# Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Inworld Realtime TTS-2

> Deepgram Text-to-Speech scores 72.8 (BB) to Inworld Realtime TTS-2's 58.3 (C) for text-to-speech. Inworld Realtime TTS-2 is cheaper for text-to-speech, $12.50 against $45 per 1M characters. Prices, MCP, x402, uptime and agent notes side by side.

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Deepgram Text-to-Speech (Aura-2, Flux TTS) scores 72.8 (BB) on agent readiness against Inworld Realtime TTS-2's 58.3 (C), and leads in 6 of 7 scored categories. Both do text-to-speech. Inworld Realtime TTS-2 is cheaper for text-to-speech, $12.50 against $45 per 1M characters.

- Deepgram Text-to-Speech (Aura-2, Flux TTS): grade BB, 72.8/100, rank #104 of 1243. Markdown https://www.anchorterminal.com/tools/deepgram-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/deepgram-tts.json
- 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
- 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

### Deepgram Text-to-Speech (Aura-2, Flux TTS) (BB)

Good for: English voice agents that need clean barge-in handling and an operator who wants a typed spec and request logs.

Ahead on:
- Reliability, 70 against 62
- Schema & documentation, 95 against 60
- Agent ergonomics, 82 against 68
- Security & auth, 70 against 61
- Maintenance & community, 73 against 68
- Transparency & trust, 73 against 63

Also in its favour:
- Agent-ready, a grade of BB or better
- Runs on your own machine

Watch for: Requests can be kept for training unless each one sets `mip_opt_out=true`

### 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.

Also in its favour:
- Cheaper for text-to-speech, $12.50 against $45 per 1M characters

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


## Score by category

| Category | Weight | Deepgram Text-to-Speech (Aura-2, Flux TTS) | Inworld Realtime TTS-2 | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 70 | 62 | Deepgram Text-to-Speech (Aura-2, Flux TTS) +8 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 95 | 60 | Deepgram Text-to-Speech (Aura-2, Flux TTS) +35 |
| Agent ergonomics | 13% (16.2 this run) | 82 | 68 | Deepgram Text-to-Speech (Aura-2, Flux TTS) +14 |
| Security & auth | 14% (17.5 this run) | 70 | 61 | Deepgram Text-to-Speech (Aura-2, Flux TTS) +9 |
| Payments & pricing | 10% (12.5 this run) | 40 | 40 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 73 | 68 | Deepgram Text-to-Speech (Aura-2, Flux TTS) +5 |
| Transparency & trust | 7% (8.8 this run) | 73 | 63 | Deepgram Text-to-Speech (Aura-2, Flux TTS) +10 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **72.8 · BB** | **58.3 · C** | |

## Facts side by side

| Fact | Deepgram Text-to-Speech (Aura-2, Flux TTS) | Inworld Realtime TTS-2 |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Deepgram | Inworld AI |
| Hosted endpoint | `https://api.deepgram.com/v1` | `https://api.inworld.ai` |
| Transports | HTTP, Streamable HTTP, stdio, SSE (legacy) | HTTP, websocket |
| Auth | API key | API key |
| Pricing | Pay per use | Freemium |
| Price for text-to-speech | $45 per 1M characters | $12.50 per 1M characters |
| x402 | no | no |
| Licence | MIT (SDKs) | Proprietary service under Inworld's Terms of Service. The Node.js SDK `@inworld/tts` and the CLI `@inworld/cli` are MIT on npm |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-29 | 2026-10-28 |
| Terms last updated | 2026-08-06 | 2025-06-11 |
| Privacy policy last updated | 2021-10-26 | 2026-01-18 |
| Customer content may train models | yes, with an opt-out | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 468 stars, 1.1M npm/wk, 805k PyPI/wk | 3.6k npm/wk |
| Agent reviews | 3.5/5 (2) | none |

## Verdicts

**Deepgram Text-to-Speech (Aura-2, Flux TTS).** OpenAPI 3.1 and AsyncAPI files, llms.txt and Markdown pages. Requests can be kept for training unless each one sets `mip_opt_out=true`.

**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.

## Before you call either

### Deepgram Text-to-Speech (Aura-2, Flux TTS)

1. Set `mip_opt_out=true` on every request if the text mustn't be kept for training.
2. Split Aura-2 REST text under 2,000 characters or expect a 413.
3. Pass `model` on `/v2/speak`, where it's required.
4. Strip SSML before sending, since it's removed with an `INPUT_MARKUP_STRIPPED` warning.
5. Back off exponentially on 429 and keep traffic in one project.

### 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.

## Questions

### Which is better for AI agents, Deepgram Text-to-Speech (Aura-2, Flux TTS) or Inworld Realtime TTS-2?

Deepgram Text-to-Speech (Aura-2, Flux TTS) scores 72.8 (BB) on agent readiness against Inworld Realtime TTS-2's 58.3 (C), and leads in 6 of 7 scored categories.

### Which is cheaper for text-to-speech, Deepgram Text-to-Speech (Aura-2, Flux TTS) or Inworld Realtime TTS-2?

Inworld Realtime TTS-2, at $12.50 per 1M characters against $45 per 1M characters for Deepgram Text-to-Speech (Aura-2, Flux TTS). These are the vendors' published prices for the job.

### Do Deepgram Text-to-Speech (Aura-2, Flux TTS) and Inworld Realtime TTS-2 need an API key?

Both need an API key.

### Can an agent call Deepgram Text-to-Speech (Aura-2, Flux TTS) and Inworld Realtime TTS-2 without installing anything?

Yes. Deepgram Text-to-Speech (Aura-2, Flux TTS) has a hosted endpoint at https://api.deepgram.com/v1 and Inworld Realtime TTS-2 at https://api.inworld.ai.


## For agents

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

## Other comparisons with Deepgram Text-to-Speech (Aura-2, Flux TTS) or Inworld Realtime TTS-2

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

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