# Google Cloud Text-to-Speech vs HeyGen Voice

> HeyGen Voice scores 73.6 (BB) to Google Cloud Text-to-Speech's 66.9 (B) for text-to-speech. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/google-cloud-tts-vs-heygen-voice
- Markdown: https://www.anchorterminal.com/compare/google-cloud-tts-vs-heygen-voice.md (~5,450 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

HeyGen Voice scores 73.6 (BB) on agent readiness against Google Cloud Text-to-Speech's 66.9 (B), and leads in 4 of 7 scored categories. Google Cloud Text-to-Speech leads on reliability, security & auth and transparency & trust. Both do text-to-speech.

- Google Cloud Text-to-Speech: grade B, 66.9/100, rank #351 of 1510. Markdown https://www.anchorterminal.com/tools/google-cloud-tts.md · JSON https://www.anchorterminal.com/api/v1/tools/google-cloud-tts.json
- HeyGen Voice: grade BB, 73.6/100, rank #103 of 1510. Markdown https://www.anchorterminal.com/tools/heygen-voice.md · JSON https://www.anchorterminal.com/api/v1/tools/heygen-voice.json
- Best text-to-speech APIs for AI agents: https://www.anchorterminal.com/best/text-to-speech/index.md
- All 148 tts comparisons: https://www.anchorterminal.com/compare/text-to-speech/index.md

## Which one, for what

### Google Cloud Text-to-Speech (B)

Good for: Teams already on Google Cloud wanting many languages, SSML and an SLA.

Ahead on:
- Reliability, 85 against 75
- Security & auth, 80 against 69
- Transparency & trust, 87 against 66

Watch for: No release note since 30 December 2025, though a Gemini 3.1 TTS preview model is listed

### HeyGen Voice (BB)

Good for: Speech in a voice cloned from one short recording, for agents that already make HeyGen videos or need a cloned narrator with streaming and timestamps.

Ahead on:
- Schema & documentation, 97 against 80
- Agent ergonomics, 88 against 65
- Payments & pricing, 40 against 20
- Maintenance & community, 65 against 25

Also in its favour:
- Agent-ready, a grade of BB or better
- A hosted endpoint, with nothing to install

Watch for: 30 requests a minute per workspace member on the speech endpoints by default, and Turbo Free's shared capacity can return 429 below that


## Why the edge

### Maintenance & community: HeyGen Voice +40

- Google Cloud Text-to-Speech (25): Read as a model. The newest release note is still 30 December 2025 (Chirp 3 HD in yue-HK), 311 days ago, and `gemini-3.1-flash-tts-preview` appears on the Gemini-TTS page with no dated note (0). In the 90 days from 8 August the Python client shipped 2.38.0 on 1 October, whose only change declares Python 3.15 support, which counts half and can't set the recency line (0). Release notes, a public issue tracker and paid support (10 of 15). Official client libraries, Python at 2.38.0 and Node at 7.2.0 (10 of 15). Package CI not checked (5 of 10). Total 25.
- HeyGen Voice (65): Read as a model. The changelog's newest voice entry, speech to speech, is in the RSS feed on 20 October 2026 (30). Seven voice entries between 9 and 20 October alone, instant voices, Turbo, public voices with timestamps, previews, voices from an image, professional voices without a language and speech to speech, and dated sunsets elsewhere in the API, v1 and v2 on 31 October 2026, announced in April (20). Public changelog with RSS and a developer Discord. Answers were not sampled (10 of 15). No official SDK. HeyGen ships a CLI and agent skills (5 of 15). No package health record was read (0). Total 65.

