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The Best Retell AI Alternative for AI Agents

Add voice as a channel, without rebuilding your AI agent inside a separate voice-agent platform

Seamly is a managed voice infrastructure layer for platforms and system integrators that want to deploy AI agents over the phone. Retell AI is a dedicated voice-agent platform for building, testing, deploying and monitoring AI phone agents directly inside Retell. Both solutions help teams deploy AI agents over the phone. The difference is where the agent should live.

One key decision: agent platform or voice layer?

As AI agents move from chat and digital workflows into phone conversations, teams need more than a phone number. They need live-call orchestration, speech recognition, voice synthesis, routing, monitoring, call transfers and operational support.

At that point, there are two common routes:

Build the phone agent inside a dedicated voice-agent platform like Retell AI
Keep the existing AI agent layer in place and connect it to telephony through Seamly

Both routes can support real-time AI calls. The strategic difference is product ownership. Retell AI is strongest when you want a dedicated environment for creating AI phone agents from the ground up. Seamly is strongest when voice needs to become part of your existing platform or integration offering.

Seamly

Voice infrastructure for existing AI agents

Seamly turns existing AI agents into phone-ready voice agents. It provides the managed voice infrastructure needed for production deployments: carrier connectivity, number management, routing, STT, TTS, recordings, transcripts, insights, monitoring, support and EU hosting.

Your AI platform remains the agent layer. Seamly makes that agent reachable by phone.

Retell AI

Dedicated AI phone agent platform

Retell AI provides a platform to build, test, deploy and monitor AI phone agents. Teams can create agents, configure prompts or conversation flows, connect tools, use telephony options, test calls and monitor performance inside Retell.

Retell becomes the environment where the phone agent is created, tested and operated.

Where the difference starts

The difference between Seamly and Retell AI is less about whether both can support AI phone calls. Because they both can. The difference is the layer each product wants to own.

A complete workspace for building AI phone agents

Retell AI is designed as an end-to-end platform for AI phone agents. Retell supports prompt-based agents, conversation flow agents, playground testing, simulation testing, phone calls, custom telephony, webhooks and call analysis.

This gives teams a practical route from concept to live AI phone agent. A team can configure the agent, test call behaviour, and deploy inbound or outbound phone calls inside Retell.

That model works well when the voice agent itself is the product being built. For platforms that already have their own AI layer, Retell introduces a different architectural question: should the voice experience be built inside Retell, or should the existing platform remain the centre of the solution?

Managed voice infrastructure for your existing agent layer

Seamly is built for existing AI agent platforms. Your conversational agent remains in place. Seamly connects that intelligence to the phone channel.

Carrier connectivity, number provisioning, routing, speech recognition, voice synthesis, call transfers, fallback logic, recordings, transcripts, insights, monitoring and operational support are managed by Seamly.

There is no need to recreate your agent logic in a separate phone-agent builder. There is no need to manage SIP routing, carrier relationships or telecom reliability internally. That’s all done by Seamly.

Seamly runs the voice layer required to make AI agents work over the phone in production.

Build and operate inside a dedicated AI phone agent platform

Retell AI gives teams one environment for configuring and operating AI phone agents. That can be attractive when speed, experimentation and direct control over phone-agent behaviour are the main priorities.

This makes Retell a good fit for teams that want to create a standalone AI phone agent directly inside Retell, especially for use cases like appointment setting, lead qualification, reception, outbound calling and customer service automation.

The trade-off is that the voice-agent runtime sits inside Retell. For some teams, that is exactly the point. For organizations that already have an AI agent in place, it creates a separate layer between the customer and the current AI agent platform.

Add voice without changing where your product lives

Seamly is designed for platforms and system integrators that want to make their own AI agents available over the phone.

The agent layer remains yours. The customer workflow remains yours. The commercial packaging remains yours. Seamly manages the phone infrastructure, speech layer and production operations underneath it.

This matters when platforms want to stay focused on their core product. Partners need predictable pricing, operational support and a deployment model that fits into their existing proposition. Seamly is built around that model.

From AI agent to phone-ready experience

Voice conversations are very different from text-based interactions. Callers interrupt the voicebot, they hesitate or they rephrase in the middle of a sentence. They speak with background noise and they expect immediate responses from the voicebot.

That means phone-ready AI requires more than a prompt and a voice. It requires:

turn-taking behaviour
latency management
interruption handling
fallback routing
call transfers
recordings and transcripts
carrier reliability
operational support when calls fail

Seamly supports platforms during this transition from text-based AI experiences to production-ready voice agents. We call this voicification. That includes both the telephony layer and the operational realities of deploying voice AI in real-world environments.

A 3D illustration showing a voice call on the left, and a written chat conversation on the right, with Seamly connecting the two in the middle.

European infrastructure by design

Seamly is fully built and hosted in Europe. For platforms and system integrators serving European markets, infrastructure location matters during procurement, vendor review and enterprise sales.

European hosting is especially relevant for:

data residency requirements
GDPR-sensitive deployments
enterprise governance
public sector and regulated markets
operational transparency

Unlike Retell AI, Seamly operates with a Europe-first infrastructure model from the start.

