From Piper to Polly: How I Built a Production-Ready Text-to-Speech API (and Everything That Broke Along the Way)

A walkthrough of building a voice AI backend — through three TTS providers, a chunking problem, Redis caching, distributed locks, and a thundering herd. The Idea I wanted to read long articles without staring at a screen. The concept was simple: paste an article, get back an MP3. Building it turned out to be an education in the real-world constraints of TTS APIs — character limits, latency, cost, and what happens when 50 users click Play on the same article at the same moment. Here's the full jo