7 best Retell AI alternatives for voice AI agents in 2026

The strongest Retell AI alternatives in October 2026 are Vapi for developers replacing Retell like for like, with per-minute pricing and their own transcriber, model and voice; ElevenAgents (ElevenLabs) if voice quality and price per minute matter most; and Robylon for support teams that want phone calls answered by the same AI voice agent that handles chat, email and WhatsApp, with a human inbox behind it. Bland AI and Synthflow suit teams that want a bundled rate or a no-code builder, and PolyAI and Cognigy suit enterprise contact centers.

Retell AI is a capable platform for building AI phone agents: it publishes every per-minute component, charges no platform fee, and lets developers choose the LLM, the voice and the telephony. Teams evaluating or running Retell look elsewhere when they want more provider control, a no-code builder or a finished product, or when the phone line has to sit beside chat, email and WhatsApp for one support team. Every tool below is judged on three things: whether the agent takes the action a call needs, whether every channel runs from one setup, and whether it fits the stack you already run.

Retell AI alternatives at a glance

Prices checked October 2026 on each vendor's pricing page. G2 ratings read October 2026, with the review count in brackets.

Robylon publishes this page and ranks itself first; every tool on the list, Robylon included, gets the same “Where it falls short” line. Ratings from fewer than 20 reviews say little: Vapi has 3 reviews on G2, Bland AI 11, PolyAI 12 and Cognigy 13.

What Retell AI does

Retell AI is a platform for developers and operations teams who build their own AI phone agents, for inbound and outbound calls, and secondarily chat and SMS agents. Agents built as a prompt, a conversation flow or with the Conductor copilot transfer calls, book appointments, send SMS and call any API mid-call. Retell bills voice per call minute from separate components (voice engine, voice, LLM, telephony and add-ons) at $0.07 to $0.31 a minute, with no platform fee and every feature on pay as you go. It started in Y Combinator in November 2023 and reported $80M in annualized revenue in September 2026.

Why teams look beyond Retell AI

Five components on every minute

Retell AI prices a call minute as the sum of its parts: the Retell Voice Infra engine at $0.055 a minute, a text-to-speech voice from $0.015, an LLM priced per model, telephony by country and add-ons for knowledge bases, denoising and PII removal (Retell AI pricing). The $0.07 to $0.31 headline is not a cap: GPT 6 Astra alone costs $0.32 a minute and Philippines telephony $0.8. Finance teams forecasting a support budget have to model each component.

No human agent inbox

Retell’s platform has no shared inbox for human agents. A voice agent hands over by transferring the call to a phone number or SIP destination, and Zendesk is reached as a tool that updates tickets, not as a place the agent runs. A support team needs its own helpdesk or contact center behind Retell.

Chat channels you connect yourself

Retell’s chat agents run in its website widget, over two-way SMS and through a chat API. WhatsApp, Messenger and other chat platforms have no built-in integration: a team connects them itself through the chat API (Retell chat agent docs). SMS works only on US numbers that passed A2P registration, which takes 2 to 3 weeks.

Built for developers to assemble

Retell gives developers the parts: prompts, conversation flows, custom functions, webhooks and SIP. Testing bills at production rates, and there is no free sandbox beyond the $10 signup credit. A support operations team without engineering time builds less on its own than a developer team does.

No services in the EU

Retell states that it does not operate services within the European Union, and claims GDPR through AWS’s data processing agreement (Retell compliance docs). Retell-managed phone numbers are US and Canada only, so callers elsewhere need custom telephony.

Two kinds of Retell AI alternatives

Two kinds of product get called Retell alternatives, and they solve different problems.

