Top 9 of 17 alternatives

Synthflow alternatives like ElevenLabs Agents and Retell AI

The closest alternatives to Synthflow in October 2026 are ElevenLabs Agents, Retell AI and Bland.

Updated 28 October 2026

9 agents compared · 4 with a free plan · prices checked 2 September–29 October 2026

Reviewed by The Agents Index editorial team.

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Synthflow and its alternatives at a glance

Agent	Best for	Starts at	Better than Synthflow at	Checked
Synthflow	Operations and CX teams at mid-market or enterprise companies who want a visual, no-code way to design and launch phone agents without an engineering ticket.	From $30,000 a year source		3 September 2026
ElevenLabs Agents	Developers and product teams who want ElevenLabs' voice quality and cloning as the foundation of their agent, and are comfortable assembling the rest of the stack themselves.	Free, then $6 a month source	Claude, Open models	18 October 2026
Retell AI	Product and engineering teams that want a low-latency, human-sounding phone agent with flexible model and telephony choice.	From $0.07 per minute source	Claude, Open models	23 September 2026
Bland	Security-conscious enterprises in regulated industries that want a compliant, infrastructure-owned voice platform with deterministic call flows.	Free, then $0.14 per minute source	In your editor, On the command line	18 October 2026
LiveKit Agents	Engineering teams that want to own their voice-agent stack end to end, self-hosted or on LiveKit Cloud, without being locked into one vendor's API.	Free, then $50 a month source	Claude, Open models	2 September 2026
Vapi	Engineering teams that want maximum control to build custom voice agents on their own choice of model, voice and telephony.	From $0.05 per minute source	Claude, Open models	3 September 2026
OpenAI Realtime API	Engineering teams building a voice agent from scratch who want to go directly to OpenAI's own speech-to-speech model (no orchestration platform, no per-minute markup) and are comfortable being single-vendor on OpenAI.	From $10 per 1m input tokens source	On the command line, Open source	25 October 2026
Cartesia	Engineering teams that want an open-source voice-agent SDK with real LLM choice, built on speech models several rival platforms in this category already license as a component.	Free, then $5 a month source	Claude, Open models	2 September 2026
Deepgram Voice Agent API	Engineering teams that want a managed speech pipeline with real LLM-provider choice, and regulated enterprises that need a self-hosted or VPC deployment option a typical closed-source voice-agent vendor does not offer.	From $0.05 per minute source	Claude, Open models	2 September 2026

Closest alternatives to Synthflow

The ones people open most here come first, then the closest matches. How we check

Where Synthflow falls short: Real per-minute cost on PAYG is the sum of separately-billed components (voice engine + LLM + telephony + optional add-ons), and PAYG is no longer advertised on the public pricing page. The Enterprise floor is $30,000/year.

1
ElevenLabs Agents
From Free
Hosted platform for building voice and chat agents, with telephony, SDKs and a choice of LLM.
Why it's on this list
Claude: YesAnthropic models are natively selectable in agent settings; a few older Claude models drop out in EU data-residency workspaces.
Source ↗
Better than Synthflow at
- Open models: Yes ↗
- Model choice: Yes ↗
Trade-offs
- In your editor: No ↗
- Admin controls: Partly ↗
Watch for
Covers the voice + LLM-orchestration layer, not a turnkey ops product, CRM/helpdesk workflows, observability and compliance UI are yours to build.
2
Retell AI
From $0.07 per minute
Pay-as-you-go platform for building, testing and running AI phone, chat and SMS agents.
Why it's on this list
Claude: YesAnthropic models are first-class choices on the pay-as-you-go plan, each with its own published per-minute voice rate and per-message chat rate, from Claude Haiku tiers up to Opus; one Sonnet tier is even flagged as a recommended default.
Source ↗
Better than Synthflow at
- Open models: Partly ↗
- Model choice: Yes ↗
Trade-offs
- Agent permissions: Partly ↗
- Free tier: Partly ↗
Watch for
True per-minute cost is the sum of stacked components, so budgeting requires modelling model, voice, and telephony together.
3
Bland
From Free
Enterprise voice AI platform for inbound and outbound phone agents, running on Bland's own self-hosted models.
Why it's on this list
In your editor: YesAn MCP server puts agent building inside Claude Code, Cursor, VS Code and Codex; the agent itself still runs on calls.
Source ↗
Better than Synthflow at
- On the command line: Yes ↗
- Self-hosted: Partly ↗
Trade-offs
- Multi-agent: Partly ↗
- Agent permissions: Partly ↗
Watch for
Voice cloning across the full 40+ language set and the lowest per-minute rates are effectively Enterprise-tier features.

The rest of the shortlist

LiveKit Agents
Open-source Python and Node.js framework for voice AI agents, with LiveKit Cloud hosting, telephony and observability.
Watch for: A framework, not a no-code or dashboard-first builder. Expect to write and deploy real code, unlike this category's more configured rivals.
From Free
Vapi
Developer platform for building, testing and deploying voice AI agents that make and receive phone calls.
Watch for: True per-minute cost is the sum of several passed-through services, so the headline platform fee understates spend.
From $0.05 per minute
OpenAI Realtime API
Speech-to-speech voice agent API with tools, interruptions and WebRTC, WebSocket or SIP transports.
Watch for: 60-minute maximum session duration.
From $10 per 1m input tokens
Cartesia
Real-time speech models and a managed runtime for production phone and web voice agents.
Watch for: Line's voice-agent runtime cannot be self-hosted — only the underlying Sonic/Ink models can, on an Enterprise contract.
From Free
Deepgram Voice Agent API
One WebSocket API that runs speech-to-text, LLM orchestration and text-to-speech for real-time voice agents.
Watch for: No dedicated free tier. A one-time $200 credit only, then usage billing from the first paid session.
From $0.05 per minute
Telnyx Voice AI AgentsVerified owner
Carrier-owned platform for phone and web voice agents, with telephony, STT, TTS, LLM and orchestration in one stack.
From $0.05 per minute