### Agent ergonomics: HeyGen Voice +23

- Google Cloud Text-to-Speech (65): API reading of the checklist. Audio returns Base64 in JSON or streams over gRPC, with encoding, sample rate and timepoints selectable (15 of 25). `voices.list` filters by language code with no paging, and operations list with page tokens (15 of 20). Standard gRPC status codes with messages, generic rather than TTS-specific (15 of 20). Synthesis is stateless and long audio runs as an operation, with no idempotency key (10 of 20). A first call needs a project, billing, OAuth credentials and a voice, and Cloud Storage for long audio. Official client libraries in many languages, of which Python and Node were checked (10 of 15). Total 65.
- HeyGen Voice (88): API reading of the checklist. The completed response is a URL and a duration, streaming returns WAV parts as they are made, and timestamps come only when asked. Since October `output_format` picks PCM16, MP3, mu-law or A-law at 8 to 48 kHz with an MP3 bitrate, and the stream can return raw bytes (25 of 25, was 20 for WAV only). Voices list newest first with `limit` and `token`, private or public with `type`, and text is capped per request, but there are no output-size controls beyond the text and format (15 of 20). Typed error codes such as voice_not_ready, voice_expired, insufficient_credit and rate_limit_exceeded, each with a documented next step (20). Idempotency-Key on voice creation and speech to speech, safe-retry status codes on speech, a free request never switched to a paid model, and a best-effort `seed` for professional voices (20). Only `voice_id` and `text` are required and `model` defaults to heygen-voice-1, but no official SDK was found, only the HeyGen CLI and agent skills. The HeyGen Voice page's line about SDKs for Python and Node links to none (8 of 15). Total 88.

### Transparency & trust: Google Cloud Text-to-Speech +21

- Google Cloud Text-to-Speech (87): Closed service under the Google Cloud terms, with Apache-2.0 clients (15). The data logging page, the terms and the privacy notice agree that TTS text and audio aren't logged, and a DPA and sub-processor list exist, as read for google-speech-to-text (25 of 30). Release notes mark preview and GA, and the Cloud terms carry notice before a GA capability is discontinued, but Gemini-TTS is moving to the Agent Platform API with no dated notice for the Cloud TTS models (15 of 20). Regional endpoints (global, us, eu and others) and a public sub-processor list (20). Total 75.
- HeyGen Voice (66): Closed service with terms dated 23 July 2026, per the 10 October check. Paid plans own their output, and free-plan output is limited to non-commercial use (15). Privacy policy, terms and security page agree that non-enterprise input can train models with an opt-out by email, and differ on the entity name (HeyGen Technology Inc. and HeyGen, Inc.). No retention period for voice or speech data (12 of 30). Dated deprecation notices in the changelog, such as the v1 and v2 sunset on 31 October 2026, and an end date for Turbo Free with a promise of notice before it changes, but no notice yet for this model (15 of 20). Subprocessors are listed on the security portal, which was not read, and the privacy policy says data may be processed in the United States (10 of 20). Total 52.

### Payments & pricing: HeyGen Voice +20

- Google Cloud Text-to-Speech (20): No x402, MPP or L402 (0). Per-character and per-token prices for every voice family published without a login (20). Monthly free characters (1 million for Chirp 3 HD, 4 million for Standard and WaveNet) need billing enabled, which needs a card (0). A person creates a project and billing account in a browser (0). Total 20.
- HeyGen Voice (40): No x402, MPP or L402 in the llms.txt, the OpenAPI file or the voice pages (0). The HeyGen Voice page publishes API speech at $30 per million characters on heygen-voice-1, $15 on Turbo and speech to speech at $0.12 a minute, without a login (20). `heygen-voice-1-turbo-free` is free until 30 November 2026 with a free API key and no credit balance, for public and instant voices, under shared capacity. Neither the docs nor the HeyGen Voice page say whether the free key needs a card at sign-up, and "no credit balance" isn't the same statement. HeyGen's pricing FAQ says the web Free plan needs no card, but doesn't say that covers API keys, and the API dashboard's host couldn't be read. So half, the reading listings with unstated card terms get (anthropic-api, zep, and fish-audio-voice-cloning for its free model to the same date), until it ends (10). Stripe Projects lists heygen/api, which lets an agent create the account and receive a key through the operator's Stripe login and saved payment method. A person still has to log in to Stripe once (10). 0+20+10+10 = 40.

