Omnia Voice vs Retell

Retell positions itself explicitly as a voice agent platform for phone call centres, and it is good at that. If what you have is a call centre and what you want is to automate parts of it, that focus is a feature, not a limitation.

Omnia is a platform you build on. The difference is less about capability than about who is expected to do the assembling.

Choose Retell if

• You are automating an existing call centre and want something shaped for that
• You want workflows, dashboards and agent management out of the box
• Your operation runs in English
• You would rather buy a product than build on a foundation

Choose Omnia if

• You are building a product, not automating a call centre
• You want one system with a forecastable cost, not a per-component bill
• You need the agent embedded in your application — a web app, a mobile app, your own telephony — rather than in a platform's console
• You want to run it on your own infrastructure

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Product or platform

This is the real fork.

Retell gives you a call centre shaped thing. That is genuinely faster if your problem is call-centre shaped.

Omnia gives you an API, an SDK, tools that call your systems, and a WebSocket you can bridge to anything. It expects you to build the product. That is slower on day one and better on day ninety, if what you are making is not a call centre.

If you are an agency deploying voice for clients — as several of ours are — this matters. You are building something to hand over, not adopting something to operate.

One system, not an assembly

Omnia connects audio directly to the reasoning layer. There is no speech-to-text stage in the middle, which is where the round-trip time goes and where nuance gets dropped. One design decision, two consequences worth having:

Speed. About 250 milliseconds to first response, because processing starts while the caller is still speaking rather than after a transcript is finished.

Robustness. Accents, proper nouns, and callers who switch language mid-sentence survive, because there is no transcription step to flatten them first. That is what 50+ languages means in practice — not a list on a pricing page, but comprehension over a narrowband phone line, at conversational pace.

Agents that act

An agent that talks well and cannot do anything is an answering machine. Ours call your systems mid-conversation, with credentials encrypted at rest and never returned by the API, static parameters the model never sees, read-only lookups run eagerly so they do not become dead air, and a deferred pattern for work that cannot finish inside a timeout without stranding the caller.

Language, as a consequence

Retell operates primarily in English. Their own comparison content is translated into a dozen languages; the agents are a separate question.

Omnia holds a conversation in 50+ languages, with real depth in the Nordic languages and Spanish. Language is detected rather than declared, and an agent switches mid-call because the caller did — not because it was configured to.

Cost

Omnia charges one rate for the AI:

Speech recognition, reasoning and speech synthesis in a single number.

The first two rates are self-serve: sign up and start. The volume rate is negotiated rather than unlocked automatically, so talk to us if you are running at scale.

Telephony is your own. Bring Twilio, Telnyx, Setera or an existing SIP trunk and pay them directly. We do not resell your phone bill or mark it up.

Where it runs

Cloud, dedicated GPU capacity, or entirely your own infrastructure — the same API across all three, so moving does not change your integration code. EU data residency is the default rather than a configuration.

Self-hosting is also an exit route, not only a deployment preference. If we were acquired, pivoted, or sunset a service, a self-hosted customer keeps running. You cannot be orphaned by us.

Side by side

The honest summary

If you run a call centre, Retell is shaped for you and Omnia will feel like building. If you are making something — a product, a client deployment, an agent inside your own app — and especially if your callers do not all speak English, that is the case for Omnia.