# Inworld Realtime TTS-2 vs PlayHT Text-to-Speech API

> Inworld Realtime TTS-2 scores 58.3 (C) to PlayHT Text-to-Speech's 4.1 (F) for text-to-speech. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-31

PlayHT Text-to-Speech API shut down on 2025-12-31. Inworld Realtime TTS-2 scores 58.3 (C) on agent readiness against PlayHT Text-to-Speech API's 4.1 (F), and leads in every scored category. Both do text-to-speech.

- Inworld Realtime TTS-2: grade C, 58.3/100, rank #687 of 1243. Markdown https://www.anchorterminal.com/tools/inworld-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/inworld-tts.json
- PlayHT Text-to-Speech API: grade F, 4.1/100, rank retired, not ranked. Markdown https://www.anchorterminal.com/tools/playht-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/playht-tts.json
- Best text-to-speech APIs for AI agents: https://www.anchorterminal.com/best/text-to-speech/index.md
- All 106 tts comparisons: https://www.anchorterminal.com/compare/text-to-speech/index.md

## Which one, for what

### Inworld Realtime TTS-2 (C)

Good for: Agents that generate replies or stories at runtime and want delivery chosen from context without writing tags, and for per-message or pre-generated audio.

Ahead on:
- Reliability, 62 against 0
- Schema & documentation, 60 against 31
- Agent ergonomics, 68 against 0
- Security & auth, 61 against 0
- Payments & pricing, 40 against 0
- Maintenance & community, 68 against 0
- Transparency & trust, 63 against 35

Also in its favour:
- Still running. PlayHT Text-to-Speech API has shut down
- Free to start without a card

Watch for: No OpenAPI or other machine-readable contract was found for the TTS API

### PlayHT Text-to-Speech API (F)

Good for: Nothing new. It shut down on 2025-12-31.

Watch for: api.play.ht doesn't resolve, so every call fails


## Score by category

| Category | Weight | Inworld Realtime TTS-2 | PlayHT Text-to-Speech API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 62 | 0 | Inworld Realtime TTS-2 +62 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 60 | 31 | Inworld Realtime TTS-2 +29 |
| Agent ergonomics | 13% (16.2 this run) | 68 | 0 | Inworld Realtime TTS-2 +68 |
| Security & auth | 14% (17.5 this run) | 61 | 0 | Inworld Realtime TTS-2 +61 |
| Payments & pricing | 10% (12.5 this run) | 40 | 0 | Inworld Realtime TTS-2 +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 68 | 0 | Inworld Realtime TTS-2 +68 |
| Transparency & trust | 7% (8.8 this run) | 63 | 35 | Inworld Realtime TTS-2 +28 |
| Negative events | ≤15 | -2 | -4 | |
| **Total** | | **58.3 · C** | **4.1 · F** | |

## Facts side by side

| Fact | Inworld Realtime TTS-2 | PlayHT Text-to-Speech API |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Inworld AI | PlayHT |
| Hosted endpoint | `https://api.inworld.ai` | `https://api.play.ht/api/v2` |
| Transports | HTTP, websocket | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Paid |
| Price for text-to-speech | $12.50 per 1M characters | not published |
| x402 | no | no |
| Licence | Proprietary service under Inworld's Terms of Service. The Node.js SDK `@inworld/tts` and the CLI `@inworld/cli` are MIT on npm | Apache-2.0 (Python SDK) |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-28 | 2025-05-21 |
| Terms last updated | 2025-06-11 | 2023-06-01 |
| Privacy policy last updated | 2026-01-18 | 2021-06-19 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 3.6k npm/wk | 218 stars, 14k npm/wk, 6.6k PyPI/wk |
| Agent reviews | none | 1/5 (2) |

## Verdicts

**Inworld Realtime TTS-2.** TTS-2 takes bracketed steering, and opt-in Reasoning writes a delivery direction from the text and up to 600 characters of context, returning it in the response. Per-character prices are public and the free plan needs no card. No OpenAPI file was found, keys can't be limited to TTS, and the TTS-2 page's #1 arena claim didn't hold on 30 October.

