diff --git a/docs-site/docs/configure/tts-provider-guides/other.md b/docs-site/docs/configure/tts-provider-guides/other.md
index 4e3aafc..1d247a0 100644
--- a/docs-site/docs/configure/tts-provider-guides/other.md
+++ b/docs-site/docs/configure/tts-provider-guides/other.md
@@ -6,12 +6,14 @@ Use any OpenAI-compatible TTS service with OpenReader, including self-hosted ser
 
 ## Requirements
 
-Your service must expose these endpoints:
+Your service only needs an OpenAI-compatible speech endpoint:
 
-- `GET /v1/audio/voices`
-- `POST /v1/audio/speech`
+- `POST /v1/audio/speech` — **required**.
+- Voice listing is **optional** and auto-discovered from `/v1/audio/voices`, `/v1/voices`, or `/v1/styles`; OpenReader falls back to default voices if none are available.
 
-Known compatible implementations: [Kokoro-FastAPI](./kokoro-fastapi), [KittenTTS-FastAPI](./kitten-tts-fastapi), [Orpheus-FastAPI](./orpheus-fastapi).
+The endpoint may return `mp3`, `wav`, `ogg`, or `flac` — OpenReader normalizes non-mp3 audio to mp3 automatically. An API key is optional.
+
+Known compatible implementations: [Kokoro-FastAPI](./kokoro-fastapi), [KittenTTS-FastAPI](./kitten-tts-fastapi), [Orpheus-FastAPI](./orpheus-fastapi), [Supertonic](./supertonic).
 
 ## Setup
 
@@ -44,7 +46,7 @@ See [TTS Providers](../tts-providers) for admin-shared vs per-user behavior.
 
 ## Troubleshooting
 
-If voices don't load, check that `/v1/audio/voices` is reachable from the server and returns a valid response shape.
+If voices don't load, confirm the server is reachable from the Next.js runtime and that at least one of `/v1/audio/voices`, `/v1/voices`, or `/v1/styles` returns a valid response. If none do, OpenReader falls back to default voices — synthesis still works as long as `POST /v1/audio/speech` succeeds.
 
 ## References
 
diff --git a/docs-site/docs/configure/tts-providers.md b/docs-site/docs/configure/tts-providers.md
index 376e1dc..b0e0565 100644
--- a/docs-site/docs/configure/tts-providers.md
+++ b/docs-site/docs/configure/tts-providers.md
@@ -31,10 +31,12 @@ For `OpenAI`, `DeepInfra`, and `Replicate` you only need to supply an API key. F
 
 ## Custom provider requirements
 
-Self-hosted or custom providers must expose OpenAI-compatible audio endpoints:
+Self-hosted or custom providers only need an OpenAI-compatible speech endpoint:
 
-- `GET /v1/audio/voices`
-- `POST /v1/audio/speech`
+- `POST /v1/audio/speech` — **required**.
+- Voice listing is **optional** and auto-discovered: OpenReader probes `/v1/audio/voices`, `/v1/voices`, then `/v1/styles`, and falls back to sensible default voices if none respond.
+
+The speech endpoint may return any common audio format — `mp3`, `wav`, `ogg`, or `flac`. OpenReader detects the format and transcodes non-mp3 audio to mp3 automatically, so your server does not need to honor `response_format: mp3`. An API key is optional; keyless servers work.
 
 :::warning TTS requests are server-side
 TTS requests originate from the **Next.js server**, not the browser. `API_BASE` must be reachable from the server runtime. In Docker, use container names or `host.docker.internal` rather than `localhost`.