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AI · head to head

Cartesia vs Koyeb

Cartesia logo

Cartesia

AI

Real-time voice AI platform for speech generation, transcription, and voice agents

From
Free
Free plan
Yes
Full reviewWebsite
Koyeb logo

Koyeb

Cloud

High-performance serverless infrastructure for APIs, inference, and databases

From
$29/month
Free plan
No
Full reviewWebsite

The short version

  • Only Cartesia has a free tier, so it costs nothing to try first.
  • Each has a real cost: Cartesia instant and professional voice cloning are gated behind paid Pro and Startup tiers, unavailable on the free plan.; Koyeb pricing starts at $29/month with additional compute costs
  • They diverge on capability: Cartesia covers Sonic text-to-speech, Koyeb covers Serverless containers.
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Cartesia and Koyeb actually diverge.

Attributes where Cartesia and Koyeb differ
AttributeCartesiaKoyeb
Starting priceFree$29/month
Pricing modelfreemiumUnknown
Free tierYesNo
Platformsweb, apiWeb, CLI, API
CategoryAICloud

Identical on both: user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Cartesia

  • Sonic text-to-speech
  • Ink speech-to-text
  • Line voice agent platform
  • Instant and professional voice cloning
  • Flexible deployment
  • Telephony integration

Only in Koyeb

  • Serverless containers
  • GPU support
  • Global distribution
  • Multi-protocol support
  • Serverless Postgres
  • Zero-downtime deployments

What people use each for

The jobs each tool is most often brought in to do.

Cartesia

  • Building low-latency voice agents for customer supportnot Koyeb
  • Real-time transcription for conversational applicationsnot Koyeb
  • Voice cloning for branded synthetic voicesnot Koyeb
  • On-device or on-premise voice AI for regulated industriesnot Koyeb

Koyeb

  • Deploying AI inference models globally with GPU accelerationnot Cartesia
  • Building SaaS platforms with automatic scalingnot Cartesia
  • Running distributed AI agents and background workersnot Cartesia

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Cartesia

  • Instant and professional voice cloning are gated behind paid Pro and Startup tiers, unavailable on the free plan.
  • Voice agent calls carry a separate per-minute usage fee ($0.06/minute) on top of subscription credits.
  • Enterprise features like SSO and BAAs require a custom sales conversation rather than self-serve upgrade.
  • Free tier concurrency limits (2 TTS, 8 STT concurrent requests) may be restrictive for testing production-like load.

Koyeb

  • Pricing starts at $29/month with additional compute costs
  • GPU compute is expensive at $0.75-$2.50 per hour
  • Limited customization for infrastructure configuration

Pricing, plan by plan

Cartesia

Free
  • FreeFree
    • 20,000 credits/month
    • TTS and STT included
    • 2 concurrent TTS requests, 8 concurrent STT requests
  • Pro$4/month
    • 100,000 credits/month
    • Commercial use license
    • Instant voice cloning
  • Startup$39/month
    • 1.25M credits/month
    • Professional voice cloning
    • Organizations support
  • Scale$239/month
    • 8M credits/month
    • Priority support
    • High concurrency limits

Koyeb

$29/month
  • Pro$29/month
    • $10 included compute
    • 10 users
    • 100 services
  • Scale$299/month
    • $100 included compute
    • 50 users
    • 1,000 services
  • Enterprise$1000/month
    • Unlimited users
    • Custom resources
    • SSO/RBAC

Which should you pick?

Choose Cartesia if

  • You need sonic text-to-speech.
  • You want to start without paying.
  • You work on web, api.
  • You also want ink speech-to-text.
Cartesia review

Choose Koyeb if

  • You need serverless containers.
  • You work on Web, CLI, API.
  • You also want gpu support.
Koyeb review

Questions people ask

Is Cartesia or Koyeb better?
Neither clearly leads. Cartesia starts at Free and Koyeb at $29/month, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cartesia or Koyeb?
Cartesia has a free tier; the other does not. Paid plans start at Free for Cartesia and $29/month for Koyeb.
Does Cartesia or Koyeb run on more platforms?
Cartesia runs on web, api. Koyeb runs on Web, CLI, API.
Can I use Cartesia for free?
Yes. Cartesia has a free tier, so you can try it without paying. Koyeb starts at $29/month.
What is Cartesia best used for?
Cartesia is most often used for building low-latency voice agents for customer support, real-time transcription for conversational applications, voice cloning for branded synthetic voices, on-device or on-premise voice ai for regulated industries. Of those, building low-latency voice agents for customer support and real-time transcription for conversational applications are not what Koyeb is typically brought in for.
What can Cartesia do that Koyeb cannot?
Cartesia covers Sonic text-to-speech, Ink speech-to-text, Line voice agent platform, Instant and professional voice cloning. Koyeb covers Serverless containers, GPU support, Global distribution, Multi-protocol support.

Answered from the vendors’ own pages

Cartesia: What does Cartesia cost?

Cartesia offers a free plan, Pro at $4/month, Startup at $39/month, Scale at $239/month, and custom Enterprise pricing, each including a monthly credit allotment, with annual billing saving 20%.

Source
Koyeb: What are Koyeb's subscription plans?

Pro plan is $29/month with $10 included compute, Scale plan is $299/month with $100 included compute and 99.9% SLA, and Enterprise starts at $1,000/month with unlimited users and 99.99% SLA.

Source
Cartesia: Is there a free plan, and what are its limits?

The Free plan includes 20,000 credits per month, both TTS (Sonic) and STT (Ink), 2 concurrent TTS requests, 8 concurrent STT requests, and 1 voice agent slot.

Source
Koyeb: How much does GPU compute cost?

GPU pricing is per-second: RTX-A6000 costs $0.75/hour, A100 costs $1.60/hour, H100 costs $2.50/hour, and 8x H100 costs $20.00/hour.

Source
Cartesia: How is usage metered?

Usage draws down a monthly credit allotment, with voice agent calls additionally billed at $0.06/minute and telephony via Cartesia phone numbers at $0.014/minute.

Source
Koyeb: What database options are available?

Koyeb offers serverless Postgres starting at free (0.25 vCPU, 1GB RAM) up to 3XL at $1.28/hour with 8 vCPU and 32GB RAM. Storage costs $0.50/month per GB.

Source
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