# Text to speech

URL: https://clippie.ai/developers/docs/text-to-speech

Turns text into an mp3 narration with a Clippie voice or one of your cloned voices, with word timings. Spends voiceover minutes for the audio's length (about 150 words a minute), and the same in caption minutes for the word timings. Finishes within the call: the job comes back completed with audioUrl and captions.words.

## At a glance

| Property | Value |
| --- | --- |
| REST | `POST https://api.clippie.ai/v1/ai/speech` |
| MCP tool | `text_to_speech` |
| Scope | `create` |
| Cost | Spends credits or minutes, at the same prices as the app. Send `"dryRun": true` (or call [estimate_cost](https://clippie.ai/developers/docs/estimate-cost.md)) first to see the exact cost without spending anything. |
| Limit bucket | `voiceover` (see [Rate limits](https://clippie.ai/developers/docs.md#rate-limits)) |

## Parameters

| Name | In | Type | Required | Default | Description |
| --- | --- | --- | --- | --- | --- |
| `text` | body | string | Yes |  | What to say. 1-5000 chars. |
| `voiceId` | body | string | Yes |  | A voice id from list_voices (Clippie's or your own). 1-64 chars. |
| `stability` | body | number | No | `0.5` | 0.01-1. |
| `similarity` | body | number | No | `0.75` | 0.01-1. |
| `language` | body | string | No |  | Language code, e.g. "en". Up to 10 chars. |
| `wordTimestamps` | body | boolean | No | `true` | Also return word timings (transcribes the audio, which uses caption minutes too). |
| `dryRun` | body | boolean | No |  | Check the request and return { estimate } (credits and minutes) without spending anything. |
| `webhookUrl` | body | string (URL) | No |  | https URL that receives job.completed / job.failed, signed with your webhook secret. Up to 2048 chars. |
| `Idempotency-Key` | header | string | No |  | Retry-safe key: a retry with the same key and body within 24 hours returns the first job instead of starting (and charging) again. The same key with a different body is a 409. MCP clients pass it as the idempotencyKey argument. 1-255 chars. MCP: `idempotencyKey`. |

## Example

curl:

```bash
# 1. Dry run: the exact cost, nothing is spent.
curl https://api.clippie.ai/v1/ai/speech \
  -H "Authorization: Bearer $CLIPPIE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "Clippie turns your ideas into finished videos.",
    "voiceId": "VOICE_ID",
    "dryRun": true
  }'
# => { "dryRun": true, "estimate": { "credits": ..., "minutes": { ... }, "wouldSucceed": true } }

# 2. The real call. Keep the key and send the same one if you retry, so it is never charged twice.
KEY=$(uuidgen)
curl https://api.clippie.ai/v1/ai/speech \
  -H "Authorization: Bearer $CLIPPIE_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $KEY" \
  -d '{
    "text": "Clippie turns your ideas into finished videos.",
    "voiceId": "VOICE_ID"
  }'
# => 202 { "job": { "id": "job_...", "status": "queued", ... } }
```

text-to-speech.mjs:

```js
import { randomUUID } from 'node:crypto';

const auth = { Authorization: `Bearer ${process.env.CLIPPIE_API_KEY}` };

const input = {
  "text": "Clippie turns your ideas into finished videos.",
  "voiceId": "VOICE_ID"
};

async function call(body, headers = {}) {
  const res = await fetch('https://api.clippie.ai/v1/ai/speech', {
    method: 'POST',
    headers: { ...auth, 'Content-Type': 'application/json', ...headers },
    body: JSON.stringify(body),
  });
  const json = await res.json();
  if (!res.ok) throw new Error(`${json.error.type}: ${json.error.message}`);
  return json;
}

// 1. Dry run: the exact cost, nothing is spent. Confirm it before going on.
const { estimate } = await call({ ...input, dryRun: true });
console.log(estimate); // { credits, minutes, wouldSucceed, reason }

// 2. Create. Keep the key and reuse it on retries, so a retry never charges twice.
let { job } = await call(input, { 'Idempotency-Key': randomUUID() });

// 3. Wait. Each call holds for up to 30 seconds until the job changes.
while (!['completed', 'failed', 'canceled'].includes(job.status)) {
  const res = await fetch(`https://api.clippie.ai/v1/jobs/${job.id}?wait=30`, { headers: auth });
  ({ job } = await res.json());
}
console.log(job.status, job.output);
```

## Response

`202 { job }`: the job, straight away. Wait for it with [Get job](https://clippie.ai/developers/docs/get-job.md) (`?wait=30`) or a `webhookUrl`; see [Jobs and waiting](https://clippie.ai/developers/docs.md#jobs). With `"dryRun": true` the answer is `200 { dryRun: true, estimate }` and nothing is started.

202 Accepted:

```json
{
  "job": {
    "id": "job_abc123",
    "object": "job",
    "kind": "text_to_speech",
    "status": "queued",
    "step": null,
    "progress": null,
    "input": {
      "prompt": "The lost library of Alexandria"
    },
    "output": null,
    "cost": {
      "credits": 0,
      "minutes": {
        "voiceover": 1,
        "captions": 1,
        "export": 1
      }
    },
    "error": null,
    "source": "api",
    "webhookUrl": null,
    "createdAt": "2026-10-24T12:00:00.000Z",
    "startedAt": null,
    "completedAt": null
  }
}
```

Dry run (200), shape only:

```json
{
  "dryRun": true,
  "estimate": {
    "credits": 0,
    "minutes": {
      "voiceover": 0,
      "captions": 0,
      "export": 0
    },
    "wouldSucceed": true
  }
}
```

## From an MCP client

Your AI calls `text_to_speech` with the same fields as JSON arguments, plus `idempotencyKey` instead of the header. See [MCP server](https://clippie.ai/developers/docs.md#mcp) to connect one.

tools/call:

```json
{
  "name": "text_to_speech",
  "arguments": {
    "text": "Clippie turns your ideas into finished videos.",
    "voiceId": "VOICE_ID",
    "idempotencyKey": "a-unique-key-per-thing-you-make"
  }
}
```