# How Speko uses Cartesia

As published on [cartesia.ai](https://www.cartesia.ai/customers/speko), July 2026. Captured by usedby on 2026-10-08.

- Company: [Speko](https://www.usedby.ai/companies/speko.md)
- Tool: [Cartesia](https://www.usedby.ai/tools/cartesia.md)

## What the story says

Speko runs a voice AI router that benchmarks speech-to-text, LLM, and text-to-speech models and routes each call to the best stack. Cartesia's Sonic 3.5 is one of the text-to-speech models it tracks, and it leads Speko's text-to-speech ranking and is its most frequent recommendation.

Summary written by usedby from the source page, in English. The figures are those of Cartesia and Speko, not ours.

> Sonic 3.5 leads Speko’s overall text-to-speech ranking, with the strongest combination of speed and naturalness, and it holds up on price against the other models Speko tracks.

> We are building an open router of voice AI basically. We are trying to be this neutral layer where we help people to pick the right model stack.
>
> Beknazar Abdikamalov, Founder, Speko

## What usedby checked

We compared the story with its live page on 2026-10-08.

- Checked: the passage quoted above is copied word for word from the page, near the name of Speko.
- Checked: each number in our summary is printed on the page.
- Checked: the publication date is read from the page’s own metadata, never guessed.
- Checked: Speko uses Cartesia. Confirmed line. Latest check across sources: 2026-10-08.
- Not checked: the result itself. We quote it; we did not measure it.

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Source: https://www.usedby.ai/case-studies/speko-cartesia · How we check: https://www.usedby.ai/methodology