### Schema & documentation: HeyGen Voice +17

- Google Cloud Text-to-Speech (80): Discovery document revision 20260827 with typed methods and 26 schemas, and protocol buffers for gRPC (25). No llms.txt found (0). The Chirp 3 HD and Gemini-TTS pages say which voices suit which use and list formats and limits, but the reference doesn't say when to choose streaming or long audio (15 of 20). Typed messages with enums for encoding and gender and required fields (15). Samples in several languages, standard status codes with little method-specific error detail (10 of 15). Versioned v1 and v1beta1 with dated release notes (15). Total 80.
- HeyGen Voice (97): OpenAPI 3.1 file at developers.heygen.com/openapi/external-api.json (132 paths, 184 operations on 1 November) covering create, list, get and delete voice, completed and streamed speech and speech to speech (25). llms.txt with a Markdown twin of every page (10). Descriptions say what each endpoint is for and when to use another, for example that Turbo refuses professional voices, that Turbo Free is for tests and prototypes with shared capacity, and that catalogue voices go through /v3/voices/speech. Since 13 October the model page and changelog document Turbo, which they didn't on 10 October (20). Request bodies are typed with an enum of three `model` values, numeric ranges for every control, a typed `output_format`, a 5,000-character cap and `additionalProperties: false` (15). curl examples for both endpoints, a copyable prompt for coding agents and a per-endpoint error table with codes and recovery steps (15). Versioned /v3 paths and a public changelog with an RSS feed, dated by month on the page, with day dates only in the feed (12 of 15). Total 97.

### Security & auth: Google Cloud Text-to-Speech +11

- Google Cloud Text-to-Speech (80): Model reading of the checklist, with training and retention in place of the least-privilege and injection lines. OAuth 2.0 with service accounts and IAM roles per project (30). The discovery document lists `access_token`, `oauth_token` and `key` as query parameters, so 10 off, as every Google API listing in this run (20 of 30). The data logging page says Google doesn't log any customer Cloud TTS text or audio (20). The service is stateless and keeps no content (15). Because it is stateless, Data Access audit logs don't apply, leaving admin activity only (5 of 15). Valid security.txt, Google's vulnerability reward programme, SOC 2 and ISO 27001 and public Cloud security bulletins, as on google-speech-to-text (20). Total 80.
- HeyGen Voice (69): Model reading of the checklist, with training and retention in place of least-privilege and injection lines. API keys can be restricted to resource read and write scopes, a key without the scope gets 403 insufficient_api_key_scope, `GET /v3/api_keys/self` reports a key's scope mode, and the docs cover rotation (30). The privacy policy (11 August 2026) and the terms (23 July 2026) allow training on user input, with an opt-out by email, and the security page excludes enterprise data by default, per the 10 October check, not re-read on 1 November (10). No retention period for voices or speech was found, deleted data stays in backups for 60 days, and voices can be deleted through the API (5). Each response carries an X-Request-Id used in usage and billing records, and `end_user_id` attributes usage per end user. Audit logs of user and admin actions are for enterprise customers (10 of 15). A valid security.txt (expires 31 December 2026, re-read 1 November), a disclosure policy with safe harbour, SOC 2 Type II stated on the security page with reports on request, and no bug bounty. The report was not read, so the certification counts as a vendor claim (14 of 20). Total 69.

## Score by category

| Category | Weight | Google Cloud Text-to-Speech | HeyGen Voice | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 85 | 75 | Google Cloud Text-to-Speech +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 80 | 97 | HeyGen Voice +17 |
| Agent ergonomics | 13% (16.2 this run) | 65 | 88 | HeyGen Voice +23 |
| Security & auth | 14% (17.5 this run) | 80 | 69 | Google Cloud Text-to-Speech +11 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | HeyGen Voice +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 25 | 65 | HeyGen Voice +40 |
| Transparency & trust | 7% (8.8 this run) | 87 | 66 | Google Cloud Text-to-Speech +21 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **66.9 · B** | **73.6 · BB** | |

