> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://developers.deepgram.com/llms.txt.
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## Update Nova-3 Keyterms Mid-Stream

Swap in the vocabulary for each step of a call without reconnecting. To replace a Nova-3 stream's [keyterms](/docs/keyterm) during a `/v1/listen` session, send a `keyterms` array in a [`Configure`](/docs/configure) message:

```json
{ "type": "Configure", "keyterms": ["Deepgram", "customer service"] }
```

Each `keyterms` array replaces the whole list, including keyterms set with the `keyterm` query parameter, and an empty array `[]` clears them. The 500-token [keyterm limit](/docs/keyterm#key-term-limits) that applies to the `keyterm` query parameter also applies to each update; an over-limit update returns an `Error` and leaves the stream's keyterms unchanged. The same message can also turn formatting features on or off, for example `"features": { "numerals": true }`.

Mid-stream keyterms work on every Nova-3 streaming model, including monolingual languages, multilingual (`language=multi`), and Nova-3 Medical, and they behave the same as keyterms set when you open the stream. Updating Nova-3 `keyterms` with `Configure` on `/v1/listen` is available on the global endpoint (`api.deepgram.com`). It isn't available yet on the EU (`api.eu.deepgram.com`), Australia (`api.au.deepgram.com`), or India (`api.in.deepgram.com`) [regional endpoints](/reference/regional-endpoints). Sending `keyterms` on another model returns an `Error` with code `KeytermsNotSupported`, and the stream continues with its previous settings.

The [`/v1/listen` API reference](/reference/speech-to-text/listen-streaming) now documents the `Configure` message.