OpenAI has announced an API for accessing new AI models it develops. The new API takes a different approach from typical AI systems. Most AI systems are designed for specific use cases. OpenAI considers its offering a "general-purpose" AI system provided by a "text in, text out interface."
If it's speech-to-text services you're after, Vocapia Research is in the game, offering a variety of speech technology services and working with their clients to adapt, fine tune or create products that are relevant for specific applications. One of Vocapia's products is the VoxSigma speech-to-text software suite that is suitable for many languages and a variety of audio data types. The VoxSigma API is available as a Web service via a REST API over HTTPS.