kitio.aiCartesia Sonic vs IBM Text to Speech
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Cartesia Sonic starts at $5/mo and IBM Text to Speech starts at See pricing page. Check both pricing pages for current plans.
At a glance
Best for
Category
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Real-time speech under 90ms
- 44 languages
- Instant voice cloning
- Emotion and laughter control
- Voice localisation
- Neural voices
- SSML controls
- Voice transformation
- Custom branded voices
- Custom pronunciations
| Feature | Cartesia Sonic | IBM Text to Speech |
|---|---|---|
| Best for | Low-latency text-to-speech API for voice agents | Neural voice API with SSML controls and custom branded voices |
| Category | Audio & voice | Audio & voice |
| Pricing model | Freemium | Freemium |
| Starting price | $5/mo | See pricing page |
| Free plan | Yes | Yes |
| Made by | Cartesia | IBM |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
Cartesia Sonic starts at $5/mo and IBM Text to Speech starts at See pricing page. Check both pricing pages for current plans.
Free plan
Cheapest paid plan
Top plan
Free trial
5 plans
Free
Free
- 20K credits per month
- Text to speech and speech to text
- $1 of prepaid voice agent usage
Pro
$5/mo
- 100K credits per month
- Commercial use license
- Instant voice cloning
Startup
$49/mo
- 1.25M credits per month
- Professional voice cloning
- $49 of prepaid agent usage
Scale
$299/mo
- 8M credits per month
- Priority support
- High concurrency limits
Enterprise
Contact sales
- Custom credits and volume pricing
- SSO and DPAs
- Shared Slack channel
Prices in USD, checked Oct 29, 2026 or later. Plans change often, so confirm on each tool's site before you buy.
Pros and cons
Cartesia Sonic
- Very fast time to first audio
- Wide language coverage in one model
- Cloning from ten seconds of audio
- Aimed at developers more than casual users
- Credit system takes a while to understand
- Commercial license needs a paid plan
IBM Text to Speech
- Fine control through SSML
- Custom voice from one hour of audio
- Fits with IBM speech and assistant tools
- Custom voices are a premium extra
- Fewer voices than newer TTS startups
- Pricing not shown on the product page
Which one should you choose?
Choose Cartesia Sonic if you want:
- Very fast time to first audio
- Wide language coverage in one model
- Cloning from ten seconds of audio
Watch out: aimed at developers more than casual users.
Choose IBM Text to Speech if you want:
- Fine control through SSML
- Custom voice from one hour of audio
- Fits with IBM speech and assistant tools
Watch out: custom voices are a premium extra.
Cartesia Sonic vs IBM Text to Speech FAQ
What is the difference between Cartesia Sonic and IBM Text to Speech?
Cartesia Sonic: Low-latency text-to-speech API for voice agents. IBM Text to Speech: Neural voice API with SSML controls and custom branded voices. Both are audio & voice tools.
Is Cartesia Sonic or IBM Text to Speech cheaper?
Cartesia Sonic starts at $5/mo and IBM Text to Speech starts at See pricing page. Check both pricing pages for current plans.
Do Cartesia Sonic and IBM Text to Speech have free plans?
Cartesia Sonic: Yes. IBM Text to Speech: Yes.
Who makes Cartesia Sonic?
Cartesia Sonic is made by Cartesia, based in United States.
Who makes IBM Text to Speech?
IBM Text to Speech is made by IBM, based in United States.
Which should I choose, Cartesia Sonic or IBM Text to Speech?
Choose Cartesia Sonic if you value very fast time to first audio and wide language coverage in one model. Choose IBM Text to Speech if you value fine control through ssml and custom voice from one hour of audio.