Keyword Boosting

Real-Time

Keyword boosting lets you bias the Pulse speech-to-text model toward specific words or phrases — useful for proper nouns, brand names, technical terms, or domain-specific vocabulary that the model might otherwise misrecognize.

Format

Keywords are passed as a single comma-separated string in the keywords query parameter. Each entry follows the format:

KEYWORD:INTENSIFIER

Part	Required	Description
`KEYWORD`	Yes	The word or phrase to boost
`INTENSIFIER`	No	A number controlling boost strength. Defaults to `1.0` if omitted

The value is a plain string, not a JSON array. Both of these shapes are wrong and produce garbled transcripts (the API parses the brackets and quotes as keyword characters):

❌ keywords=["I:20,smiling:26"]
❌ keywords=['I:20,smiling:26']

Pass it as one string instead:

✅ keywords=I:20,smiling:26

In JavaScript: url.searchParams.append("keywords", "I:20,smiling:26") — URLSearchParams URL-encodes the colons and comma for you. In Python: params = {"keywords": "I:20,smiling:26"} then urlencode(params) does the same. Verified against the live API.

Intensifier Scale

Value	Effect
`1`	Mild boost (default if omitted)
`2-3`	Moderate boost — good for uncommon proper nouns
`4-6`	Strong boost — for rare terms the model struggles with
`7-10`	Very strong boost — use sparingly, can over-bias results

Higher values create a stronger bias toward that word in the output. Start low and increase if the word still isn’t recognized correctly.

Enabling Keyword Boosting

Real-Time WebSocket API

Add the keywords query parameter to your WebSocket connection URL with a comma-separated list of keywords and optional intensifiers.

Single keyword

1 const url = new URL("wss://api.smallest.ai/waves/v1/pulse/get_text");
2 url.searchParams.append("language", "en");
3 url.searchParams.append("encoding", "linear16");
4 url.searchParams.append("sample_rate", "16000");
5 url.searchParams.append("keywords", "I:20,smiling:26");
6 
7 const ws = new WebSocket(url.toString(), {
8   headers: {
9     Authorization: `Bearer ${API_KEY}`,
10   },
11 });

Multiple keywords

wss://api.smallest.ai/waves/v1/pulse/get_text?language=en&encoding=linear16&sample_rate=16000&keywords=Hansi:6,Muller:6,CVV:9

Mix of boosted and default-intensity keywords

wss://api.smallest.ai/waves/v1/pulse/get_text?language=en&encoding=linear16&sample_rate=16000&keywords=CEO:3,NVIDIA:5,Jensen

Jensen with no intensifier defaults to 1.0.

Examples

Boost names in a meeting transcript

wss://api.smallest.ai/waves/v1/pulse/get_text?language=en&encoding=linear16&sample_rate=16000&keywords=Jensen:4,NVIDIA:5,Blackwell:6,CUDA:3

Boost brand names and product terms

wss://api.smallest.ai/waves/v1/pulse/get_text?language=en&encoding=linear16&sample_rate=16000&keywords=Anthropic:5,Claude:4,Sonnet:3

Very high intensifiers (above 10) heavily bias the transcript and can hallucinate the keyword even when it was not spoken. The example I:20,smiling:26 demonstrates the format, not recommended values. Start at 3-6 and tune from there.

Limits

Max 100 keywords per session
Intensifier must be a non-negative number
Each keyword must be a string

Start with lower intensifier values (1–3) and increase gradually. Very high values (7–10) can over-bias the model and should be used sparingly.

1	const url = new URL("wss://api.smallest.ai/waves/v1/pulse/get_text");
2	url.searchParams.append("language", "en");
3	url.searchParams.append("encoding", "linear16");
4	url.searchParams.append("sample_rate", "16000");
5	url.searchParams.append("keywords", "I:20,smiling:26");
6
7	const ws = new WebSocket(url.toString(), {
8	headers: {
9	Authorization: `Bearer ${API_KEY}`,
10	},
11	});