animations.
6. OpenAI Text-to-Speech
OpenAI’s text-to-speech voice API’s capabilities are relatively new, but they bring some serious advancements in realism and contextual understanding. OpenAI’s voices can capture nuances in tone, making them feel expressive and natural. Since OpenAI is behind some of the most advanced AI models in the world, it’s no surprise that its speech synthesis technology is setting new standards in how AI-generated voices sound.
Right now, OpenAI’s TTS is being integrated into various applications, including chatbots, voice assistants, and even content creation tools. It’s particularly appealing to developers who want cutting-edge AI speech synthesis that keeps improving. While it’s not as widely used as some of its competitors, OpenAI’s text-to-speech AI is highly versatile easy to integrate, and customizable, making it a good fit for a range of applications.
7. Descript Overdub
Descript is an end-to-end video editor specifically designed for content creators, podcasters, and video editors with strong AI voice features. Users can clean up narration, use artificial voices in multiple languages, and even clone their own voice and generate AI-powered speech that sounds just like them with the overdub feature. This means podcasters or video creators can make quick edits to their content without needing to re-record entire sections.
While many other TTS APIs cater more to businesses and enterprises, Descript targets creators with features that help them work faster and more efficiently. It’s a popular tool for social media influencers, YouTubers, and media professionals who need quick and reliable voice edits.
What to Look for When Choosing a Text-to-Speech API
The essence of most TTS API applications may be the same, converting text into speech, but the way each software arrives at the outcome can look different. Not only that, but some APIs cater to more specific use cases, while others are more fitting for larger companies. Before jumping straight into one tool or another, consider a few different factors to help you choose the best text-to-speech API for your requirements.
- Define your needs: Before choosing a TTS API, make sure you understand your goals and needs for this software, whether it’s hyper-realistic voices, being able to customize a real voice, or offering multilingual support, for example
- Find the best API for your use case: A lot of APIs are more suited to different use cases, for example, ElevelLabs or Descript are more appropriate for content creators while IBM Watson and Microsoft Azure are more fitting for enterprise-grade business applications
- Cost and scalability: Some APIs charge per character, others per request, but each has its own pricing structure and subscription models, so it’s important that your chosen API fits both your budget and scalability requirements as your needs evolve
- Security and compliance: Depending on your industry, you may need high-level security and compliance features, which some enterprise-focused solutions provide
- Customization options: Certain APIs give you more control over customization, with voice cloning features that help you create a voice that matches your brand’s identity
- Audio quality and latency: Not all TTS applications sound the same or respond at the same speed, so if you need an API for real-time interactions, you want an API that’s highly responsive and clear
Make the Most of Speech AI With an End-to-end Platform like aiOla
Many companies can actually benefit from full-service systems that use speech AI technology in a more advanced way. Rather than using software that can only turn text into speech, platforms like aiOla can help teams accomplish a lot more by harnessing the power of speech to automate tasks, trigger actions, cut down on manual tasks, and collect essential data.
aiOla is a flexible and easy-to-implement solution that drastically helps frontline workers make the most of the tools they’re already working with, whether it’s cutting down on inspection time for logistics teams or getting real-time insights on predictive maintenance needs in manufacturing. Thanks to aiOla, companies have been able to:
- Reduce compliance risks by 20%
- Improve customer satisfaction levels by 35%
- Increase time savings by 55% by cutting down on manual, redundant tasks
With aiOla, all users need to do is use their voices to activate the platform and trigger speech AI-powered automations and workflows. Not only does this help teams work more efficiently, but also helps increase safety when workers are more focused on their primary tasks.
Enhancing Applications with Advanced Text-to-Speech Technology
Brands can benefit from TTS APIs in more ways than one: they can save on costs, reduce the resources and manpower they need, cut out manual work, and offer better customer support. However, reaping the benefits of TTS API technology involves choosing the best platform to begin with. With a speech AI platform like aiOla, users get the best of all worlds, with TTS technology and much more to help workers perform essential tasks more efficiently.
Schedule a demo with one of our experts to learn more about how aiOla can help you harness the power of speech.
