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.
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.
Realtime TTS
Keep every user engaged with natural, realtime text-to-speech
#1 ranked TTS by real users on the Artificial Analysis Speech Arena. Sub-130ms first-chunk latency from $15 per million characters, up to 80% cheaper than comparable providers. Clone, design, steer, and stream natural responses.
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.
Live conversation
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.
Realtime 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.
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"
}
}
}'Use it with:+ many more
Top Models
#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
5%#7GPT 5.2
5%#8Kimi K2.5
3%#9MiniMax M2.5
3%#10Gemini 2.5 Flash Lite
2%Realtime 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.
Live transcription
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.
SOC2 Type II
Certified
HIPAA
Compliant
GDPR
Compliant
Voice AI, side-by-side comparison
Capability | Inworld | Google | ElevenLabs | Cartesia | OpenAI | Hume |
|---|---|---|---|---|---|---|
Voice quality (Artificial Analysis Speech Arena) | #1 | #2 | #3 | Not stated | #5 | Not stated |
Natural conversational delivery | Yes | Yes | Not stated | Not stated | Yes | Not stated |
Realtime latency | Yes | Not stated | Not stated | Yes | Not stated | Not stated |
Multi-turn aware speech synthesis | Yes | Not stated | Not stated | Not stated | Yes | Not stated |
Simple voice direction (inline tags) | Yes | Yes | Yes | Yes | Yes | Yes |
Advanced voice direction (free-form descriptions) | Yes | Not stated | Not stated | Not stated | Yes | Not stated |
Voice cloning | Yes | Not stated | Yes | Yes | Not stated | Yes |
Simple voice design (text-based) | Yes | Not stated | Yes | Not stated | Not stated | Not stated |
Advanced voice design | Yes | Not stated | Not stated | Not stated | Not stated | Not stated |
Crosslingual (single voice, over 100 languages) | Yes | Not stated | Yes | Not stated | Not stated | Not stated |
Voice profiling (understand user context) | Yes | Not stated | Not stated | Not stated | Not stated | Not stated |
Single customizable speech-to-speech API | Yes | Not stated | Not stated | Not stated | Not stated | Not stated |
User-aware LLM routing | Yes | Not stated | Not stated | Not stated | Not stated | Not stated |
Optimized alphanumeric support | Yes | Not stated | Yes | Not stated | Not stated | Not stated |
Verified May 2026 from public docs and the Artificial Analysis Speech Arena leaderboard. Based on the latest models from each provider.
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