Articulate · Talk Better · Voice

AI voice agents, compared.

The twelve platforms that turn an LLM into a phone call — what they are, what they cost, where they break, who they're for. Tap any one for the full page.

A reference from Articulate · compiled June 2026
01 · The shape of the market

Four layers. Read this first.

A voice agent is assembled from four layers. Most "which platform is best?" arguments are really arguments between layers — knowing which one your problem lives in narrows twelve options to two or three.

1 · Models — the raw capability

STT · LLM brain · TTS

Deepgram / ElevenLabs Scribe (hear) · OpenAI / Claude / Gemini (think) · ElevenLabs / Cartesia (speak) — or a native speech-to-speech model (OpenAI GPT-Realtime, Gemini Live). Note: Claude has no native speech-to-speech, so a "Claude voice agent" is always the stitched STT→Claude→TTS path.

2 · Orchestration — build-your-own

Vapi · Retell · Bland · Synthflow · Voiceflow

You design the flow, pick models, connect telephony. Days-to-weeks to ship, transparent per-minute pricing. The DIY / agency layer — and where an Articulate-built agent lives.

3 · Infrastructure — the transport

LiveKit · ElevenLabs

The WebRTC/SIP plumbing and voice engine the platforms themselves run on. Use directly only if you're building your own platform or need full data-sovereign control.

4 · Managed agents — bought, not built

Sierra · Decagon · PolyAI · SquadStack · Leaping

Done-for-you, vertical, contract-priced ($150K–$1M+/yr). You buy an outcome, not a builder.

02 · The twelve

Every platform, one tap away.

Tap a card for the full page — what it is, key features, where it breaks, real use cases, pricing, and Articulate's take. build · models/infra · managed

03 · Side by side

The comparison.

Pricing transparency: clear mixed opaque. Rows are tappable.

PlatformBest forLatencyPricingShipEdge

Vendor-stated or third-party-reported, June 2026. Verify against a live pilot before committing.

04 · Pick for the job

Who you are → what to use.

The honest match. Tap a tool chip to open its full page.

05 · The short path

How to choose.

Building it yourself / want Claude as the brain? → Vapi (max control) or Retell (best balance). The home for any Articulate-built agent.
An agency running many client lines, no-code? → Synthflow (multi-tenant).
Designing the conversation before you build? → Voiceflow to prototype, then ship on Retell/Vapi.
Data-sovereign, self-hosted, regulated client? → LiveKit + Claude + local STT/TTS.
Best voice quality / branded voice identity? → ElevenLabs as the voice layer inside any of the above.
Buying a done-for-you enterprise outcome? → Sierra (brand-grade), PolyAI (multilingual), Decagon (DTC volume).
06 · Articulate's position

What this settles.