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Overview

Rime AI provides two TTS service implementations: RimeTTSService (WebSocket-based) with word-level timing and interruption support, and RimeHttpTTSService (HTTP-based) for simpler use cases. RimeTTSService is recommended for real-time interactive applications.

Rime TTS API Reference

Pipecat’s API methods for Rime TTS integration

Example Implementation

Complete example with word timestamps

Rime Documentation

Official Rime WebSocket and HTTP API documentation

Voice Models

Explore available voice models and features

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Installation

To use Rime services, install the required dependencies: 
pip install "pipecat-ai[rime]"

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Prerequisites

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Rime Account Setup

Before using Rime TTS services, you need:
  1. Rime Account: Sign up at Rime AI
  2. API Key: Generate an API key from your account dashboard
  3. Voice Selection: Choose from available voice models

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Required Environment Variables

  • RIME_API_KEY: Your Rime API key for authentication

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Customizing Speech

RimeTTSService provides a set of helper methods for implementing Rime-specific customizations, meant to be used as part of text transformers. These include methods for spelling out text, adjusting speech rate, and modifying pitch. See the Text Transformers for TTS section in the Text-to-Speech guide for usage examples.

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SPELL(text: str) -> str:

Implements Rime’s spell function to spell out text character by character. 
# Text transformers for TTS
# This will insert Rime's spell tags around the provided text.
async def spell_out_text(text: str, type: str) -> str:
    return RimeTTSService.SPELL(text)

tts = RimeTTSService(
    api_key=os.getenv("RIME_API_KEY"),
    text_transforms=[{
        "phone_number": spell_out_text,
    }],
)

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PAUSE_TAG(seconds: float) -> str:

Implements Rime’s custom pause functionality to generate a properly formatted pause tag you can insert into the text. 
# Text transformers for TTS
# This will insert a one second pause after questions.
async def pause_after_questions(text: str, type: str) -> str:
    if text.endswith("?"):
        return f"{text}{RimeTTSService.PAUSE_TAG(1.0)}"
    return text

tts = RimeTTSService(
    api_key=os.getenv("RIME_API_KEY"),
    text_transforms=[{
        "sentence": pause_after_questions, # Only apply to sentence aggregations
    }],
)

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PRONOUNCE(self, text: str, word: str, phoneme: str) -> str:

Convenience method to support Rime’s custom pronunciations feature. It takes a word and its desired phoneme representation, returning the text with the provided word replaced by the appropriate phoneme tag. 
# Text transformers for TTS
# This will a phoneme in place of the word "potato" to define how it
# should be pronounced.
async def maybe_say_potato_all_fancylike(text: str, type: str) -> str:
    if using_fancy_voice:
        return RimeTTSService.PRONOUNCE(text, "potato", "potato")
    else:
        return RimeTTSService.PRONOUNCE(text, "potato", "poteto")

tts = RimeTTSService(
    api_key=os.getenv("RIME_API_KEY"),
    text_transforms=[{
        "*": maybe_say_potato_all_fancylike, # Apply to all text
    }],
)

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INLINE_SPEED(self, text: str, speed: float) -> str:

A convenience method to support Rime’s inline speed adjustment feature. It will wrap the provided text in the [] tags and add the provided speed to the inlineSpeedAlpha field in the request metadata. 
# Text transformers for TTS
# This will make the word slow always be spoken more slowly.
async def slow_down_slow_words(text: str, type: str) -> str:
    return text.replace(
        "slow",
        RimeTTSService.INLINE_SPEED("slow", speed=0.5)
    )

tts = RimeTTSService(
    api_key=os.getenv("RIME_API_KEY"),
    text_transforms=[{
        "*": slow_down_slow_words, # Apply to all text
    }],
)