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The Best Twilio Alternative for AI Agents

Deploy voice AI without building telecom infrastructure

Seamly is a managed telephony alternative to Twilio for teams deploying AI voice agents. Where Twilio gives you programmable building blocks (SIP, TwiML, webhooks) and asks you to operate the underlying voice infrastructure, Seamly delivers carrier connectivity, routing, monitoring, and EU hosting as a managed layer. Your team builds the AI agent. Seamly runs everything required to make it reachable by phone.

Two solutions, one challenge

As AI agents expand beyond chat and text-based interactions, voice quickly becomes the next logical step. At that point, most teams face a choice:

Build and operate their own voice infrastructure using a programmable CPaaS like Twilio
Use Seamly as a managed telephony infrastructure layer purpose-built for AI agents

Both approaches can support voice AI deployments. The difference lies in operational ownership, implementation complexity, and the amount of telecom expertise required to scale reliably.

Seamly

Managed telephony infrastructure for AI agents. Seamly turns AI agents into voice agents. It provides the complete telephony infrastructure layer required to deploy voice AI in production: carrier connectivity, number management, routing, monitoring, infrastructure operations, and partner support. Your AI agent handles the intelligence. Seamly handles everything required to make that intelligence reachable by phone.

Twilio

Programmable CPaaS Platform. Twilio provides highly customizable APIs for voice, messaging, and communications workflows. Teams can build custom voice experiences using programmable call flows, SIP capabilities, and infrastructure components.This gives engineering teams significant flexibility and architectural control, while also placing operational responsibility on the platform itself.

The core difference

The difference between Seamly and Twilio is not feature depth. It is ownership. Twilio is designed for teams that want to operate and customize their own voice infrastructure. Seamly is designed for platforms that want to deploy voice AI without becoming telecom operators.

Developer-centric voice infrastructure

Twilio provides programmable building blocks: SIP trunking, TwiML, programmable call flows and webhooks. This architecture gives engineering teams extensive flexibility to customize voice behavior and infrastructure.

It also means the platform itself becomes responsible for routing logic, failover handling, infrastructure monitoring, telecom operations and carrier management. For organizations with dedicated telecom and backend engineering teams, this model can make sense. For platforms focused primarily on orchestration and conversational intelligence, it often creates a parallel operational domain outside the core product.

Managed telephony infrastructure for AI agents

Seamly provides a production-ready telephony layer built specifically for AI voice deployments. Instead of exposing low-level telecom primitives, Seamly abstracts telecom infrastructure entirely. Carrier connectivity, number management, call routing, operational support and infrastructure are part of what Seamly provides.

Your platform remains focused on the AI agent experience itself. Seamly handles the infrastructure required to run voice reliably at scale.

Infrastructure ownership

Twilio provides the infrastructure foundation; you provide the engineering. Scaling, monitoring, incident response, compliance, number management: all of it falls within your scope.

This model offers architectural control, but operational complexity increases as deployments grow.

Managed end-to-end

Seamly delivers voice infrastructure as a managed service. Telephony infrastructure, number provisioning, carrier relationships, SLA monitoring, and dedicated partner support are all included. You don't build toward a voice product, you start with one.

Every new deployment runs on the same managed infrastructure layer without requiring additional telecom operations from your internal team.

From text-based AI to voice AI

For many AI agents, the challenge is not simply adding telephony. The real challenge begins after the first phone call. Voice interactions introduce operational and conversational complexity that simply doesn’t exist in text-based environments.

interruption handling
latency management
turn-taking behavior
fallback routing
real-time orchestration
call reliability

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 operating in European markets, infrastructure location increasingly matters for:

data residency requirements
procurement processes
enterprise governance
operational trust
GDPR-sensitive deployments

Twilio operates globally with infrastructure choices varying by setup and configuration.

Comparison overview

	Seamly	Twilio
Technical model	Managed infrastructure layer	Programmable API’s
Operational ownership	Managed by Seamly	Managed internally
Time to first production call	Days to a few weeks	Weeks to months
Required expertise	Integration & AI focus	Telecom & backend engineering
Infrastructure management	Included	Internal responsibility
Multilingual support	110+ languages via real-time translation included	DIY via STT/TTS provider choice
Scalability	Scales without added overhead	Scalable operations grow with you
From text to voice AI transition support	Included	Self-managed
Support model	Dedicated partner support	Documentation & support tickets
Speech engines	Best-in-class STT/TTS integrated, including voice cloning	Bring your own or use Twilio's, billed per provider
Hosting	Fully EU built & hosted	Global, configuration dependent

Predictable pricing for unpredictable call volumes

Twilio pricing is usage-based and typically expands as additional voice capabilities are introduced. Speech recognition, voice synthesis, recordings, transcripts, and analytics are commonly billed separately, making operational forecasting more complex as deployments scale. Seamly uses a predictable pricing structure per voicebot call, including: speech recognition, voice synthesis, recording, transcripts, insights, and full EU hosting. No additional telecom components or infrastructure services need to be configured separately.