• Voice infrastructure for developers who build their own voice agents: an API or builder and per-minute billing, with the team supplying the prompts, integrations and what sits behind a transfer. Vapi, ElevenAgents (ElevenLabs), Bland AI and Synthflow belong here, as does Retell. Each takes actions during calls through tools and APIs, and none has a helpdesk inbox: a transfer goes to a phone number, a SIP destination or a contact center platform.
• Support products that include voice: a finished AI agent for a support operation, where voice is one channel among several and the agent hands over to a human team. Robylon, PolyAI and Cognigy belong here, and all three act in other systems. Robylon runs standalone with its own inbox or inside the helpdesk a team already uses; PolyAI and Cognigy sit in front of enterprise contact centers on NiCE CXone, Genesys Cloud, Five9 and Amazon Connect.

For developers replacing Retell like for like, Vapi is the closest match: per-minute API billing with your own transcriber, model and voice providers. ElevenAgents is the answer when voice quality and price per minute matter most. A support team whose phone line is one channel among several is choosing from the second group, where the split between chatbots and voice agents matters less than one agent and one inbox covering both.

How we compared the tools

We read each vendor’s pricing page, documentation, changelog and compliance pages on 7 and 8 October 2026, and each tool’s G2 page the same days. Where a vendor publishes no price, the table says so rather than estimating one. We did not run hands-on call tests for this page.

We compared them on what the AI agent can resolve, channels covered, where each runs, billing model, setup effort, and how each works for support agents and team leads.

The 7 best Retell AI alternatives

1. Robylon

Best for: support teams that want phone calls answered by the same AI agent that handles chat, email and WhatsApp, with a human inbox behind it, rather than a voice API to build on.

What it is for: Robylon is an AI customer support platform that resolves tickets across email, chat, voice and WhatsApp. It works standalone or alongside an existing helpdesk. Its agents take the action a ticket or call needs, acting through tools built from your APIs and connected apps and handing anything they cannot finish to a person with the checking already done. Every channel runs from one setup with the same knowledge base, and Robylon fits the stack you already run, inside your helpdesk or standalone. A lending customer recovered about 25% more collections with Robylon’s voice agents.

What the AI does:

• A voice agent is built in the same dashboard as the chat and email agents: you pick the speech to text provider (Deepgram, Google, Sarvam, Soniox or ElevenLabs), the LLM and a text to speech voice, and connect numbers through Twilio or Exotel.
• On a call, the agent can end the call, wait when asked, detect voicemail, hand the call to your team, search the knowledge base, send a WhatsApp template and press keypad tones (voice agent functions).
• Agents call tools built from your APIs and from 32 pre-built integrations, among them Shopify, HubSpot and Salesforce, to look up an order or update an account mid-call. Custom API integrations are on the Business plan.
• Post-call analysis extracts the details you define from every call and runs a workflow when it ends; outbound calls start from the API or a workflow, in bulk.

Channels: email, website and in-app chat, voice, WhatsApp, Instagram, Facebook, SMS through Twilio, YouTube comments, and reviews on Google Play, the App Store and Google My Business (channels page). Robylon runs standalone with its own inbox and optional human seats, or inside Freshdesk, Zendesk, Zoho Desk, Salesforce, Vtiger and Gorgias tickets and inside Intercom, Freshchat, SalesIQ and Zendesk messaging chat; inside Gorgias it covers email and chat. Voice phone calls and the Freshdesk, Zendesk, Zoho Desk, Intercom, Freshchat and Gorgias integrations start on the Business plan; WhatsApp and email start on Pro.

Pricing: by AI credits rather than per minute (see pricing). Starter is free with 300 credits a month (about 40 conversations) and covers chat only; paid plans start at $25 a month for 500 credits; voice phone calls start on Business, from $180 a month; yearly billing takes 10% off. Voice calls use credits at a rate the pricing page does not publish. Human seats are optional, at $19 to $89 per seat a month. G2 rating: 5.0 from 42 reviews (G2, October 2026).

Where it falls short: Robylon is not a developer voice platform. It publishes no per-minute voice rate, and voice phone calls start on the Business plan at $180 a month. Phone numbers run on Twilio or Exotel, or on your own carrier through SIP trunking, and answering inbound calls on a number is switched on by Robylon’s team on request. Credits per call vary with the AI model chosen.

