A Speech to Text API (Application Programming Interface) is a software tool that allows developers to build applications that can transcribe spoken words into text. It uses machine learning algorithms to analyze and convert audio files, such as recorded voice memos or live speech, into written words. Speech to Text APIs are commonly used in various applications such as transcription software, voice-activated assistants, and closed captioning services. With speech to text technology, users can easily convert spoken words into text for editing, search, or sharing.