Generate speech from text using Gemini 2 5 Flash TTS, Angular and Firebase

In this technical walkthrough, I present a deep dive into building a high-performance Text-to-Speech (TTS) pipeline using Google Gemini 2.5 Flash, Angular v21, and Firebase Cloud Functions (Gen 2). Low latency is the ultimate goal of any AI-driven web application, and I demonstrate how to move beyond simple file downloads to implement advanced streaming techniques. By combining Gemini 3 Flash Preview for intelligent text generation with the high-speed TTS capabilities of Gemini 2.5 Flash, we can create immersive user experiences that respond almost instantly.

I cover three distinct architectural approaches for audio delivery, ensuring you have the right tool for any scenario. First, I demonstrate the traditional "Sync" method, where the backend generates a full Base64-encoded WAV file. Second, I walk through a "Stream" approach, where audio chunks are sent to the frontend in real-time and stitched into a single Blob URL—I specifically explain how to dynamically construct a 44-byte WAV header once the total stream length is known. Finally, I present the "Pro" method using the Web Audio API. By piping raw PCM data directly into the browser's AudioContext, we achieve near-zero latency, allowing the user to hear the first word while the rest of the sentence is still being synthesized by Gemini.

Throughout the video, I provide a comprehensive code walkthrough of both the Node.js backend and the Signal-based Angular frontend. You will see exactly how to use the `acceptsStreaming` flag in Firebase v2 to handle dual response types and how to manage complex binary streams with a dedicated Audio Player Service. This project leverages a modern stack, including Angular v21, Node LTS, and Tailwind CSS v4, to provide a clean and professional developer experience. Whether you are building an AI assistant or a next-gen accessibility tool, these architectural patterns will help you master real-time AI speech integration.

| Start | End | Caption |
| --- | --- | --- |
| 00:00 | 00:24 | Intro and Background. |
| 00:24 | 03:09 | Demo Goals. |
| 03:09 | 04:42 | Sync Use Case Demo. |
| 04:42 | 07:04 | Streaming Use Case Demo. |
| 07:04 | 08:27 | Web Audio API Use Case Demo. |
| 08:27 | 10:14 | Backend Code Walkthrough (Part 1 - Firebase Cloud Functions text-to-speech). |
| 10:14 | 13:08 | Backend Code Walkthrough (Part 2 - NodeJS function sends TTS buffer). |
| 13:08 | 15:28 | Backend Code Walkthrough (Part 3 - NodeJS function streams TTS chunks). |
| 15:28 | 18:22 | Frontend Angular Code Walkthrough (Part 1 - Text to Speech and Oscure Fact components). |
| 18:22 | 22:49 | Frontend Angular Code Walkthrough (Part 2 - TTS operations in the Speech Service). |
| 22:49 | 26:54 | Frontend Angular Code Walkthrough (Part 3 - Audio Processing using the Web Audio API). |

#ai #angular #cloudfunctions #firebase #gemini #geminitts #webaudioapi #texttospeech #webdevelopment #genai

Github Repo: https://github.com/railsstudent/fireb...