Where Retell AI does better:

• Published per-minute pricing: every component of a call minute is listed, with no platform fee.
• Telephony reach: SIP trunking to Twilio, Telnyx, Vonage, Avaya, Genesys Cloud, Five9 or any SIP provider, plus Retell’s own US and Canadian numbers.
• Model choice on calls: OpenAI, Anthropic and Google LLMs, OpenAI realtime speech-to-speech models and a custom LLM over WebSocket, each priced per minute.
• Call center tooling: live call monitoring with whisper and takeover, and agentic warm transfer, where the AI briefs the human first.
• Self-serve voice: $10 in free credits and every feature on pay as you go; Robylon’s free Starter plan has no voice.

Pick it if: you run a support team and want calls, chat, email and WhatsApp answered by one AI agent that acts in your systems, with a human inbox or your helpdesk behind it. Choose Retell AI if you are building a voice product and want per-minute pricing, SIP trunking and your own choice of every model.

2. Vapi: best like-for-like Retell replacement

Best for: developers replacing Retell like for like, who want per-minute API billing and their own choice of transcriber, model and voice for each agent.

Vapi supplies orchestration, telephony and monitoring for voice agents built through its API, SDKs and dashboard. Each assistant picks its transcriber, model and voice, or the team brings its own provider keys and Vapi charges only hosting. Squads chain specialised assistants with handoffs that keep context; Vapi retired its visual Workflows builder on 18 August 2026 in favour of Squads (Vapi migration docs). Each organization runs in a US or an EU region.

What the AI does: answers and takes actions on every package. Built-in tools transfer calls (blind, warm, or warm with an assistant briefing the human), end calls, send SMS through Twilio, press keypad tones and make API requests; function tools call your server, a query tool searches a knowledge base, and MCP tools connect other systems. Prebuilt integrations cover Google Calendar, Google Sheets, Slack and GoHighLevel.

Channels: inbound calls on free US Vapi numbers; inbound and outbound calls on imported Twilio, Telnyx and DIDWW numbers; SIP trunks; web calls; a web widget with voice and text chat; and a chat API. SMS runs through your own 10DLC-approved Twilio number.

Pricing: per minute, a $0.05 hosting fee plus transcriber, model, voice and transport costs passed through with no markup; Vapi’s own calculator default comes to $82 to $129 for 1,000 minutes. Core costs $29 a month for support and limits, Pro is 10% of hosting fees with a $999 a month minimum, and the HIPAA add-on is $2,000 a month per organization (Vapi pricing). G2: 3.0 from 3 reviews (G2, October 2026).

Where it falls short: no helpdesk inbox: a handover is a call transfer, and neither the pricing page nor the billing docs say how minutes are billed after one. HIPAA costs $2,000 a month per organization on top of usage, free Vapi numbers are US-only and inbound-only, and SSO needs the Premier package.

Pick it if: you are a developer replacing Retell like for like and want per-minute billing, your own provider keys and an EU region.

3. ElevenAgents (ElevenLabs): best for voice quality

Best for: teams for whom voice quality and price per minute matter most, building voice and chat agents on ElevenLabs’ own speech models.

ElevenAgents is ElevenLabs’ agent platform, sold as Conversational AI and then Agents Platform before its February 2026 rename. New agents use the Eleven v4 Turbo voice model by default, and a visual Workflow Builder is on every plan, the free one included. ElevenLabs announced FedRAMP 20x Class A certification covering ElevenAgents on 1 October 2026.

What the AI does: answers and takes actions on every plan through webhook, client, code and MCP tools. System tools end calls, switch language, transfer to another agent or to a phone number or SIP URI, press keypad tones and detect voicemail. Integrations act on Zendesk and Freshdesk tickets, Intercom conversations and Salesforce Service Cloud cases.

