What is web speech API?
Assesses fundamental understanding of JavaScript conventions, runtime behavior, and memory/performance considerations.
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Web speech API is used to enable modern browsers recognize and synthesize speech(i.e, voice data into web apps). This API was introduced by W3C Community in the year 2012. It has two main parts:
- SpeechRecognition (Asynchronous Speech Recognition or Speech-to-Text): It provides the ability to recognize voice context from an audio input and respond accordingly. This is accessed by the
SpeechRecognitioninterface.
The example below shows how to use this API to get text from speech,
window.SpeechRecognition =
window.webkitSpeechRecognition || window.SpeechRecognition; // webkitSpeechRecognition for Chrome and SpeechRecognition for FF
const recognition = new window.SpeechRecognition();
recognition.onresult = (event) => {
// SpeechRecognitionEvent type
const speechToText = event.results[0][0].transcript;
console.log(speechToText);
};
recognition.start();
In this API, browser is going to ask you for permission to use your microphone
- SpeechSynthesis (Text-to-Speech): It provides the ability to recognize voice context from an audio input and respond. This is accessed by the
SpeechSynthesisinterface.
For example, the below code is used to get voice/speech from text,
if ("speechSynthesis" in window) {
var speech = new SpeechSynthesisUtterance("Hello World!");
speech.lang = "en-US";
window.speechSynthesis.speak(speech);
}
The above examples can be tested on chrome(33+) browser's developer console.
Note: This API is still a working draft and only available in Chrome and Firefox browsers(ofcourse Chrome only implemented the specification)
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.