Gemini 3.8 Flash TTS API reference

Call Gemini 3.8 Flash TTS from your own code with one PopNow API key. Below are the exact model IDs to send, every input field the model accepts, what each request costs in credits, and a request you can paste into a terminal.

At a glance

Made by: Google
Output: Audio
From: 0.05 credits per second of output ($0.0005)
Typical time: about 11 s
Model IDs: google/gemini-3.8-flash-tts/text-to-speech

1 credit = $0.01. A task holds the highest possible charge when it is accepted and settles the real amount when it finishes, rounded up to whole credits; failed tasks are not charged. Ask POST /api/v1/jobs/quote for the exact figure before you run.

Text to Speech

google/gemini-3.8-flash-tts/text-to-speech

Price

Option	Credits (per second of output)	US dollars
`Default`	0.05	$0.0005

Parameters

Field	Type	Default	Allowed	What it does
`text`Optional	`string`	—	up to 5,000 characters	The words to be spoken, exactly as written. Direction such as [whispering] or [sighs] goes into the text itself.
`dialogue`Optional	`array<object>`	—	up to 20 items	A scripted conversation, used instead of text: each line names a speaker from speakers.
`speakers`Optional	`array<object>`	—	up to 2 items	The cast for dialogue: one or two voices, each with a name the lines refer to.
`voice_id`Optional	`string`	`Kore`	Achernar, Achird, Algenib, Algieba, Alnilam, Aoede, Autonoe, Callirrhoe, Charon, Despina, Enceladus, Erinome, Fenrir, Gacrux, … (+16)	Prebuilt voice that reads the text. Each voice has a fixed character.
`style`Optional	`string`	—	whisper, empathetic, vocal_smile, newscaster, promo_hype, deadpan	Overall manner of the reading. Omit it to use the voice's own default manner.
`pace`Optional	`string`	—	natural, rapid_fire, the_drift, staccato	Rhythm of the reading. Omit it to keep the voice's own rhythm.
`accent`Optional	`string`	—	neutral, american_general, american_valley, american_south, british_rp, british_brixton, transatlantic, australian	English accent used for the reading.
`instructions`Optional	`string`	—	up to 1,000 characters	How to read the text: mood, distance from the microphone, who is listening. Shapes the delivery and is not spoken.
`scene`Optional	`string`	—	up to 500 characters	Where and to whom the words are spoken. Shapes the delivery and is not spoken.
`temperature`Optional	`number`	—	0 to 2	Variation between takes; higher is less predictable.

Example request

This request runs as it is; any field you leave out uses its default. Put your key in POPNOW_API_KEY first.

POST /api/v1/jobs/createTask?wait=60

curl -X POST "https://api.popnow.ai/api/v1/jobs/createTask?wait=60" \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{
  "model": "google/gemini-3.8-flash-tts/text-to-speech",
  "input": {
    "text": "Hi there! This voice was created with the PopNow API in just a few seconds."
  }
}'

The response carries a taskId straight away. Read the result with GET /api/v1/jobs/recordInfo, or add callBackUrl to be notified.

GET /api/v1/jobs/recordInfo

curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=TASK_ID_FROM_CREATE_TASK" \
  -H "Authorization: Bearer $POPNOW_API_KEY"