Does Open replace Twilio?

No. Open uses Twilio (or another carrier) for the telephony. Open replaces the agent runtime you'd otherwise build on top of Twilio.

Can I keep my Twilio numbers and trunks?

Yes — and most customers do. Open is a SIP destination on your existing Twilio configuration. No porting, no migration. Carrier minutes stay billed by Twilio with no markup from Open.

How does Open compare to Twilio AI Assistants specifically?

Twilio AI Assistants is a productized agent layer for Twilio-centric flows. Open's integration depth (CRM, calendar, EHR, dispatch, helpdesk) is broader, and the observability is deeper. For complex business deployments, Open is a more complete product; for simple Twilio-only flows, AI Assistants can be enough.

How does Open compare to ConversationRelay?

ConversationRelay is the primitive that connects an LLM to a Twilio call. It's a developer building block. Open is the finished product that uses that kind of primitive (under the hood) and adds the integrations, observability, and configuration on top.

Can engineering teams still build on Twilio if they need to?

Yes — Twilio's developer platform is excellent for that. We respect the build path; we just sell to a different buyer (ops teams who want to deploy, not build).

How fast is the migration from a Twilio-built agent to Open?

Days to a couple of weeks depending on how complex the existing agent is. Most Twilio-built agents move to Open when the maintenance burden of the custom build outweighs the differentiation.

Comparison

Open vs. Twilio

Twilio is the carrier and SIP layer. Open is the voice agent that runs on top of it. They're complementary — Open uses Twilio (or any other carrier) under the hood.

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Twilio: Telephony
Open: Agent
Twilio path: Build
Open path: Deploy

01 — Overview

Open or Twilio: which is right?

Twilio is the carrier and developer platform: SIP trunking, programmable voice, AI primitives (ConversationRelay, AI Assistants). Open is the voice agent product that runs on top of Twilio (and Vonage, RingCentral, BT, Telstra, etc.). Most Open customers use Twilio for the telephony and Open for the agent — the question is rarely "either-or".

Twilio is the most-used CPaaS in the world for a reason. The platform is excellent: SIP trunking that just works, programmable voice with TwiML, the ConversationRelay product for connecting LLMs to phone calls, AI Assistants for orchestrating tools. If you're an engineering team building voice products, Twilio is often what's underneath.

But Twilio is infrastructure with developer primitives, not a finished voice agent. To deploy a production voice AI on Twilio's primitives, you build the rest: the LLM-orchestration logic, the tool-calling, the integrations to your CRM / calendar / billing / helpdesk, the observability, the compliance plumbing, the configuration UI for your ops team. That's months to a year of engineering plus ongoing maintenance.

Open is a finished agent. Open uses Twilio (and Vonage, RingCentral, BT, Telstra, etc.) for the carrier and SIP layer — your numbers stay on Twilio, your minutes stay billed by Twilio. What Open adds is everything above that: the agent runtime, the integrations, the dashboard, the analytics, the compliance.

When the comparison is really "Twilio + ChatGPT API + LangChain + your engineering team" vs Open: the build path is cheaper at infinite scale and more customisable; Open is faster, includes the integrations, and is priced per outcome instead of per primitive. Most non-engineering buyers pick Open. Most voice-AI startups pick the build path.

When the comparison is really "Twilio AI Assistants" vs Open: AI Assistants is Twilio's productized agent layer, narrower in scope than Open. It's good for simple Twilio-centric flows; Open's integration depth (CRM, calendar, dispatch, EHR, helpdesk) and observability are deeper. The two products are co-evolving.

Twilio gives you

Carrier-grade telephony
SIP trunks, programmable voice, global PSTN, the works. Industry-standard infrastructure.
Developer primitives
TwiML, Voice API, ConversationRelay, AI Assistants — building blocks for voice products.
Pay-as-you-go pricing
Per-minute carrier pricing plus per-primitive AI costs.
Build it yourself
Maximum control. You own the agent, the integrations, the deployment.

Open ships

A finished voice agent
Configured in a dashboard, not built in code. Production-ready out of the box.
Native integrations
CRM, calendar, billing, helpdesk, dispatch — wired in. Not your job.
Production observability
Per-call recording, transcript, reasoning trace, outcome tag, cost-per-resolution.
Per-resolution pricing
Pay when the AI resolves something. Carrier minutes stay billed by Twilio.

02 — Why it works

What makes Open the right comparison answer

Open uses Twilio (or any carrier)
Your Twilio numbers stay on Twilio. Open registers as a SIP destination — no porting, no carrier change.
Skip the agent build
The 6-12 months of engineering between Twilio's primitives and a deployed agent — Open has done it.
Carrier-agnostic by design
Open works with Twilio, Vonage, RingCentral, BT, Telstra, Bell, and any standards-compliant SIP trunk. No lock-in.
Outcome-based pricing
Pay per resolved conversation, not per primitive. Carrier costs stay separate and unmarked-up.

03 — Security

Encrypted, audited, refundable

SIP over TLS for signaling, SRTP for media. Every call logged with full reasoning traces. SOC 2 Type II, GDPR-aligned, HIPAA- and PCI-ready. Backed by the Open $2M Refund Guarantee.

04 — FAQ

Open vs. Twilio questions, answered

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