Last updated: 2026-06 · 5 min read
Cartesia vs PlayAI (2026): Low-Latency Voice Layer vs a Shut-Down Provider
Our verdict: Cartesia
Cartesia is the clear pick because PlayAI is no longer available — Meta acquired the team in July 2025, the public API went dark on July 26, 2025, and the platform shut down permanently on December 31, 2025, deleting accounts and voice clones. Cartesia is a developer-grade voice layer whose Sonic TTS model targets ultra-low latency (time-to-first-audio reported under ~100ms), making it a strong fit for custom AI receptionist stacks built on LiveKit, Pipecat, Vapi, or Retell. PlayAI is included only as a reference and a cautionary tale about single-vendor acquisition risk; former users typically migrate to Cartesia, ElevenLabs, or Murf. Both are voice layers, not turnkey receptionists — you still wire in your own LLM, STT, and telephony.
| Cartesia | PlayAI (Play.ht) | |
|---|---|---|
| Best for | Agencies and developers who want the fastest, most natural voice layer inside a custom-built AI receptionist stack (e.g. paired with LiveKit, Pipecat, Vapi, or Retell) | Reference only — understanding the voice-AI landscape and recent consolidation |
| Latency | Very low (~90ms model / ~190ms end-to-end; time-to-first-audio under ~100ms reported) | Historically low (~180ms TTS, vendor-cited sub-100ms first token) — but moot now that the service is offline |
| Starting price | $0/mo | $0 |
| White-label | No | No |
| Setup time | Developer integration required (hours to days, depending on stack); not a no-code setup | N/A — service discontinued; no new sign-ups since August 2025 |
| LLM support | N/A — voice/TTS + STT layer (bring your own LLM via LiveKit, Pipecat, Vapi, Retell, or Cartesia's Line platform) | N/A — voice/TTS layer (bring-your-own LLM for agent logic; service now discontinued) |
| Rating | 3.9/5 | 1.5/5 |
Cartesia
★★★Cartesia is a voice-AI infrastructure company whose flagship Sonic text-to-speech model is built on state space models for ultra-low latency, with time-to-first-audio reported under ~100ms. It also offers the Ink speech-to-text model and, more recently, a "Line" voice-agent development platform, but at its core it is a developer-grade voice layer rather than a turnkey receptionist product. For agencies, it is the engine you plug into a voice stack (LiveKit, Pipecat, Vapi, Retell), not a finished product you hand to a local business.
Pros
- ✓Genuinely class-leading latency: Sonic reports time-to-first-audio under ~100ms, which keeps voice conversations feeling natural and reduces the awkward pauses that kill receptionist calls
- ✓Low, predictable per-minute economics (~$0.03/min for TTS at pay-as-you-go) and a usable free tier make it cheap to prototype and test
- ✓Owns its full voice stack (Sonic TTS, Ink STT, and the Line agent platform), so latency and reliability are optimized end-to-end rather than stitched across vendors
Cons
- ✗No white-label, reseller, or agency program found in public materials, so you cannot resell it to clients under your own brand the way a turnkey receptionist platform allows
- ✗It is a developer/infrastructure layer, not a finished receptionist product: there is no out-of-the-box dashboard, calendar booking, or business workflow your local-business client could use without you building around it
Independent review. NeuroByte may earn a referral commission if you sign up through this link.
PlayAI (Play.ht)
★PlayAI (formerly Play.ht) was a well-regarded text-to-speech, voice-cloning, and voice-agent platform that offered 800+ realistic AI voices and a low-latency TTS API used to build conversational phone agents. In July 2025 Meta acquired the roughly 35-person team into its Superintelligence Labs division; the public API went dark on July 26, 2025, new sign-ups stopped in August 2025, and the platform was permanently shut down on December 31, 2025, with accounts and voice clones deleted. For agencies building AI receptionists today it is effectively unavailable — included here as a reference and a cautionary tale about building on a single acquisition-risk vendor.
Pros
- ✓Genuinely strong TTS quality in its day — 800+ voices across many languages with natural inflection
- ✓Low-latency TTS API (vendor cited sub-200ms, ~180ms) capable of powering real-time conversational voice agents
- ✓Offered voice cloning and an on-premise deployment option that appealed to privacy-sensitive enterprises
Cons
- ✗Discontinued: API went offline July 2025 and the full platform shut down December 31, 2025 — you cannot build on it today
- ✗Acquisition wind-down was abrupt — accounts, saved audio, and voice clones were deleted with no migration path
Reference only - PlayAI / Play.ht was acquired by Meta and permanently shut down on December 31, 2025. It is no longer available to new users; see the alternatives in the comparison links below.
Pricing Comparison
Cartesia
PlayAI (Play.ht)
When to Choose Each
Choose Cartesia if…
- →Agencies and developers who want the fastest, most natural voice layer inside a custom-built AI receptionist stack (e.g. paired with LiveKit, Pipecat, Vapi, or Retell)
- →Teams that prioritize sub-second response latency and are comfortable wiring an LLM, STT, and telephony together themselves
- →Builders who want low per-minute voice costs and the option to use Cartesia's own Line platform to deploy agents at scale
Choose PlayAI (Play.ht) if…
- →Reference only — understanding the voice-AI landscape and recent consolidation
- →A cautionary example of vendor/acquisition risk when choosing a voice layer for client work
- →Former users who need to migrate (ElevenLabs, Cartesia, or Murf are common replacements)