Comparison overview

	Seamly	Retell AI
Starting point	Existing AI agent, platform or partner proposition	New AI phone agent built inside Retell
Technical model	Managed voice infrastructure layer	Dedicated AI phone agent platform
Agent ownership	Your platform remains the intelligence layer	Agent behaviour is configured and operated inside Retell
Telephony	Carrier connectivity, routing and number management managed by Seamly	Retell phone numbers or custom telephony via SIP
Operational ownership	Managed by Seamly	Retell provides the platform; you configure agent setup and usage
Required expertise	AI orchestration, integration and customer experience	Voice-agent design, tool configuration and telecom infrastructure
STT and TTS	Included	Provider and configuration dependent
Multilingual support	110+ languages via real-time translation included	Configuration dependent
Support model	Dedicated partner support	Community and e-mail support on pay-as-you-go, enterprise support options available
Pricing model	Fixed price per voicebot call	Usage-based per minute
Hosting	Fully EU built and hosted	Retell states it does not currently operate services within the EU
Best fit	Platforms and system integrators adding phone to their own AI proposition	Teams building standalone AI phone agents in a dedicated environment

Usage-based pricing or predictable voicebot pricing?

Retell AI is transparent about its pricing. The pay-as-you-go plan lists AI Voice Agents at $0.07 to $0.31 per minute. Retell also publishes component-level pricing. CXosts follow usage, and teams can start without a large upfront commitment.

In production, the same model can make forecasting more complex. Voice AI calls vary in length. A short qualification call might take less than a minute. A complex call can take much longer. Model choice, voice provider, telephony setup and add-ons also affect the final cost.

Seamly uses a fixed price per voicebot call. Speech recognition, voice synthesis, recordings, transcripts, insights, infrastructure operations, support and EU hosting are included For platforms and partners, this makes pricing easier to package, quote and explain to customers.

	Seamly	retell ai
Pricing unit	Fixed price per voicebot call	Usage-based per minute
Main cost driver	Number of voicebot calls	Minutes, LLM choice, TTS choice, telephony setup and add-ons
STT	Included	Configuration dependent
TTS	Included	Component pricing depends on voice provider
Call recording	Included	Available through platform configuration
Transcripts	Included	Included in pay-as-you-go feature set
Advanced insights	Included	Available through analytics add-ons
Infrastructure operations	Included	Platform provided by Retell; agent setup remains with your team

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When to choose which?

The right choice depends on where you want the voice-agent layer to sit.

Choose Seamly when

You already have an AI agent, conversational platform or automation proposition
You want voice AI to become a managed channel underneath your existing product
You need a voice solution you can sell as part of your platform
You want predictable pricing per voicebot call
You don’t want to manage carrier operations, SIP routing and telecom infrastructure
EU hosting and data residency are important for you
You want dedicated partner support during rollout and scaling

Choose Retell AI when

You want to build the AI phone agent inside a dedicated voice-agent platform
You want a fast self-serve path for creating and testing phone agents
Your team is comfortable configuring prompts, flows, tools and call behaviour inside Retell
You prefer usage-based pricing tied to call minutes and selected components
You want to use Retell’s platform environment for build, test, deploy and monitor workflows
EU-only hosting is not a hard requirement
You want a direct platform setup with enterprise options available later

Frequently Asked Questions

What is Retell AI used for?

Retell AI is used to build, test, deploy and monitor AI phone agents. Its platform supports inbound and outbound calls, telephony, prompts, tools, analytics, testing and monitoring.

For teams that want to create AI phone agents directly inside a dedicated platform, Retell AI can be a practical option.

For platforms and system integrators that already have the conversational AI layer and want to add phone as a managed channel, Seamly is the more direct fit. Seamly provides the voice infrastructure underneath your existing agent.

What is the best Retell AI alternative?

The best Retell AI alternative depends on what you want to own.

If you want a dedicated platform to build and operate phone agents, Retell AI fits that category. If you already have a conversational AI platform and want to bring that agent to the phone, Seamly is a stronger fit.

Seamly does not require you to move agent logic or customer workflows into a separate voice-agent environment. Your platform remains the intelligence layer. Seamly manages the telephony, speech layer, routing, monitoring, support and EU hosting behind it.

How much does Retell AI cost?

Retell AI’s public pay-as-you-go pricing lists AI Voice Agents at $0.07 to $0.31 per minute. Retell also publishes component pricing for voice infrastructure, text-to-speech, LLMs, telephony and add-ons.

Seamly uses a fixed price per voicebot call. This is designed for platforms and partners that need predictable customer pricing, especially when call duration varies.

Is Retell AI EU hosted?

Retell AI states that it is GDPR compliant through AWS infrastructure with a GDPR-compliant Data Processing Addendum. Its compliance documentation also states that Retell does not currently operate services within the European Union.

Seamly is fully built and hosted in Europe. For European platforms, system integrators and enterprise customers with data residency requirements, this is an important distinction.

What is the difference between Seamly and Retell AI?

Retell AI is a dedicated platform for building, testing, deploying and monitoring AI phone agents. It is designed for teams that want to create and manage phone agents inside Retell.

Seamly is a managed voice infrastructure layer for platforms and system integrators. It connects your existing AI agent to the phone channel and manages the telephony, speech layer, routing, recordings, transcripts, insights, support and EU hosting.

In practical terms: Retell AI is where you build the phone agent. Seamly is how your existing AI agent becomes phone-ready.

Build inside a voice-agent platform or bring your own agent to voice

Retell AI is a strong option when the goal is to create AI phone agents from the ground up. Seamly is built for platforms where the AI agent already exists and want to bring it to the phone channel.

Discover how Seamly helps platforms deploy voice AI without telecom operational overhead.

Talk to our partner manager Albert