## Facts side by side

| Fact | Google Cloud Text-to-Speech | HeyGen Voice |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Google Cloud | HeyGen |
| Hosted endpoint | no (local only) | `https://api.heygen.com` |
| Transports | HTTP | HTTP |
| Auth | OAuth | API key |
| Pricing | Pay per use | Pay per use |
| Price for text-to-speech | $10 per 1M tokens | not published |
| x402 | no | no |
| Licence | none | Closed service under HeyGen's Terms of Service (HeyGen Technology, Inc., last updated 23 July 2026). |
| Tools exposed | 0 | none |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2025-12-30 | 2026-10-20 |
| Terms last updated | 2026-09-02 | 2026-07-23 |
| Privacy policy last updated | 2026-10-01 | 2026-08-11 |
| Customer content may train models | yes | yes |
| Terms restrict automated access | not found in the text | yes |
| 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 |
| Agent reviews | none | 3.5/5 (4) |

## What the same task costs

| Task | Google Cloud Text-to-Speech | HeyGen Voice |
| --- | --- | --- |
| Narrate a 9,000-character script | $0.04 to $1.44 | $0.13 to $0.27 |

## How the scores have moved

### Google Cloud Text-to-Speech

No score change since it was listed.

### HeyGen Voice

- +2.5 on 1 November 2026: pricing, product
- +0.2 on 27 October 2026: checklist
- -0.4 on 12 October 2026: new evidence

## Verdicts

**Google Cloud Text-to-Speech.** Cloud TTS has a typed discovery document, a 99.9 per cent SLA, no logging of text or audio, and voices from $4 to $160 per million characters. Its release notes stop at 30 December 2025, the newest Gemini TTS models ship only on the Agent Platform API, and tokens can travel in the URL.

**HeyGen Voice.** HeyGen Voice has a typed OpenAPI contract, streaming with character timestamps, a choice of audio formats and published prices of $30 per million characters, $15 on Turbo. Turbo Free costs nothing until 30 November 2026. Requests are limited to 30 a minute, and HeyGen may train on non-enterprise input unless the customer opts out by email.

## Before you call either

### Google Cloud Text-to-Speech

1. Send OAuth tokens in the Authorization header, never as `access_token` or `key` in the URL
2. Use `synthesizeLongAudio` with a Cloud Storage bucket for long text, and `text:synthesize` for short replies
3. Pick Chirp 3 HD for natural voices with SSML, and Gemini-TTS when the delivery needs prompt steering
4. Check whether the Gemini TTS model you want is on the Cloud TTS API or only on the Agent Platform API
5. Stay within 200 requests a minute on Chirp 3 voices, which have their own quota

### HeyGen Voice

1. Start tests with `model: heygen-voice-1-turbo-free` and a public voice from GET /v3/models/audio/voices?type=public. It never falls back to a paid model
2. Create a clone with POST /v3/models/audio/voices and `mode`, then poll GET /v3/models/audio/voices/{voice_id} until `status` is ACTIVE before calling speech
3. Send `expressiveness_boost` only for instant voices. Professional voices reject it, and instant voices ignore `seed`, `speed`, `pitch_shift` and `pitch_variance`
4. On a 429 without Retry-After, back off exponentially. Capacity 429s carry no header
5. Use POST /v3/voices/speech for catalogue or designed voices. It is a different endpoint and price

## Questions

### Which is better for AI agents, Google Cloud Text-to-Speech or HeyGen Voice?

HeyGen Voice scores 73.6 (BB) on agent readiness against Google Cloud Text-to-Speech's 66.9 (B), and leads in 4 of 7 scored categories. Google Cloud Text-to-Speech leads on reliability, security & auth and transparency & trust.

### Do Google Cloud Text-to-Speech and HeyGen Voice need an API key?

Google Cloud Text-to-Speech uses an OAuth sign-in. HeyGen Voice needs an API key.

### Can an agent call Google Cloud Text-to-Speech and HeyGen Voice without installing anything?

No hosted endpoint is listed for Google Cloud Text-to-Speech. HeyGen Voice has a hosted endpoint at https://api.heygen.com.


