People who built or building voice agents immediately get this.

openrouter is the openrouter for audio models.

the conflation is "audio models" vs "voice ai", and the mental model that untangles it: think batch requests. text in, audio out (streamed, even). audio in, transcript out.

three questions inside the word "router":

1 - what gets picked: a model/voice, a provider of the same model, or the whole stack (stt + llm + tts) per call

2 - where it lives: an external http gateway, the agent platform (vapi/retell/livekit configs), or inside the live session

3 - when: session start, or mid-call

a voice agent is not a batch request. it's a live duplex session: turn-taking, barge-in, telephony legs, session state. the latency physics diverge too: a middleman hop in the media path is paid once by a batch request and on every conversational turn of a live call, so the media path wants a direct connection to the provider. a gateway that terminates at http can route the requests inside a call; it can't route the call.

OpenRouter isn't open source.

This isn't Stripe payments. The market will have lots of competitors.