Channels: web widget, mobile SDKs, WhatsApp messages and calls, and text-only chat. Phone calls run through your own Twilio number or SIP trunk, SMS through Twilio, and email only as replies through helpdesk integrations.

Pricing: $0.08 a call minute on every plan, with subscriptions that prepay minutes at that rate: Free with 15 minutes a month, Starter at $6 for 75 minutes, Pro at $99 for 1,238, Scale at $299 for 3,738 and Business at $990 for 12,375. LLM usage is billed separately by model, and your carrier bills telephony (ElevenAgents pricing). G2: 4.5 from 1,250 reviews (G2, October 2026), the ElevenLabs company listing, which covers all of its products.

Where it falls short: the LLM cost sits on top of the $0.08 minute, and ElevenLabs’ pages offer no phone numbers for sale, so telephony comes from your own carrier. A HIPAA business associate agreement is Enterprise only, and the Zendesk, Intercom and Freshdesk integrations do not support the Zero Retention Mode HIPAA use requires.

Pick it if: voice quality and price per minute matter most, and you have a Twilio account or SIP trunk to bring.

4. Bland AI: best bundled per-minute rate

Best for: enterprises in regulated, high-volume phone operations (healthcare, insurance, financial services, logistics, government) that want one per-minute rate on Bland’s own models.

Bland runs its own speech-to-text, language and text-to-speech models, with no third-party AI provider in the call path, and deploys in its cloud, your own VPC, on premises or air-gapped. It achieved FedRAMP 20x Class A on 25 August 2026.

What the AI does: answers and takes actions on every plan through tools that call any HTTP endpoint and integrations for Cal.com, Salesforce and Slack. Warm and live transfers, the scheduling node and in-call SMS are Enterprise features.

Channels: phone calls on Bland numbers and a web voice agent; SMS, RCS, iMessage and web chat on Enterprise; your own Twilio numbers; SIP trunks with the Enterprise SIP entitlement.

Pricing: per connected minute, with the LLM and speech included. Start has no platform fee and costs $0.14 a minute plus $0.05 a transfer minute; Build costs $299 a month plus $0.12 a minute; Enterprise is quoted (Bland AI pricing). Outbound attempts on Bland’s telephony carry a $0.015 minimum (Bland billing docs). G2: 5.0 from 11 reviews (G2, October 2026).

Where it falls short: Start caps at 100 calls a day and 10 concurrent calls, and warm transfers need Enterprise. Bland’s own pages describe telephony three ways, so check that line of any quote.

Pick it if: you run regulated phone operations and want one bundled rate and deployment in your own cloud or on premises.

5. Synthflow: best for no-code contact centers

Best for: contact centers, BPOs and agencies that want voice agents built without code and can sign an annual contract.

Synthflow builds voice agents in a no-code Flow Designer or Prompt Builder and places them inside contact center telephony (Freshcaller, RingCX, Five9, Genesys Cloud, Zoom, 8x8 and other SIP systems), where calls hand over to human agents. Since 25 August 2026, accounts without an Enterprise contract run on Synthflow’s own LLM only.

What the AI does: answers and takes actions during calls: transfers, HTTP and MCP actions, real-time booking in Cal.com and GoHighLevel, SMS or WhatsApp messages mid-call, post-call SMS and email, and keypad navigation. Native links create Freshdesk tickets and log HubSpot calls.

Channels: phone calls on Synthflow numbers, your own Twilio account or SIP on Enterprise; WhatsApp Business calling; web voice and chat widgets; a chat API. WhatsApp messaging and SMS need your own Twilio account in a US-region workspace.

Pricing: per minute inside a sales-led annual agreement, from $30,000 a year, with the rate set per contract (Synthflow pricing). The only published rate is a $400 a month plan with 2,000 minutes, sold only through the Freshworks Marketplace (Synthflow Freshworks docs). G2: 4.5 from 1,015 reviews (G2, October 2026).

