# Generate speech (OpenAI) - Workflow node | Docs - nodulz

Source: https://nodulz.com/docs/nodes/generate_speech_openai

Language: en

Turn text into speech using an OpenAI credential.

## Usage and specifics

Select an OpenAI credential and a model suitable for transcription or speech synthesis. Supply the required audio or text and preserve output format and MIME type.

Technical type : `generate_speech_openai`. Runtime : `nodulz`.

## Credentials and prerequisites

- [Create and configure the credential : openai](/docs/credentials/openai)

Create credentials in your nodulz instance’s Credentials area, then select them on the node. Availability depends on ownership and sharing. See the [credentials guide](/docs/credentials) for access and rotation.

## Parameters

Names below are technical keys. Defaults are not a ready-to-run configuration: complete fields required by your operation. Paths containing [] describe list items; some fields depend on the selected mode.

| Parameter | Type | Default | Values / limits |
| --- | --- | --- | --- |
| `credentialId` | `string` | `""` | - |
| `timeoutSeconds` | `number` | `120` | -; ≥ 1, ≤ 3600 |
| `text` | `string` | `""` | - |
| `model` | `string` | `"gpt-4o-mini-tts"` | -; min 1 |
| `voice` | `enum` | `"coral"` | `alloy`, `ash`, `ballad`, `coral`, `echo`, `fable`, `nova`, `onyx`, `sage`, `shimmer`, `verse`, `marin`, `cedar` |
| `format` | `enum` | `"mp3"` | `mp3`, `wav`, `flac` |
| `speed` | `number` | `1` | -; ≥ 0.25, ≤ 4 |
| `instructions` | `string` | `""` | - |

## Configuration help

| Setting | Purpose and guidance |
| --- | --- |
| `credentialId`<br>AI credential | OpenAI API credential accessible to the workflow owner. The provider bills API requests. |
| `model`<br>Model | Transcription: choose whisper-1 for Whisper, gpt-4o-mini-transcribe (default), or gpt-4o-transcribe. You can also enter another model ID. Speech: gpt-4o-mini-tts by default. |

## Initial configuration

Initial catalog configuration example, to adapt before running. Keep secrets in credentials.

```json
{
  "credentialId": "",
  "timeoutSeconds": 120,
  "text": "",
  "model": "gpt-4o-mini-tts",
  "voice": "coral",
  "format": "mp3",
  "speed": 1,
  "instructions": ""
}
```

## Verification

Test with representative data. Check node output in the inspector and logs, then use editor mapping for downstream fields. A trigger test with a simulated payload does not validate external service delivery.

See also : [Expressions and data](/docs/expressions), [Executions](/docs/executions), [Node catalog](/docs/nodes).

## Explore further

- [Features - nodulz](https://nodulz.com/product/overview)
- [Node catalog - nodulz](https://nodulz.com/product/catalog)
- [MCP server - nodulz](https://nodulz.com/product/mcp)
- [Pricing - nodulz](https://nodulz.com/pricing)
- [Use cases and workflow automation - nodulz](https://nodulz.com/use-cases)
- [Choose what your workflows can do. - nodulz](https://nodulz.com/compare)
- [Documentation - nodulz](https://nodulz.com/docs)