Gemini 3.8 Flash TTS
google/gemini-3.8-flash-ttsGemini 3.8 Flash TTS by Google turns text into expressive speech with 30 prebuilt voices and natural-language style direction.
- Base price
- $0.04USD / run
- Execution
- async
- Model type
- audio
- Input fields
- 3
Try the model
Playground
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Examples
Select an example to load its inputs and result into the playground.
- Open result ↗
Input
{ "prompt": "Have a wonderful day!" }
Model card
Specifications
Pricing
- Base price
- $0.04 / run
Context & modalities
- Input
- Schema-defined
- Output
- audio
Capabilities
- Chat
- Not supported
- Vision
- Not supported
- Reasoning
- Not supported
- Structured output
- Not supported
- Function calling
- Not supported
- Audio input
- Not supported
Access
- Provider
- Model ID
- google/gemini-3.8-flash-tts
- Execution
- async
- Base URL
- https://api.sandbase.ai
- API
- Unified Run API
- Endpoint
- /v1/run
API README
Gemini 3.8 Flash TTS
Gemini 3.8 Flash TTS turns text into expressive speech with 30 prebuilt voices. Direct the delivery in plain language with style_instructions, such as tone, pace, or accent.
Fields
| Field | Type | Default | Notes |
|---|---|---|---|
prompt | string, required | — | Text to speak. |
style_instructions | string | — | How to say it, e.g. “warm and unhurried, slight smile”. |
voice | Achernar / Achird / Algenib / Algieba / Alnilam / Aoede / Autonoe / Callirrhoe / Charon / Despina / Enceladus / Erinome / Fenrir / Gacrux / Iapetus / Kore / Laomedeia / Leda / Orus / Pulcherrima / Puck / Rasalgethi / Sadachbia / Sadaltager / Schedar / Sulafat / Umbriel / Vindemiatrix / Zephyr / Zubenelgenubi | Kore | Prebuilt voice. |
Billing
$0.045 per started 1,000 characters of text, with a one-unit minimum.
| Text | Price |
|---|---|
| 200 characters | $0.045 |
| 1,000 characters | $0.045 |
| 2,500 characters | $0.135 |
Failed runs are not charged.
Prompting
- Put delivery direction in
style_instructions, not in the text itself.
Limits
- Single speaker per request.
Also on SandBase
Related: google/gemini-3.8-flash-lite-tts (cheaper), google/gemini-3.1-flash-tts (multi-speaker).
Start building
Send your first request
OpenAI-compatible endpoint with unified authentication and usage tracking.
# The quoted heredoc keeps Unicode and shell metacharacters unchanged.
result=$(curl --fail-with-body --silent \
-X POST "https://api.sandbase.ai/v1/run" \
-H "Authorization: Bearer $SANDBASE_API_KEY" \
-H "Content-Type: application/json" \
--data-binary @- <<'SANDBASE_JSON'
{
"model": "google/gemini-3.8-flash-tts",
"voice": "Kore",
"prompt": "Have a wonderful day!",
"style_instructions": "cheerful and friendly"
}
SANDBASE_JSON
)
run_id=$(printf '%s' "$result" | jq -r .id)
for attempt in $(seq 1 120); do
status=$(printf '%s' "$result" | jq -r .status)
case "$status" in completed|failed|timeout) break ;; esac
sleep 2
result=$(curl --fail-with-body --silent \
-H "Authorization: Bearer $SANDBASE_API_KEY" \
"https://api.sandbase.ai/v1/run/$run_id")
done
status=$(printf '%s' "$result" | jq -r .status)
[ "$status" = completed ] || { echo "Generation ended: $status" >&2; exit 1; }
printf '%s\n' "$result"Choose your model
Compare models
| Model | Type | Default price | Released |
|---|---|---|---|
Gemini 3.8 Flash TTSThis model Google | Audio | $0.04 / run | Sep 25, 2026 |
Google | Audio | $0.03 / run | Sep 25, 2026 |
Google | Audio | $0.10 / run | Sep 15, 2026 |
Google | Audio | $0.05 / run | Apr 16, 2026 |
Questions
FAQ
How do I call Google Gemini 3.8 Flash TTS through SandBase?
Create a SandBase API key, then send requests with the model ID "google/gemini-3.8-flash-tts" to Unified Run API (/v1/run) at https://api.sandbase.ai. The request examples on this page show the exact payload.
Do I need a separate Google account?
No. One SandBase API key and balance gives you access to Google Gemini 3.8 Flash TTS and the other models in the catalog; you do not need to sign up with Google separately.