	Seamly	Twilio
Pricing model	Fixed price per voicebot call	Usage-based
STT	Included	Additional cost
TTS	Included	Additional cost
Call recording	Included	Additional cost
Transcripts	Included	Additional cost
Advanced insights	Included	Additional cost
Hosteding	Fully EU hosted	Depends on deployment setup

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When to choose which?

The right choice depends on where you want to invest operational ownership. Here's an honest overview.

Choose Seamly when

You want to deploy voice AI without operating telecom infrastructure
Your focus is AI orchestration, customer experience, or agent intelligence
You want to move from text-based AI to voice quickly
Your team does not want to manage SIP routing, carrier operations, or telecom reliability
You want a managed infrastructure layer with dedicated support
European hosting and data residency matter to your customers

Choose Twilio when

Your engineering team wants full architectural control
You require highly customized telecom behavior or workflows
You already operate telecom infrastructure internally
You want direct ownership over routing, carrier integrations, and infrastructure logic
Long-term infrastructure customization outweighs operational simplicity

Frequently Asked Questions

What can I use instead of Twilio?

The alternative you choose depends on what you're trying to build. Twilio gives you the building blocks, with APIs for telephony, programmable voice, SMS, and developer documentation. You assemble and operate the voice stack yourself.

Seamly takes a different approach. We deliver a managed voice AI layer, with carrier connectivity, call routing, monitoring, EU hosting, and integrated STT and TTS, so your team focuses on the AI agent logic instead of the telecom plumbing.

If you're deploying AI agents that need to speak naturally, scale predictably, and run on European infrastructure, Seamly is built for that exact use case. Voicification (turning a chatbot or AI agent into a phone-ready experience) is what we do.

Who is Twilio's biggest competitor?

Twilio competes in several overlapping markets, and the strongest competitor depends on your needs. In CPaaS messaging, several developer-focused platforms compete on price. In contact-centre voice, traditional and cloud contact centre vendors dominate.

For voice AI specifically, the layer that turns AI agents into phone-ready experiences, Seamly is the practical choice for teams that don't want to build telephony infrastructure themselves. Seamly delivers managed connectivity, EU hosting, and integrated speech engines as a single layer on top of your AI agent.

The right comparison depends on whether you're building voice infrastructure or deploying voice intelligence.

Does Twilio offer voice?

Yes. Twilio's Programmable Voice API lets developers make and receive calls, route them, and stream audio to other services. It's a foundation you build on, not a pre-built voice agent.

For an AI voice agent, the Twilio Voice API is one part of a longer chain. You also need an STT engine, a TTS engine, an LLM, latency tuning, interruption handling, and call orchestration. Each of those is your responsibility.

Seamly takes a different route. We hand you a managed voice layer with all of those components already integrated and tuned, so your team only configures the AI agent logic. Voicification is the goal: your AI agent answers the phone, and the infrastructure handles itself.

How much do AI voice agents cost?

The cost depends on how the underlying voice infrastructure is priced. Developer-focused platforms typically bill per second of call time, plus separate line items for carrier, STT, TTS, and any AI services. That gives flexibility, and it makes monthly costs harder to forecast, especially for long or unpredictable conversations.

Seamly uses a fixed per-call pricing model. Carrier connectivity, STT, TTS, and orchestration are included. Call length doesn't surprise the bill, and that's a deliberate choice. Voice AI agents often handle longer conversations than traditional IVRs, and unpredictable per-second costs hurt unit economics.

Beyond pricing, total cost includes the engineering hours you spend operating the infrastructure. Seamly's managed model removes that ongoing cost line entirely.

The real decision: build infrastructure or deploy voice AI

Twilio gives you the flexibility to build and operate voice infrastructure themselves.

Seamly removes that operational burden entirely and provides a managed telephony layer purpose-built for AI agents.

For platforms where voice is a capability to deploy rather than an infrastructure domain to own, that distinction becomes increasingly important as deployments scale.

Discover how Seamly helps platforms deploy voice AI without telecom complexity.

Talk to our partner manager Albert