The #1 ranked,

most natural voice AI

Make every user feel understood with the top-ranked text-to-speech, speech-to-speech and LLM routing. Production-grade APIs built for developers.

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Status reached 1M DAUs in 19 days.

OtherHalf powers voice-first companions at scale.

Ongoing, personal, emotionally engaging AI interaction. Build for relationship-building, emotional connection, and entertainment at scale.

Inworld TTS

Keep every user engaged with natural, realtime text-to-speech

#1 ranked TTS with human-like expression and realtime sub-200ms latency that feels like a real conversation, at a fraction of the cost of other providers. Create voices with cloning or text-based voice design. Stream for fully natural conversations.

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Inworld Realtime API

Controllable speech-to-speech that understands, reasons, and interacts

End-to-end speech-to-speech with custom voices and tool calling. Fully customizable. Optimize for cost, latency, or what your users care about most.

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Live conversation

User

turn_detection semantic_vadeagerness mediumemotion stressedage young

I've been feeling really overwhelmed lately. I don't even know where to start.

Companion

voice Lunaoutput_modalities text, audio

That's completely valid. Let's take a breath together first, then we can talk through what's on your mind — one thing at a time.

Full duplex, low-latency streamingFull-duplex audio streaming over a single WebSocket or WebRTC connection.

Intelligent turn takingContext-aware turn detection with adjustable eagerness.

Function callingRegister tools mid-session. The assistant calls your functions without breaking audio.

Provider agnosticRoute to the model that fits your latency, cost, or quality requirements, and swap it out at any time.

Dynamic context managementCreate, retrieve, delete, or truncate conversation items mid-session to control context length and token cost.

Conversational intelligenceUse acoustic and metadata signals to condition what is said, when it is said, and how it is expressed.

Inworld Router

Reason in realtime. Route to the best model and tools for every user and context

One API that intelligently routes requests across OpenAI, Anthropic, Google, and 200+ models. Built-in analytics to ensure the metrics you care about improve. No latency added. Built-in failover, A/B testing, and intelligent model selection with no code changes required.

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curl 'https://api.inworld.ai/v1/chat/completions' \
  -H "Content-Type: application/json" \
  -H "Authorization: Basic $INWORLD_API_KEY" \
  -d '{

    "model": "inworld/user-aware",

    "messages": [{"role": "user", "content": "Hello"}],
    "extra_body": {
        "metadata": {
            "language": "es",
            "country": "MX",
            "plan": "free"
        }
    }
  }'

curl 'https://api.inworld.ai/v1/chat/completions' \
  -H "Content-Type: application/json" \
  -H "Authorization: Basic $INWORLD_API_KEY" \
  -d '{

    "model": "inworld/context-aware",

    "messages": [
        {"role": "system", "content": "You are a support agent."},
        {"role": "user", "content": "My order never arrived"}
    ],
    "extra_body": {
        "metadata": {
            "intent": "complaint",
            "emotion": "frustrated",
            "session_turns": 4
        }
    }
  }'

Use it with:

+ many more

Top Models

Most popular models by % of Router traffic

#1Gemini 3 Flash

16%

#2Qwen3 Max

14%

#3Claude Sonnet 4.6

12%

#4Claude Opus 4.6

12%

#5Grok 4.1 Fast

10%

#6Gemini 2.5 Flash

#7GPT 5.2

#8Kimi K2.5

#9MiniMax M2.5

#10Gemini 2.5 Flash Lite

Inworld STT

Speech-to-text that truly understands your users in realtime

Understand your users and their context in realtime with built-in voice profiling, along with state-of-the-art latency and accuracy.

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Live transcription

Customer

lang en-USage adultemotion frustratedstyle shouting

I've been looking all through my account and can't figure out why I was charged twice on order CX-204.

Agent

lang en-USage adultemotion calmstyle reassuring

I can see the duplicate charge on your account. I'm processing a refund right now. Sorry for the frustration.

Realtime streamingRealtime, bidirectional streaming over WebSocket for live audio, or synchronous transcription for complete audio files.

Voice profiling: emotion, age, accent, pitch & styleExtract five real-time signals per audio chunk to understand who is speaking and how they feel.

Semantic & acoustic VADAutomatically detect when speech starts and stops. Enable natural speech patterns.

Unified multi-provider APIA single integration point for industry-leading, high-accuracy transcription providers, with consistent authentication, request formatting, and response handling.

High accuracy & custom vocabularyTranscribe audio with industry-leading accuracy. Add domain-specific terms, product names, and specialized vocabulary to boost recognition further.

Word-level timestamps & diarizationPer-word timing for subtitles and search. Label speakers in multi-party conversations.

Security

Build with confidence on secure AI infrastructure

Enterprise-grade security and compliance built into our AI platform. Built on a zero-trust framework with continuous monitoring, providing a secure foundation for teams building the next generation of AI.

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