Merge pull request #118 from second-state/alabulei1-patch-8

Add documentation for switching to Groq PlayAI TTS

Author: alabulei1

doc/dev/2025-12-15-echokit-day-18-groq-playai-tts.md

@@ -0,0 +1,76 @@
+---
+slug: echokit-30-days-day-18-groq-playai-tts
+title: "Day 18: Switching EchoKit to Groq PlayAI TTS | The First 30 Days with EchoKit"
+tags: [echokit30days, tts]
+---
+
+
+Over the past two weeks, we’ve built almost every core component of a voice AI agent on EchoKit:
+
+ASR to turn speech into text.
+LLMs to reason, chat, and call tools.
+[System prompts to shape personality](https://echokit.dev/docs/dev/echokit-30-days-day-14-personality).
+[MCP servers to let the agent take real actions](https://echokit.dev/docs/dev/echokit-30-days-day-15-mcp-web-search).
+[TTS to give EchoKit a voice](https://echokit.dev/docs/dev/echokit-30-days-day-17-elevenlabs).
+
+Today, we close the loop again — but this time, with a **new voice engine**.
+
+We’re switching EchoKit’s TTS backend to **[Groq’s PlayAI TTS](https://console.groq.com/docs/model/playai-tts)**.
+
+### Why change TTS?
+
+Text-to-speech is often treated as the “last step” in a voice pipeline, but in practice, it’s the part users feel the most.
+
+Latency, voice stability, and natural prosody directly affect whether a voice agent feels responsive or awkward. Since Groq already powers our ASR and LLM experiments with very low latency, it made sense to test their TTS offering as well.
+
+PlayAI TTS fits EchoKit’s design goals nicely:
+It’s fast, simple to integrate, and exposed through an OpenAI-compatible API.
+
+That means **no special SDK**, and no changes to EchoKit’s core architecture.
+
+### Switching EchoKit to Groq PlayAI TTS
+
+On EchoKit, swapping TTS providers is mostly a configuration change.
+
+To use Groq PlayAI TTS, we update the `tts` section in `config.toml` like this:
+
+```toml
+[tts]
+platform = "openai"
+url = "https://api.groq.com/openai/v1/audio/speech"
+model = "Playai-tts"
+api_key = "gsk_xxx"
+voice = "Fritz-PlayAI"
+```
+
+A few things worth calling out:
+
+The `platform` stays as `openai` because Groq exposes an OpenAI-compatible endpoint.
+We point the `url` directly to Groq’s audio speech API.
+The model is set to `Playai-tts`.
+Voices are selected via the `voice` field — here we’re using `Fritz-PlayAI`.
+
+Once this is in place, no other code changes are required.
+
+Restart the EchoKit server, reconnect the EchoKit device and the new server, and the agent speaks with a new voice.
+
+### The bigger picture
+
+Most importantly, switching different tts providers reinforces one of EchoKit’s core ideas:
+**every part of the voice pipeline should be swappable.**
+
+
+It’s about treating voice as a first-class system component — something you can experiment with, replace, and optimize just like models or prompts.
+
+EchoKit doesn’t lock you into one vendor or one voice.
+If tomorrow you want to try a different TTS engine, or even run one locally, the architecture already supports that.
+
+---
+
+Want to get your own EchoKit device and make it unique?
+
+* [EchoKit Box](https://echokit.dev/echokit_box.html)
+* [EchoKit DIY](https://echokit.dev/echokit_diy.html)
+
+Join the [EchoKit Discord](https://discord.gg/Fwe3zsT5g3) to share your welcome voices and see how others are personalizing their voice AI agents!
+