models/Inworld/Inworld TTS 2

Inworld TTS 2

audio-tts

Inworld's most powerful and expressive text-to-speech model. Builds on TTS 1.5 with rich expressive speech, real-time latency, natural language steering (e.g. [whisper], [say excitedly]), and stronger multilingual support across 15 production languages plus 90+ experimental languages.

Inworld TTS 2 (inworld/tts-2) is a audio-tts model from Inworld, released 2026-05-05. Pricing via AIgateway: $0.035 per 1K chars. Call it via https://api.aigateway.sh/v1/audio/speech — set model="inworld/tts-2". Best for: Voiceovers, IVR, Audiobooks.

slug · inworld/tts-2provider · Inworldfamily · Inworld TTSreleased · 2026-05-05

Use this model

model: inworld/tts-2

curl https://api.aigateway.sh/v1/audio/speech \
  -H "Authorization: Bearer $AIGATEWAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"inworld/tts-2","voice":"alloy","input":"Hello, world."}'

curl https://api.aigateway.sh/v1/audio/speech \ -H "Authorization: Bearer $AIGATEWAY_API_KEY" \ -H "Content-Type: application/json" \ -d '{"model":"inworld/tts-2","voice":"alloy","input":"Hello world."}'

Capabilities

Strengths

Natural speech synthesis

Use cases

VoiceoversIVRAudiobooks

Pricing

Per 1K chars$0.035

You pay pass-through · 5% applied at credit top-up, not per-call.

Try in playground →Compare API reference See usage ranking →

Collections

More audio models →More from Inworld →Frontier models →Free-tier models →

API schema

Call Inworld TTS 2 from any OpenAI SDK

POST https://api.aigateway.sh/v1/audio/speech·Content-Type: application/json·Auth: Bearer sk-aig-...

Request body

json

{
  "model": "inworld/tts-2",
  "input": "Hello from AIgateway.",
  "voice": "alloy",
  "format": "mp3",        // mp3 | wav | flac | opus
  "speed": 1.0
}

Response

json

// Binary audio stream in the requested format (mp3 by default).
// Content-Type: audio/mpeg  (or audio/wav, audio/flac, audio/opus)
// Read the response body directly to a file.

Quickstart

from openai import OpenAI
client = OpenAI(base_url="https://api.aigateway.sh/v1", api_key="sk-aig-...")

r = client.audio.speech.create(model="inworld/tts-2", voice="alloy", input="Hello world.")
r.stream_to_file("out.mp3")

Errors

401authentication_errorInvalid or missing API key

402insufficient_creditsWallet empty (PAYG only)

404not_foundUnknown model or endpoint

429rate_limit_errorOver per-minute limit — see Retry-After header

500server_errorUpstream provider failed (retryable)

503service_unavailableUpstream saturated (retryable)

Full docs →API reference →OpenAPI spec →llms.txt →

Frequently asked questions

What is Inworld TTS 2?

How much does Inworld TTS 2 cost via AIgateway?

Pass-through pricing plus a 5% platform fee applied at top-up. See the pricing panel on this page for exact rates.

How do I call Inworld TTS 2 from my code?

Point the OpenAI SDK at https://api.aigateway.sh/v1 with your AIgateway key and set model to "inworld/tts-2". The request and response shapes match OpenAI exactly.

Does Inworld TTS 2 support streaming, tool calling, vision, and JSON mode?

Streaming — no. Tool calling — no. Vision — no. JSON mode — no. Prompt caching — no.

What are the best use cases for Inworld TTS 2?

Voiceovers, IVR, Audiobooks. Key strengths: Natural speech synthesis.

Can I bring my own Inworld API key (BYOK)?

Yes. Attach a Inworld key in your AIgateway dashboard and this model flips to pass-through — you pay Inworld directly and AIgateway waives the 5% platform fee on those calls.