Claude API integration into existing website

We are looking for a developer to integrate speech-to-text functionality into our existing learning application. The app is built on Next.js for the frontend, with a Node.js and Express.js backend, and uses PostgreSQL as the database. The goal is to allow users to record audio or speak directly into the app and have their speech converted into accurate text in real time. We want to use the Claude API to handle the transcription and processing side of this feature. The integration should work smoothly within our current setup without disrupting existing functionality. Requirements include setting up the API connection securely, building the audio input handling on the frontend, processing and returning transcribed text, and storing relevant data in our PostgreSQL database where needed. The developer should follow clean coding practices and ensure the feature is scalable and easy to maintain. Ideal candidates have prior experience with API integrations, working knowledge of the mentioned tech stack, and familiarity with speech-to-text or AI based tools. Please share relevant past work when applying.