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Arize AI vs Cartesia

Arize AI logo

Arize AI

Software

AI engineering platform for observability and evaluation of agents and LLM apps

From
Free
Rated
-
Full reviewWebsite
Cartesia logo

Cartesia

Software

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

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Arize AI the free plan caps trace spans at 25,000 per month with only 15 days of retention.; Cartesia instant and professional voice cloning are gated behind paid Pro and Startup tiers, unavailable on the free plan.
  • They diverge on capability: Arize AI covers End-to-end tracing, Cartesia covers Sonic text-to-speech.

Where they differ

Only the attributes on which Arize AI and Cartesia actually diverge.

Attributes where Arize AI and Cartesia differ
AttributeArize AICartesia

Identical on both: starting price (Free), pricing model (freemium), free tier (Yes), platforms (web, api), user rating (Not yet rated), category (Unknown).

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 Arize AI

  • End-to-end tracing
  • Evaluation framework
  • Prompt testing and improvement
  • Alyx AI engineering agent
  • Custom dashboards
  • Data warehouse integrations

Only in Cartesia

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

What people use each for

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

Arize AI

  • Tracing and debugging production AI agentsnot Cartesia
  • Running large-scale evaluations across traces and sessionsnot Cartesia
  • Improving prompts before production rolloutnot Cartesia
  • Storing and querying GenAI traces alongside a data warehousenot Cartesia

Cartesia

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

Where each one falls short

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

Arize AI

  • The free plan caps trace spans at 25,000 per month with only 15 days of retention.
  • Self-hosted deployment and Data Fabric integration are restricted to the custom-priced Enterprise tier.
  • Pricing beyond the $50/month Pro plan requires a custom quote, making cost planning less transparent at scale.
  • Advanced compliance features like HIPAA are only available on Enterprise.

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.

Pricing, plan by plan

Arize AI

Free
  • AX FreeFree
    • 25k trace spans/month
    • 1 GB storage/month
    • 15-day retention
  • AX Pro$50/month
    • 50k trace spans/month
    • 10 GB storage/month
    • 30-day retention
  • AX Enterprise$undefined/mo
    • Custom trace spans, storage, and retention
    • SaaS or self-hosted deployment
    • Managed agents and Data Fabric

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

Which should you pick?

Choose Arize AI if

  • You need end-to-end tracing.
  • You want to start without paying.
  • You work on web, api.
  • You also want evaluation framework.
Arize AI review

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

Questions people ask

Is Arize AI or Cartesia better?
Neither clearly leads. Arize AI starts at Free and Cartesia at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Arize AI or Cartesia?
Arize AI starts at Free and Cartesia at Free.
Does Arize AI or Cartesia run on more platforms?
Both run on web, api, so platform support will not decide this one for you.
Can I use Arize AI for free?
Both have a free tier, so you can try either at no cost before committing.
What is Arize AI best used for?
Arize AI is most often used for tracing and debugging production ai agents, running large-scale evaluations across traces and sessions, improving prompts before production rollout, storing and querying genai traces alongside a data warehouse. Of those, tracing and debugging production ai agents and running large-scale evaluations across traces and sessions are not what Cartesia is typically brought in for.
What can Arize AI do that Cartesia cannot?
Arize AI covers End-to-end tracing, Evaluation framework, Prompt testing and improvement, Alyx AI engineering agent. Cartesia covers Sonic text-to-speech, Ink speech-to-text, Line voice agent platform, Instant and professional voice cloning.

Answered from the vendors’ own pages

Arize AI: What does Arize AX cost?

Arize AX offers a free plan, a Pro plan at $50/month, and a custom-priced Enterprise plan, with pricing based on trace spans, storage, and retention needs.

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

The AX Free plan includes 25,000 trace spans and 1 GB of storage per month with 15-day retention, plus unlimited users, evaluations, and experiments.

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
Arize AI: What deployment options are available?

Free and Pro plans are SaaS-only, while Enterprise customers can choose SaaS or self-hosted deployment with custom SLAs.

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
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