Gemini 3.8 Flash-Lite TTS Serverless API

Expressive multilingual text-to-speech with two-speaker dialogue.

PlaygroundAPI
Pricing
~8.75s
POST /v2/gemini-3.8-flash-lite-tts · submit + poll
 1# pip install "segmind>=1.1.0"
 2# export SEGMIND_API_KEY="YOUR_API_KEY"
 3import segmind
 4
 5# Async (v2): submit to the queue and block until COMPLETED.
 6# run() returns the final result dict (600s deadline, 1.0s poll by default).
 7result = segmind.run(
 8    "gemini-3.8-flash-lite-tts",
 9    text="Here we go — the final hundred of the women's 400. <short pause> Delgado's in lane four, half a stride back... can she find another gear? And she does! <gasp> She's flying now — 3, 2, meters to go — Delgado takes it! A new national record — 49.06! The Halden Arena is on its feet.",
10    voice_1="Puck",
11    style="live athletics commentary: start tense and measured, then build to an explosive, shouting climax at the finish",
12    temperature=1.1,
13)
14print(result["status"])                      # COMPLETED
15print(result.get("output"))                  # model output (e.g. media URL)
16print(result["metrics"]["inference_time"])   # server compute seconds
17
18# --- Or submit + poll manually (track request_id, control the cadence) ---
19from segmind import SegmindClient, InferenceFailed, InferenceTimeout
20
21client = SegmindClient()                      # reads SEGMIND_API_KEY
22payload = {
23    "text": "Here we go — the final hundred of the women's 400. <short pause> Delgado's in lane four, half a stride back... can she find another gear? And she does! <gasp> She's flying now — 3, 2, meters to go — Delgado takes it! A new national record — 49.06! The Halden Arena is on its feet.",
24    "voice_1": "Puck",
25    "style": "live athletics commentary: start tense and measured, then build to an explosive, shouting climax at the finish",
26    "temperature": 1.1,
27}
28job = client.submit_async("gemini-3.8-flash-lite-tts", **payload)
29print(job.request_id)                         # available immediately
30try:
31    result = job.wait(timeout=600, interval=1.0)
32except InferenceTimeout as e:
33    print("still running:", e.request_id)
34except InferenceFailed as e:
35    print("failed:", e.detail)

API Endpoint

POSThttps://api.segmind.com/v1/gemini-3.8-flash-lite-tts

Parameters

textrequired
string

Script to speak, with inline cues like <laughs>, <sigh>, <short pause>; name-prefix each line for two speakers. Write non-English scripts in the target language.

Default: "Here we go — the final hundred of the women's 400. <short pause> Delgado's in lane four, half a stride back... can she find another gear? And she does! <gasp> She's flying now — 3, 2, meters to go — Delgado takes it! A new national record — 49.06! The Halden Arena is on its feet."
styleoptional
string

Plain-English delivery direction applied to every line, e.g. 'whispered urgently'. Use as the main expressiveness control; pair with temperature.

temperatureoptional
number

Expressiveness from 0 to 2. Use 0.2-0.5 for steady narration, 0.8-1.4 for emotional or dramatic delivery.

Default: 0.4Range: 0 - 2
voice_1optional
string

Primary speaker voice, one of 30 named options. Try Puck or Fenrir for energetic reads, Enceladus for calm or whispered delivery.

Default: "Kore"
Allowed values (30 total):
"Kore""Puck""Charon""Zephyr""Fenrir""Leda""Orus""Aoede""Callirrhoe""Autonoe"+20 more
voice_2optional
string

Optional second speaker for two-person dialogue; leave empty for one voice. When set, prefix each of their lines with this voice name.

Allowed values (30 total):
"Kore""Puck""Charon""Zephyr""Fenrir""Leda""Orus""Aoede""Callirrhoe""Autonoe"+20 more

Response Type

Returns: Audio

Asynchronous requests (v2)

Use Async for video, long-running (>~60s), or high-concurrency workloads; Sync is simplest for fast image & LLM calls. Async submits a request and you poll it to completion.

  1. 1
    POST /v2/gemini-3.8-flash-lite-tts

    Submit — returns request_id, status_url, response_url

  2. 2
    GET /v2/requests/{id}/status

    Poll — until COMPLETED or FAILED

  3. 3
    GET /v2/requests/{id}

    Result — final response body

Status states

QUEUED— Accepted, waiting for a worker
PROCESSING— Running on a worker
COMPLETED— Done — result body is ready
FAILED— Errored (incl. content/RAI blocks)
  • A FAILED request is served as HTTP 422 — the body still carries the error detail.
  • An unknown or expired request_id returns HTTP 404.
  • Results are retained for 1 hour, then expire.
  • Content / RAI blocks surface as FAILED, not a separate state.
  • Track completion by polling the status endpoint.

Common Error Codes

The API returns standard HTTP status codes. Detailed error messages are provided in the response body.

400

Bad Request

Invalid parameters or request format

401

Unauthorized

Missing or invalid API key

403

Forbidden

Insufficient permissions

404

Not Found

Model or endpoint not found

406

Insufficient Credits

Not enough credits to process request

429

Rate Limited

Too many requests

500

Server Error

Internal server error

502

Bad Gateway

Service temporarily unavailable

504

Timeout

Request timed out