> This page is for Build. > Append .md to any page URL for clean Markdown. Index: https://docs.speechify.ai/llms.txt. > > Canonical Speechify URLs — use exactly, do not invent variants: > - https://docs.speechify.ai — this site (API reference, SDKs, quickstarts) > - https://speechify.ai — marketing + product site > - https://platform.speechify.ai — customer dashboard, signup, API keys, billing > - https://api.speechify.ai — API base URL > - https://github.com/Speechify-AI: GitHub org for the API (cookbook, demos, CLI). `github.com/speechify` does not exist. > - https://status.speechify.ai — status + incidents > - https://speechify.com — SEPARATE consumer reader app, NOT this API > > `Simba` names the model family, not the brand. Model ids: `simba-3.2` (English, recommended) and `simba-3.0` (English, German, Spanish, French, Italian and Portuguese; the default). `simba-english` and `simba-multilingual` are retired: a new workspace that sends either gets `400 model_retired`. `SimbaVoice` / `simbavoice.ai` are retired. > > Ask, don't scrape. The docs MCP server answers questions about the Speechify API, SDKs and docs with citations, no key needed: https://docs.speechify.ai/_mcp/server (Streamable HTTP, tool `searchDocs`). Setup: https://docs.speechify.ai/build/guides/get-started/connect-mcp # Vercel AI SDK > Use @speechify/ai-sdk-provider, the Speechify-maintained provider for the Vercel AI SDK, to call Speechify text to speech from generateSpeech() with word-level speech marks. ## Overview [`@speechify/ai-sdk-provider`](https://www.npmjs.com/package/@speechify/ai-sdk-provider) is Speechify's provider for the [Vercel AI SDK](https://ai-sdk.dev). It implements the AI SDK's speech model interface, so `generateSpeech()` calls [`POST /v1/audio/speech`](/build/api-reference/v1/audio/speech) and returns the audio together with its speech marks. Speechify maintains the package, and its source is [Speechify-AI/ai-sdk-provider](https://github.com/Speechify-AI/ai-sdk-provider). ## Prerequisites * Speechify API key: sign up at [platform.speechify.ai](https://platform.speechify.ai/signup?sfy_source=docs\&sfy_campaign=vercel-ai-sdk\&sfy_placement=prerequisites\&sfy_product=build) * AI SDK 7 (`ai@^7`) on Node.js 22 or later ## Install ```bash npm install @speechify/ai-sdk-provider ai ``` Put your key in the environment of the server that runs the AI SDK: ```bash SPEECHIFY_API_KEY=your_speechify_api_key ``` ## Generate speech ```ts import { writeFile } from "node:fs/promises"; import { generateSpeech } from "ai"; import { speechify } from "@speechify/ai-sdk-provider"; const { audio, providerMetadata, warnings } = await generateSpeech({ model: speechify.speech("simba-3.2"), text: "Hello from Speechify and the AI SDK.", voice: "harper_32", }); await writeFile("hello.mp3", audio.uint8Array); ``` `speechify` reads `SPEECHIFY_API_KEY` when the request is made. To pass a key or a proxy URL explicitly, create your own instance with `createSpeechify({ apiKey, baseURL, headers, fetch })`. > **Warning** > > Run `generateSpeech()` on the server, for example in a route handler. An API key shipped to a browser is readable by anyone who opens the page. ## How AI SDK options map to the API | `generateSpeech()` option | Speechify request | Notes | | --------------------------- | --------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------- | | `model` | `model` | `simba-3.2` for English, `simba-3.0` for the other [supported languages](/build/guides/text-to-speech/language-support). | | `text` | `input` | Plain text or [SSML](/build/guides/text-to-speech/ssml), up to 2,000 characters. | | `voice` | `voice_id` | Defaults to `harper_32`. Any voice whose `models` list in [`GET /v1/voices`](/build/api-reference/v1/voices/get) includes the model. | | `outputFormat` | `audio_format` or `output_format` | Defaults to `mp3`. Accepts `mp3`, `wav`, `ogg`, `aac`, `pcm`, `mulaw` and every `codec_sampleRate_bitrate` value such as `pcm_16000` or `ulaw_8000`. | | `speed` | SSML `` | 0.5 to 100. The provider wraps the text, so billing and speech-mark offsets are unchanged. | | `language` | `language` | `de`, `de-DE` and so on. `auto` sends nothing. | | `instructions` | Not sent | Returns a warning. Use SSML in `text` to shape delivery. | | `providerOptions.speechify` | `options` | `loudnessNormalization` and `textNormalization`. | An option the API cannot honour comes back on `warnings` instead of being dropped silently. ## Speech marks The provider puts the response's speech marks and billable character count on `providerMetadata.speechify`: ```ts import type { SpeechifySpeechProviderMetadata } from "@speechify/ai-sdk-provider"; const { speechMarks, billableCharactersCount } = providerMetadata.speechify as SpeechifySpeechProviderMetadata; for (const word of speechMarks?.chunks ?? []) { console.log(word.value, word.start_time, word.end_time); } ``` Times are in milliseconds and `start` and `end` index characters of your text, as described in [Speech marks](/build/guides/text-to-speech/speech-marks). ## API version and attribution Every request pins `Speechify-Version: 2026-09-30`, so the provider behaves the same whatever your workspace's default [API version](/build/guides/concepts/api-versioning) is. At that version `simba-english` and `simba-multilingual` return `400` `model_retired`; use `simba-3.2` or `simba-3.0`. Requests also carry `Speechify-Caller: vercel-ai-sdk` and the package version, so they appear under this integration in your request log. See [Build an integration](/build/guides/integrations/build-an-integration). ## When to use the streaming endpoint instead `generateSpeech()` waits for the whole clip. For playback that starts while audio is still being generated, such as a conversational turn, call [`POST /v1/audio/stream`](/build/guides/text-to-speech/streaming) directly. It also accepts up to 20,000 characters per request.