A Retell AI alternative with a built-in knowledge base and flat pricing

Looking for a Retell AI alternative usually means one of two things: either the bring-your-own-everything model is more assembly than you wanted, or the per-component billing is harder to predict than you'd like.

Retell is a well-engineered platform built for developers who want to control each layer of the voice stack. That's a real strength — and for some teams, exactly right. This post is the honest side-by-side so you can tell whether that's you, or whether a more batteries-included platform fits better.

The one-screen comparison

Where Retell is the better choice

• You want to choose every component. If picking a specific STT model, a specific TTS voice vendor, and your own LLM is the whole point, Retell's composable design is built for that.
• You have an ML team that wants to tune the pipeline. The low-level access is a feature, not a chore, when you have the people to use it.

Where Call2Me wins

1. Flat pricing instead of a four-line invoice

Retell bills per component: STT + LLM + TTS + telephony each have their own rate, so a month's cost is a small spreadsheet. Call2Me is $0.10/min for the voice pipeline + $0.05/min when a phone number is involved — one number, one multiplication.

2. Knowledge base without assembling it

Call2Me ships pgvector RAG built in: upload your docs, the agent answers from them. With Retell you wire retrieval yourself. If "the agent should know our pricing and policies" is on your list, that's the difference between an afternoon and a checkbox.

3. White-label and self-host

Call2Me is multi-tenant white-label out of the box — resell under your own brand and domain. It's also open core, so you can self-host if you need to keep everything in your own infrastructure. Retell is a hosted, single-tenant platform.

4. Multilingual out of the box

Nine languages with localized prompts and voices, so non-English agents sound native.

Migrating from Retell

Same building blocks on both sides — prompt, voice, tools, webhooks, a SIP number — so the move is mechanical:

1. Paste your system prompt into a new Call2Me agent.
2. Pick a voice and language (no need to choose STT/TTS vendors separately).
3. Re-point your function/webhook handlers (same request/response shape).
4. Test free in the browser, then attach a number.

Run both in parallel and cut over when you're happy.

So which should you pick?

• Pick Retell if low-level, per-component control is the goal and you have the team to use it.
• Pick Call2Me if you want flat pricing, a built-in knowledge base, white-label reselling, multilingual agents, and a faster path from idea to live agent.