Where it falls short: the self-serve Pro, Growth and Agency plans are no longer sold, so a direct customer cannot start without a contract, and calls are capped at 40 minutes. There is no human agent inbox.

Pick it if: you want no-code voice agents inside an existing contact center or agency setup, at a volume that justifies an annual contract.

6. PolyAI: best for enterprise inbound calls

Best for: enterprise contact centers in hospitality, restaurants, financial services and banking, healthcare, insurance, retail, telecom, travel, utilities and consumer services that want voice agents to resolve complex inbound calls.

PolyAI names Marriott, Caesars Entertainment, PG&E, UniCredit and FedEx among its customers. Agents are built in Agent Studio, also called Dialog Studio, and run on PolyAI’s Raven LLM by default or on OpenAI and Amazon Bedrock models. Self-serve sign-ups opened on 18 May 2026, but enterprise use runs on a contract.

What the AI does: answers and takes actions through Python tools, API integrations and MCP servers, covering authentication, account management, billing and payments, bookings, order management, troubleshooting, call routing and FAQs. Built-in actions work on Zendesk tickets, Salesforce cases, Epic appointments and OpenTable reservations.

Channels: voice, web chat, SMS, RCS, email, and in-app chat and voice through iOS and Android SDKs. Voice connects to SIP trunks, Five9, NICE CXone, Amazon Connect, Genesys Cloud, Zendesk Talk, Dialpad, Zoom and Twilio.

Pricing: per minute, rate not published, with maintenance and 24/7 support included; numbers bought through PolyAI cost 1.5 cents a minute (PolyAI pricing). G2: 5.0 from 12 reviews (G2, October 2026).

Where it falls short: quote only, with no published self-serve limits. The default Raven 3.5 model covers 24 of the 73 response languages in PolyAI’s docs; the rest need a third-party LLM (PolyAI language docs). Several integrations are managed services set up by PolyAI’s team.

Pick it if: you run a large inbound phone operation and want the vendor’s team to deliver and maintain the voice agent with you.

7. Cognigy: best for CCaaS contact centers

Best for: large enterprise contact centers, many on NiCE CXone or Genesys Cloud, that want voice and chat AI agents in front of the platform their human agents already use.

NICE closed its acquisition of Cognigy on 8 September 2025, and Cognigy sells both standalone and inside NiCE CXone. Voice runs through Cognigy Voice Gateway, a separately licensed product, and one agent can switch between LLM-driven turns and rule-based flows within a single call. Lufthansa Group, Toyota and DHL are among its named customers.

What the AI does: answers and takes actions. Agents get Jobs with Tools that call APIs, fetch data, start workflows or hand over, with 110+ prebuilt tools and integrations plus MCP. Answering from documents needs Knowledge AI, a separate licence.

Channels: voice over SIP through Voice Gateway, web chat, WhatsApp, Facebook Messenger, LINE, Microsoft Teams, Slack and Workplace from Meta; SMS through Twilio. Handover goes to NiCE CXone, Genesys Cloud, Salesforce Service Cloud, RingCentral Engage or 8x8.

Pricing: standalone licences bill per conversation of up to 50 user inputs within 24 hours, with voice by packages of concurrent Voice Gateway lines; NiCE CXone counts up to 10 minutes per call. Every price is quoted, and there is no pricing page (Cognigy billing docs). G2: 4.6 from 13 reviews (G2, October 2026).

Where it falls short: human-agent turns that pass through Cognigy count toward a billable conversation, so escalations are still charged. Live Agent, Cognigy’s own agent workspace, gets only security updates and bug fixes, so a contact center platform has to sit behind it.

Pick it if: your contact center runs on NiCE CXone or Genesys Cloud and some calls must follow fixed, auditable flows.

