---
name: "speech_synthesize"
area: "speech"
title: "Turn text into speech"
price: "$0.07 per 1,000 characters, rounded up, up to $0.35"
method: "POST"
url: "https://api.conecto.chat/v1/tools/speech_synthesize"
mcp_server: "https://api.conecto.chat/mcp/speech"
auth: "Authorization: Bearer <conecto_sk_ key>"
docs_url: "https://conecto.chat/tools/speech/speech_synthesize"
---

# Turn text into speech (`speech_synthesize`)

Reads text aloud in a stock voice and saves the MP3 in the file store with a download link; up to 5,000 characters a call.

An MP3 of the text read aloud by one of the voices (speech_list_voices), saved in the file store with a download link. Up to 5,000 characters a call; it reads the language the text is written in. The file carries a machine-readable mark that the speech is AI-generated (ID3: AIGenerated, IPTC digital source type).

Price: $0.07 per 1,000 characters, rounded up, up to $0.35. A call that fails costs nothing.

## Use it when

The business needs spoken audio: a phone greeting, a voice note, a short audio guide.

## Say this to your agent

> Record a short holiday greeting for the phone line: we're closed from December 24 to 26.

## Inputs

| Name | Type | Required | Description | Allowed values | Default |
|---|---|---|---|---|---|
| `text` | string | yes | 1 to 5,000 characters. |  |  |
| `voice` | string | no | A voice from speech_list_voices; the first one when left out. Up to 40 characters. |  |  |
| `name` | string | no | File name for the MP3. Up to 200 characters. |  |  |

## Example

Written for Halverson Cycle & Repair, a bike shop with a repair workshop in Portland, Oregon.

MCP: call `speech_synthesize` on the MCP server `https://api.conecto.chat/mcp/speech` with these arguments:

```json
{
  "text": "Thank you for calling Halverson Cycle & Repair. The shop and the workshop are closed from December 24 to 26. From December 27 we are here again, Monday to Saturday, 10 to 7.",
  "voice": "sarah",
  "name": "Holiday greeting 2026"
}
```

REST:

```bash
curl https://api.conecto.chat/v1/tools/speech_synthesize \
  -H "Authorization: Bearer $CONECTO_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text": "Thank you for calling Halverson Cycle & Repair. The shop and the workshop are closed from December 24 to 26. From December 27 we are here again, Monday to Saturday, 10 to 7.", "voice": "sarah", "name": "Holiday greeting 2026"}'
```

## Response

```json
{
  "call_id": "5f0c8a2e-3b7d-4c1e-9a64-2d8e1f7b0c93",
  "tool": "speech_synthesize",
  "status": "succeeded",
  "replayed": false,
  "cost_usd": "$0.07",
  "balance_usd": "$19.75",
  "result": {
    "file": {
      "file_id": "c051fcb9-6532-4f08-870e-7245fe5a40b2",
      "name": "Holiday greeting 2026.mp3",
      "content_type": "audio/mpeg",
      "size": "22 bytes",
      "size_bytes": 22,
      "sha256": "3123154ba6b9b87fafaa24ff345f6d9d142e29aefb0133eaf2b93b77b3a06e78",
      "created_at": "2026-10-14T08:00:00+00:00",
      "download_url": "https://cncto.co/d/c051fcb9-6532-4f08-870e-7245fe5a40b2?t=eyJmIjoiYzA1MWZjYjktNjUzMi00ZjA4LTg3MGUtNzI0NWZlNWE0MGIyIiwiZXhwIjoxNzkyMTYwNDgzfQ:1xHMKh:jr4svVUu7Ktd-JQ4PLFfb0imf1TNqkGlqdeTaicPuiU",
      "link_expires_in_hours": 24
    },
    "voice": "sarah",
    "characters": 173
  }
}
```

`result`: file: the MP3 with its file_id, size and download link; voice; characters: how many were read.

## Errors

| Code | Status | When | Fix |
|---|---|---|---|
| `not_found` | 404 | No stock voice has that name. | Pick one from speech_list_voices. |
| `storage_full` | 409 | The file store has no room for the MP3. | Delete files with files_delete, or add room with files_add_storage. |
| `unavailable` | 503 | Speech is not switched on yet, or the speech service failed or did not answer. | Try again later; nothing was charged. |

The refusals every tool can give (401 key, 402 balance, 429 limits) are on the errors page: https://conecto.chat/docs/errors.md

## Related

- [speech_transcribe](https://conecto.chat/tools/speech/speech_transcribe.md): Turns the speech in an audio or video file from the store into text, in about 100 languages, with speakers and timestamps if asked. $0.01 per started minute of audio.
- [speech_list_voices](https://conecto.chat/tools/speech/speech_list_voices.md): The stock voices text can be read aloud in; each speaks about 30 languages, and the text decides which. Free up to 1,000,000 reads a month.