Inworld 1.5 Mini Text To Speech
Playground
Try it on WavespeedAI!Inworld 1.5 Mini delivers high-quality text-to-speech synthesis with 56+ multilingual voices, adjustable speaking rate, and natural-sounding audio output. Ready-to-use REST inference API, best performance, no coldstarts, affordable pricing.
Features
Inworld 1.5 Mini Text-to-Speech
Inworld 1.5 Mini is a lightweight, ultra-affordable text-to-speech model that converts written text into natural speech. It offers the same voice selection, speaking rate, and expressiveness controls as the Max model — at half the cost. Perfect for high-volume workflows, prototyping, and budget-conscious production.
- Need higher quality? Try Inworld 1.5 Max Text-to-Speech
Why Choose This?
-
Ultra-low cost Just $0.005 per 1,000 characters — the most affordable option for text-to-speech at scale.
-
Voice selection Choose from a library of distinct voice identities to match your brand, character, or use case.
-
Speaking rate control Adjust the speed of speech to suit narration, dialogue, announcements, or any delivery style.
-
Temperature control Fine-tune expressiveness — lower values for consistent delivery; higher values for more dynamic, varied speech.
-
Fast processing Lightweight architecture delivers quick turnaround, ideal for real-time or high-volume pipelines.
Parameters
| Parameter | Required | Description |
|---|---|---|
| text | Yes | The text content to convert to speech |
| voice_id | No | Voice preset to use (e.g., Hades) |
| speaking_rate | No | Speed of speech (default: 1) |
| temperature | No | Expressiveness level (default: 1) |
How to Use
- Enter your text — type or paste the content you want converted to speech.
- Select a voice — choose a voice preset from the voice_id dropdown.
- Adjust speaking rate — slide to control how fast or slow the speech is delivered.
- Adjust temperature — slide to control the expressiveness and variation in delivery.
- Run — submit and download the generated audio.
Pricing
| Characters | Cost |
|---|---|
| Up to 1,000 | $0.005 |
| Up to 2,000 | $0.010 |
| Up to 5,000 | $0.025 |
| Up to 10,000 | $0.050 |
Billing Rules
- Rate: $0.005 per 1,000 characters
- Rounding: character count is rounded up to the next 1,000
Best Use Cases
- High-Volume Production — Generate large batches of audio at minimal cost.
- Prototyping & Testing — Quickly preview voiceovers before committing to final production.
- Chatbots & Virtual Assistants — Add voice output to conversational AI at scale.
- Content Accessibility — Convert written content to audio affordably for wider audiences.
- Game & App Dialogue — Generate character voice lines for interactive experiences on a budget.
Pro Tips
- Use Mini for drafting and iteration, then switch to Max for final production if higher quality is needed.
- Keep speaking_rate around 1 for natural pacing; adjust lower for dramatic reads, higher for quick announcements.
- Lower temperature gives more predictable, consistent output — great for automated systems.
- Break long texts into logical paragraphs for better pacing and natural pauses.
Notes
- Text is the only required field.
- Billing is based on character count, rounded up to the nearest 1,000.
- For maximum voice quality, consider Inworld 1.5 Max.
Authentication
For authentication details, please refer to the Authentication Guide.
API Endpoints
Submit Task & Query Result
# Submit the task
curl --location --request POST "https://api.wavespeed.ai/api/v3/inworld/1.5-mini/text-to-speech" \
--header "Content-Type: application/json" \
--header "Authorization: Bearer ${WAVESPEED_API_KEY}" \
--data-raw '{
"voice_id": "Alex",
"speaking_rate": 1,
"temperature": 1
}'
# Get the result
curl --location --request GET "https://api.wavespeed.ai/api/v3/predictions/${requestId}/result" \
--header "Authorization: Bearer ${WAVESPEED_API_KEY}"
Parameters
Task Submission Parameters
Request Parameters
| Parameter | Type | Required | Default | Range | Description |
|---|---|---|---|---|---|
| text | string | Yes | - | - | Styling instructions on how to synthesize the content in the text field. |
| voice_id | string | No | Alex | Alex, Ashley, Craig, Deborah, Dennis, Edward, Elizabeth, Hades, Julia, Pixie, Mark, Olivia, Priya, Ronald, Sarah, Shaun, Theodore, Timothy, Wendy, Dominus, Hana, Clive, Carter, Blake, Luna, Yichen, Xiaoyin, Xinyi, Jing, Erik, Katrien, Lennart, Lore, Alain, Hélène, Mathieu, Étienne, Johanna, Josef, Gianni, Orietta, Asuka, Satoshi, Hyunwoo, Minji, Seojun, Yoona, Szymon, Wojciech, Heitor, Maitê, Diego, Lupita, Miguel, Rafael, Svetlana, Elena, Dmitry, Nikolai, Riya, Manoj, Yael, Oren, Nour, Omar | The voice to use for speech generation. |
| speaking_rate | number | No | 1 | 0.5 ~ 1.5 | The speed of speaking. |
| temperature | number | No | 1 | 0.7 ~ 1.5 | The temperature to use for the generation. A higher value means more randomness in the output. |
Response Parameters
| Parameter | Type | Description |
|---|---|---|
| code | integer | HTTP status code (e.g., 200 for success) |
| message | string | Status message (e.g., “success”) |
| data.id | string | Unique identifier for the prediction, Task Id |
| data.model | string | Model ID used for the prediction |
| data.outputs | array | Array of URLs to the generated content (empty when status is not completed) |
| data.urls | object | Object containing related API endpoints |
| data.urls.get | string | URL to retrieve the prediction result |
| data.has_nsfw_contents | array | Array of boolean values indicating NSFW detection for each output |
| data.status | string | Status of the task: created, processing, completed, or failed |
| data.created_at | string | ISO timestamp of when the request was created (e.g., “2023-04-01T12:34:56.789Z”) |
| data.error | string | Error message (empty if no error occurred) |
| data.timings | object | Object containing timing details |
| data.timings.inference | integer | Inference time in milliseconds |
Result Request Parameters
| Parameter | Type | Required | Default | Description |
|---|---|---|---|---|
| id | string | Yes | - | Task ID |
Result Response Parameters
| Parameter | Type | Description |
|---|---|---|
| code | integer | HTTP status code (e.g., 200 for success) |
| message | string | Status message (e.g., “success”) |
| data | object | The prediction data object containing all details |
| data.id | string | Unique identifier for the prediction, the ID of the prediction to get |
| data.model | string | Model ID used for the prediction |
| data.outputs | string | Array of URLs to the generated content (empty when status is not completed). |
| data.urls | object | Object containing related API endpoints |
| data.urls.get | string | URL to retrieve the prediction result |
| data.status | string | Status of the task: created, processing, completed, or failed |
| data.created_at | string | ISO timestamp of when the request was created (e.g., “2023-04-01T12:34:56.789Z”) |
| data.error | string | Error message (empty if no error occurred) |
| data.timings | object | Object containing timing details |
| data.timings.inference | integer | Inference time in milliseconds |