API cheat sheet

Base URLs, bearer authentication, and runnable examples for Rime’s HTTP, WebSocket, voice, vocabulary, and text-normalization endpoints.

Create a key on the API Tokens page before running the authenticated examples below.

Hosts and authentication

What	Where
REST API (TTS, voices, coverage)	https://users.rime.ai
WebSocket API	wss://users-ws.rime.ai
Text normalization	https://optimize.rime.ai
Docs (this site, plus /llms.txt and per-page .md exports)	https://docs.rime.ai

• Send TTS requests to users.rime.ai, not api.rime.ai. The latter serves internal infrastructure and returns 404 for TTS requests.
• Authenticate with Authorization: Bearer YOUR_API_KEY. On WebSocket connections, send the same value as a connection header.
• Keep the key on a server. Browser WebSocket objects cannot set the required header, so browser applications need a server-side bridge.
• Rime does not publish an npm or PyPI SDK. Similarly named registry packages are unrelated third-party projects.

Synthesize speech (HTTP)

POST /v1/rime-tts returns audio bytes in the format named by your Accept header (audio/mpeg, audio/wav, audio/webm;codecs=opus, audio/ogg;codecs=opus, audio/L16, audio/PCMU):

curl -X POST https://users.rime.ai/v1/rime-tts \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'Content-Type: application/json' \
  -H 'Accept: audio/mpeg' \
  --output hello.mp3 \
  -d '{"text": "Hello from Rime.", "speaker": "astra", "modelId": "coda"}'

Full parameters and streaming variants: Coda HTTP reference · Streaming guide

Stream speech (WebSocket /ws3)

Synthesis arguments go in the query string; auth goes in the connection header. Send {"text": ...} messages (buffered by sentence by default) and operations ({"operation": "flush" | "clear" | "eos"}); receive JSON events: chunk (base64 audio), timestamps (word-level), done, error.

import asyncio, base64, json, os
import websockets  # pip install websockets

async def main():
    url = "wss://users-ws.rime.ai/ws3?speaker=astra&modelId=coda&audioFormat=mp3"
    headers = {"Authorization": f"Bearer {os.environ['RIME_API_KEY']}"}
    async with websockets.connect(url, additional_headers=headers) as ws:
        await ws.send(json.dumps({"text": "Hello from Rime over WebSockets."}))
        await ws.send(json.dumps({"operation": "eos"}))  # synthesize what's buffered, then close
        audio = b""
        async for raw in ws:
            event = json.loads(raw)
            if event["type"] == "chunk":
                audio += base64.b64decode(event["data"])
            elif event["type"] == "timestamps":
                print("words:", event["word_timestamps"]["words"])
            elif event["type"] == "done":
                break
    with open("output.mp3", "wb") as f:
        f.write(audio)
    print(f"saved {len(audio)} bytes to output.mp3")

asyncio.run(main())

Set modelId explicitly on /ws3. Without it, requests are served by the Mist v3 backend, and speakers outside the Mist v3 catalog fail with a “Speaker not found” error. Message schemas: Coda WebSocket reference · Buffering control: Segmentation · Web-app bridge pattern: Next.js voice-agent guide

List voices

Both voice endpoints are public; no API key required.

# Voice names, keyed by modelId then ISO 639-2 language code
curl https://users.rime.ai/data/voices/all-v2.json

# Full metadata per voice (gender, age, dialect, language, flagship flag, …)
curl https://users.rime.ai/data/voices/voice_details.json

Choosing a voice: Voices guide · Reference: List All Voices · List Voice Details

Check vocabulary coverage (/oov)

Returns the input words that are not in Rime’s pronunciation dictionary:

curl -X POST https://users.rime.ai/oov \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"text": "hello kubectl blorbify"}'
# → ["kubectl","blorbify"]

Out-of-dictionary words still get a best-effort pronunciation; to control them, see Custom pronunciation. Reference: Vocabulary Coverage

Normalize text (/textnorm)

Preview exactly how numbers, dates, and phone numbers will be spoken. Note the host: optimize.rime.ai.

curl -X POST https://optimize.rime.ai/textnorm \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"text": "Call 1-800-444-4141 on 3/4/2026"}'
# → {"normalized":"Call one, eight hundred, four four four, four one four one on march fourth twenty twenty six"}

Guide: Text normalization · Reference: Text Normalization

Common parameters

Parameter	Values	Notes
speaker	See voices	Required. Must match the model and language.
modelId	coda (flagship), mistv3	Set it explicitly. Without one, /ws3 serves only the Mist v3 voice catalog.
text	string	Up to 1,000 characters per request (HTTP returns 400 “text is too long” beyond that).
lang	en/eng, es/spa, fr/fra, pt/por, de/ger, ja/jpn, ar/ara, hi/hin	Must match the speaker’s language.
audioFormat (WS)	mp3, mulaw, pcm	HTTP uses the Accept header instead.
segment (WS)	bySentence (default), immediate, never	When synthesis triggers; see Segmentation.
samplingRate	8000–96000, default 24000	Values above 24000 are upsampling.

Where to go deeper

• API reference index: every endpoint across every model
• WebSocket API overview: endpoint comparison, timestamps, interruption handling
• Build a voice agent: complete apps in Next.js, Vite, Express, plain Node, and FastAPI
• Rime CLI and the hosted MCP server: tooling around this same API