kitio.aiCartesia Sonic vs Inworld AI
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Cartesia Sonic has the lower starting price: about $5 a month, against $25 for Inworld AI.
Realtime text-to-speech, speech-to-text and LLM inference for consumer apps
Freemium · $25/moAt 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
- Realtime TTS-2 and TTS-2 Flash
- Speech-to-text
- Speech-to-speech
- Voice cloning and design
- Open LLM inference
- Credit rollover
| Feature | Cartesia Sonic | Inworld AI |
|---|---|---|
| Best for | Low-latency text-to-speech API for voice agents | Realtime text-to-speech, speech-to-text and LLM inference for consumer apps |
| Category | Audio & voice | Audio & voice |
| Pricing model | Freemium | Freemium |
| Starting price | $5/mo | $25/mo |
| Free plan | Yes | Yes |
| Made by | Cartesia | Inworld AI |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
Cartesia Sonic has the lower starting price: about $5 a month, against $25 for Inworld AI.
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
6 plans
On-Demand
$25 / 1M characters (TTS-2)
- Pay as you go
- Up to 70 min TTS included
- 2 professional voice clones
Creator
$25/mo
- $25 in credits per month
- Up to 33% off TTS and STT
- 4 professional voice clones
Builder
$100/mo
- $100 in credits per month
- Up to 40% off TTS and STT
- 10 professional voice clones
Developer
$300/mo
- $300 in credits per month
- Up to 47% off TTS and STT
- Priority email support
Growth
$1500/mo
- $1,500 in credits per month
- Up to 53% off TTS and STT
- Higher API limits
Enterprise
Custom
- TTS-2 from $5 per 1M characters
- SLA and data residency
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
Inworld AI
- Very low latency for live voice
- Pay-as-you-go option
- Unused credits roll over
- Best rates need large commitments
- HIPAA and ZDR are add-ons
- Developer-oriented, no consumer app
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 Inworld AI if you want:
- Very low latency for live voice
- Pay-as-you-go option
- Unused credits roll over
Watch out: best rates need large commitments.
Cartesia Sonic vs Inworld AI FAQ
What is the difference between Cartesia Sonic and Inworld AI?
Cartesia Sonic: Low-latency text-to-speech API for voice agents. Inworld AI: Realtime text-to-speech, speech-to-text and LLM inference for consumer apps. Both are audio & voice tools.
Is Cartesia Sonic or Inworld AI cheaper?
Cartesia Sonic has the lower starting price: about $5 a month, against $25 for Inworld AI.
Do Cartesia Sonic and Inworld AI have free plans?
Cartesia Sonic: Yes. Inworld AI: Yes.
Who makes Cartesia Sonic?
Cartesia Sonic is made by Cartesia, based in United States.
Who makes Inworld AI?
Inworld AI is made by Inworld AI, based in United States.
Which should I choose, Cartesia Sonic or Inworld AI?
Choose Cartesia Sonic if you value very fast time to first audio and wide language coverage in one model. Choose Inworld AI if you value very low latency for live voice and pay-as-you-go option.