Alternatives by situation

What to decide before switching

Actions versus answers

Count what share of your calls need the agent to act in another system (a booking, an order lookup, an account change) rather than answer from help content. Every tool here can act mid-call; the difference is who builds the action. On Vapi, ElevenAgents and Bland AI your developers write the functions; Synthflow offers prebuilt booking and CRM actions; Robylon connects your APIs and 32 pre-built integrations; PolyAI and Cognigy build integrations with you under contract.

Channels your customers use

List the channels your customers use, not only the phone. If voice is the whole job, the developer platforms fit. If the same customers also write on chat, email and WhatsApp, an agent per channel means separate knowledge and separate handover rules. Robylon runs every channel from one setup; PolyAI covers voice, web chat, SMS, RCS and email; ElevenAgents adds WhatsApp; Vapi adds a chat API, and Bland AI adds SMS and web chat on Enterprise.

Where your team works

Decide where a transferred call lands. On Retell, Vapi, ElevenAgents, Bland AI and Synthflow, a transfer goes to a phone number, a SIP destination or a contact center platform, so the human team needs one already. PolyAI and Cognigy hand over into enterprise contact centers on NiCE CXone, Genesys Cloud, Five9 and Amazon Connect. Robylon hands over to its own inbox, where human agents can also phone customers, or runs inside the helpdesk the team already uses.

Pricing at your volume

Voice bills per minute, so compare tools on your real call minutes. The example assumes 1,000 inbound support calls a month averaging 4 minutes (4,000 call minutes) and excludes telephony unless stated, because most of these tools bill it through your own carrier.

The LLM is inside the Retell, Vapi and Bland AI figures but billed on top for ElevenAgents, so that figure rises with the model you pick. Robylon is not priced because voice calls use credits at a rate its pricing page does not publish. PolyAI and Cognigy are quote only.

When to stay on Retell AI

• You are building a voice product and want per-minute pricing with no platform fee to pass on to your own customers.
• You want to choose the LLM, the voice and the speech-to-speech model per agent, or run your own LLM over WebSocket.
• You need Retell’s documented connections into Genesys Cloud, Five9 or Avaya.
• Your team relies on live call monitoring with whisper and takeover, or agentic warm transfer.
• You need a self-signed HIPAA business associate agreement at no extra fee, which Retell offers on pay as you go.
• Your agents already run in production on Retell, and rebuilding them would cost more than the change saves.

What usually drives a switch is the shape of the work: a developer team wanting other provider control moves to Vapi or ElevenAgents, a contact center wanting a vendor-built agent moves to PolyAI or Cognigy, and a support team whose phone line is one channel among several moves to a support product. If none of those applies, Retell is a strong place to stay.

Moving off Retell AI

1. Baseline calls a month, minutes per call, transfer rate, call success rate and cost per call from Retell’s call analytics.
2. Export each agent’s prompt or flow, custom functions, knowledge bases and post-call extraction fields.
3. Decide where your numbers live: with your carrier over SIP, ported, or on the new tool’s telephony.
4. Decide where transferred calls land: the current contact center, a helpdesk, or the new vendor’s inbox.
5. Rebuild the top call intents first and test them against past transcripts.
6. Move one number or one queue while Retell handles the rest.
7. Compare call success, transfer rate and cost per call with the baseline, then move the remaining numbers.
8. Keep Retell numbers and credits live for 30 days in case you need to roll back.

Choosing a Retell AI alternative

Retell AI is one of the strongest platforms for building AI phone agents: every per-minute component is published, there is no platform fee, and developers choose the LLM, the voice and the telephony. For a developer team building a voice product it remains a sound choice, and Vapi and ElevenAgents are the like-for-like options when provider control, or voice quality and price per minute, matter more.

Move to a different kind of tool when the phone line is part of a support operation rather than a product. PolyAI and Cognigy suit enterprise contact centers buying through sales, Synthflow suits no-code voice agents on a contract, and Bland AI suits regulated operations that want one bundled rate. Robylon suits support teams that want one agent to take the action a call needs, run every channel from one setup and fit the stack they already run; its Starter plan is free to try.