Twilio vs Vonage vs Telnyx: voice agent for Dutch home-care

The operations lead at a regional home-care provider in Noord-Brabant pulled up her Excel sheet. 1,238 inbound calls yesterday. 1,156 the day before. The Monday spike hit 1,400. Three caregivers were dropping out of shifts because they were stuck on hold with planning. Family members of clients were calling at 22:00 because the night shift had not shown up and nobody answered. The phone tree had eight levels.

She wanted one number that would route, triage, take a sick-call, confirm a visit, and escalate the real emergencies to a human in under ten seconds. A voice agent. The kind that handles 80% of routine traffic and leaves the planners free to actually plan.

The question that landed on our desk: which voice API do we build on?

We benchmarked three. Here is the honest read.

The three contenders

Twilio is the obvious starting point. Largest carrier integrations, most documentation, mature SIP, and the Voice Intelligence and ConversationRelay products specifically aimed at AI agents. It has been the default since 2010 and most engineers reading this have written a TwiML response at some point.

Vonage (formerly Nexmo, now part of Ericsson) is the European-flavoured alternative. The Voice API uses Nexmo Call Control Objects (NCCOs), it has a strong EU footprint, and the pricing tends to come in under Twilio by 15 to 25% on inbound minutes. Documentation is thinner but the platform is solid.

Telnyx is the network-owner play. They run their own private IP backbone instead of leasing capacity, which translates into lower latency, lower per-minute cost, and a different posture on reliability. They have grown fast in the AI voice agent space because the economics work at scale.

All three offer Dutch numbers, all three support WebSocket media streams (so your speech-to-text and text-to-speech layer can do its job), and all three have programmable call control. The differences live in the details.

Pricing on EU inbound

The home-care provider needed Dutch geographic numbers and was looking at roughly 36,000 inbound minutes per month (1,200 calls per day, about one minute average, 30 days).

Approximate ranges as of mid-2026, per inbound minute to a Dutch geographic number:

• Twilio: roughly $0.0085 per minute, plus number rental.
• Vonage: roughly $0.0070 per minute.
• Telnyx: roughly $0.0045 per minute.

That looks small. Run the math: at 36,000 minutes a month, the spread between Twilio and Telnyx is about $144 a month, or roughly €1,650 a year. For one client, fine. For an agency running ten voice agents, real money. And the per-minute charge does not include the outbound legs when the agent transfers to a planner, or the media-stream charges if you route your audio through provider-side transcription.

Pricing moves. Check directly at Twilio, Vonage, and Telnyx before you commit.

Latency and the audio path

A voice agent feels alive or dead based on one number: time-to-first-token after the caller finishes speaking. Below 700ms and the caller thinks they are talking to a fast human. Above 1.2s and they start saying "hallo? hallo?". Above 1.8s and they hang up.

The audio path looks like this:

• Caller's voice hits the carrier.
• Carrier hands the SIP leg to the voice API provider.
• Provider sends a WebSocket media stream to your STT.
• STT transcribes. Your agent reasons. TTS speaks.
• Audio goes back through the WebSocket, through the provider, through the carrier, to the caller's ear.

Every hop is latency. The provider's network topology matters.

Telnyx hosts its own backbone with PoPs in Amsterdam and Frankfurt. From our Frankfurt-hosted agent runtime, we measured WebSocket round-trip to Telnyx at 12 to 18ms consistently. Twilio routed our test traffic via Dublin (their EU region), which added 28 to 35ms. Vonage routed via London, 22 to 30ms.

That is 15 to 20ms of headroom for the LLM. It does not sound like much. It is the difference between "natural" and "slightly off".

Dutch numbers and the carrier reality

All three offer Dutch geographic numbers and 088 service numbers. The difference is provisioning friction.

Telnyx asked for a Dutch address proof and got us a working 088 number in 36 hours. Vonage took five business days. Twilio took nine, plus two back-and-forth emails about KYC documentation that did not match what their portal asked for.

Porting an existing number is where this gets worse. Twilio port-in for a Dutch geographic number took us four weeks on a previous project. Telnyx promised two and delivered in eleven days.

For a home-care agency that has had the same 088 number on a billboard since 2014, this matters. You cannot ask them to change the number.

EU residency and the AVG

Home-care data is special category under GDPR (AVG in Dutch). You are processing health-related information about elderly clients. The Autoriteit Persoonsgegevens, the Dutch data-protection authority, has been increasingly active on this file since 2024.

What this means in practice:

• Call recordings must stay in the EU.
• The transcription path must stay in the EU.
• Your data processing agreement must be signed before the first call.

Twilio offers EU data residency, but you have to explicitly enable it and not every product is covered. Voice Intelligence in particular has limits. Vonage is EU-native and treats residency as the default. Telnyx offers EU regions and signs a clean AVG-compliant processing agreement without a fight.

All three are workable. The path of least resistance is Vonage or Telnyx. With Twilio you will spend two weeks reading compliance documentation and chasing the right contract addendum.

For deeper reading, the Autoriteit Persoonsgegevens publishes guidance specifically on processing health data.

What we shipped

We picked Telnyx.

The deciding factors, in order:

1. Latency. The 15ms gap was real and audible in side-by-side caller tests.
2. Pricing. At the agency's growth trajectory, the per-minute savings compound.
3. Provisioning speed. The 088 port window meant we could ship in two weeks instead of six.
4. Support. We hit a SIP REGISTER issue at 02:00 on a Saturday. A real engineer answered within eight minutes.

What we did not love: the dashboard is rougher than Twilio's, the documentation has gaps around advanced media-stream configuration, and the Node SDK ships with fewer batteries-included helpers. We wrote more glue code. It was worth it.

If we had been building for a US-based customer, the calculus would have been different. Twilio's Voice Intelligence and ConversationRelay stack genuinely shortens the path to a working agent in English. For Dutch traffic, with AVG residency and 088 portability, Telnyx is the cleaner shape.

When we built the voice agent for this home-care client, the thing we ran into was Dutch number portability across the provider switch. We solved it by running both providers in parallel for two weeks and progressively shifting inbound traffic, which kept the billboard number live the entire migration.

Before you pick a vendor, time one specific thing: from your planned runtime region, how long does a WebSocket round-trip to each provider's nearest media endpoint take? That single number tells you most of what you need to know.