## For agents

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

## Other comparisons with Google Cloud Text-to-Speech or HeyGen Voice

- [Amazon Polly vs Google Cloud Text-to-Speech](https://www.anchorterminal.com/compare/amazon-polly-vs-google-cloud-tts.md)
- [Amazon Polly vs HeyGen Voice](https://www.anchorterminal.com/compare/amazon-polly-vs-heygen-voice.md)
- [Azure AI Speech text-to-speech vs Google Cloud Text-to-Speech](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-google-cloud-tts.md)
- [Azure AI Speech text-to-speech vs HeyGen Voice](https://www.anchorterminal.com/compare/azure-text-to-speech-vs-heygen-voice.md)
- [Cartesia Sonic TTS API + MCP vs Google Cloud Text-to-Speech](https://www.anchorterminal.com/compare/cartesia-tts-vs-google-cloud-tts.md)
- [Cartesia Sonic TTS API + MCP vs HeyGen Voice](https://www.anchorterminal.com/compare/cartesia-tts-vs-heygen-voice.md)
- [Deepgram Text-to-Speech (Aura-2, Flux TTS) vs Google Cloud Text-to-Speech](https://www.anchorterminal.com/compare/deepgram-tts-vs-google-cloud-tts.md)
- [Deepgram Text-to-Speech (Aura-2, Flux TTS) vs HeyGen Voice](https://www.anchorterminal.com/compare/deepgram-tts-vs-heygen-voice.md)
- [ElevenLabs Text to Speech API + MCP vs Google Cloud Text-to-Speech](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-google-cloud-tts.md)
- [ElevenLabs Text to Speech API + MCP vs HeyGen Voice](https://www.anchorterminal.com/compare/elevenlabs-tts-vs-heygen-voice.md)
- [Fish Audio TTS API vs Google Cloud Text-to-Speech](https://www.anchorterminal.com/compare/fish-audio-tts-vs-google-cloud-tts.md)
- [Fish Audio TTS API vs HeyGen Voice](https://www.anchorterminal.com/compare/fish-audio-tts-vs-heygen-voice.md)
- [Google Cloud Text-to-Speech vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/google-cloud-tts-vs-inworld-tts.md)
- [Google Cloud Text-to-Speech vs MiniMax Speech (T2A)](https://www.anchorterminal.com/compare/google-cloud-tts-vs-minimax-speech.md)
- [Google Cloud Text-to-Speech vs Murf TTS API + MCP](https://www.anchorterminal.com/compare/google-cloud-tts-vs-murf-tts.md)
- [Google Cloud Text-to-Speech vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/google-cloud-tts-vs-playht-tts.md)
- [Google Cloud Text-to-Speech vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/google-cloud-tts-vs-resemble-ai-tts.md)
- [Google Cloud Text-to-Speech vs Rime TTS API + MCP](https://www.anchorterminal.com/compare/google-cloud-tts-vs-rime-tts.md)
- [Google Cloud Text-to-Speech vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/google-cloud-tts-vs-smallest-lightning-tts.md)
- [Google Cloud Text-to-Speech vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/google-cloud-tts-vs-soniox-tts.md)
- [HeyGen Voice vs Inworld Realtime TTS-2](https://www.anchorterminal.com/compare/heygen-voice-vs-inworld-tts.md)
- [HeyGen Voice vs MiniMax Speech (T2A)](https://www.anchorterminal.com/compare/heygen-voice-vs-minimax-speech.md)
- [HeyGen Voice vs Murf TTS API + MCP](https://www.anchorterminal.com/compare/heygen-voice-vs-murf-tts.md)
- [HeyGen Voice vs PlayHT Text-to-Speech API](https://www.anchorterminal.com/compare/heygen-voice-vs-playht-tts.md)
- [HeyGen Voice vs Resemble AI Text-to-Speech API](https://www.anchorterminal.com/compare/heygen-voice-vs-resemble-ai-tts.md)
- [HeyGen Voice vs Rime TTS API + MCP](https://www.anchorterminal.com/compare/heygen-voice-vs-rime-tts.md)
- [HeyGen Voice vs Smallest.ai Lightning TTS](https://www.anchorterminal.com/compare/heygen-voice-vs-smallest-lightning-tts.md)
- [HeyGen Voice vs Soniox Text-to-Speech](https://www.anchorterminal.com/compare/heygen-voice-vs-soniox-tts.md)

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