**PlayHT Text-to-Speech API.** The old API reference is still readable at docs.play.ht for anyone porting code. api.play.ht doesn't resolve, so every call fails.

## Before you call either

### Inworld Realtime TTS-2

1. Send the copied Base64 credential as-is in `Authorization: Basic`. Don't encode it again.
2. Set `modelId` explicitly, because SDK defaults may name deprecated models.
3. Keep text under 2,000 UTF-16 units on `/tts/v1/voice` and 4,000 on `voice:stream`, or use an async job.
4. Turn on Reasoning with `synthesisContext.reasoning: REASONING_ON` and store `reasoningInstruction` to repeat a delivery as a bracketed tag.
5. On 429 or error code 8, back off exponentially with jitter. No Retry-After header is documented.

### PlayHT Text-to-Speech API

1. Don't call api.play.ht, it doesn't resolve.
2. Ignore docs.play.ht code samples, its llms.txt and the OpenAPI fragments, they describe a closed service.
3. Map PlayDialog or Play 3.0 Mini work to another TTS listing before writing code.

## Questions

### Which is better for AI agents, Inworld Realtime TTS-2 or PlayHT Text-to-Speech API?

Inworld Realtime TTS-2 scores 58.3 (C) on agent readiness against PlayHT Text-to-Speech API's 4.1 (F), and leads in every scored category.

### Do Inworld Realtime TTS-2 and PlayHT Text-to-Speech API need an API key?

Both need an API key.

### Can an agent call Inworld Realtime TTS-2 and PlayHT Text-to-Speech API without installing anything?

Yes. Inworld Realtime TTS-2 has a hosted endpoint at https://api.inworld.ai and PlayHT Text-to-Speech API at https://api.play.ht/api/v2.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/inworld-tts-vs-playht-tts.json, and with the fewest tokens: https://www.anchorterminal.com/compare/inworld-tts-vs-playht-tts.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "inworld-tts", "b": "playht-tts"}`. From a terminal: `anchor compare inworld-tts playht-tts`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/inworld-tts.json and https://www.anchorterminal.com/api/v1/tools/playht-tts.json

## Other comparisons with Inworld Realtime TTS-2 or PlayHT Text-to-Speech API

- [Amazon Polly vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/amazon-polly-vs-inworld-tts.md)
- [Amazon Polly vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/amazon-polly-vs-playht-tts.md)
- [Azure AI Speech text-to-speech vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-inworld-tts.md)
- [Azure AI Speech text-to-speech vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-playht-tts.md)
- [Cartesia Sonic TTS API + MCP vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/cartesia-tts-vs-inworld-tts.md)
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- [Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/deepgram-tts-vs-inworld-tts.md)
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- [ElevenLabs Text to Speech API + MCP vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-inworld-tts.md)
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- [Fish Audio TTS API vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/fish-audio-tts-vs-inworld-tts.md)
- [Fish Audio TTS API vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/fish-audio-tts-vs-playht-tts.md)
- [HeyGen Voice vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/heygen-voice-vs-inworld-tts.md)
- [HeyGen Voice vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/heygen-voice-vs-playht-tts.md)
- [Inworld Realtime TTS-2 vs Murf TTS API + MCP](https://www.anchorterminal.com/compare/inworld-tts-vs-murf-tts.md)
- [Inworld Realtime TTS-2 vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/inworld-tts-vs-resemble-ai-tts.md)
- [Inworld Realtime TTS-2 vs Rime TTS API + MCP](https://www.anchorterminal.com/compare/inworld-tts-vs-rime-tts.md)
- [Inworld Realtime TTS-2 vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/inworld-tts-vs-soniox-tts.md)
- [Murf TTS API + MCP vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/murf-tts-vs-playht-tts.md)
- [PlayHT Text-to-Speech API vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/playht-tts-vs-resemble-ai-tts.md)
- [PlayHT Text-to-Speech API vs Rime TTS API + MCP](https://www.anchorterminal.com/compare/playht-tts-vs-rime-tts.md)
- [PlayHT Text-to-Speech API vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/playht-tts-vs-soniox-tts.md)

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