> 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

# Concepts

## Docs

- [API Versioning](https://docs.speechify.ai/build/guides/concepts/api-versioning.md): How Speechify API date-based versioning works, including the Speechify-Version header, workspace defaults, and deprecation windows.
- [Models](https://docs.speechify.ai/build/guides/concepts/models.md): Compare Speechify's streaming-native TTS models. Simba 3.2 is recommended for English; Simba 3.0 is the API default with six languages across seven locales. Both support voice cloning on paid plans.
- [Audio formats](https://docs.speechify.ai/build/guides/concepts/audio-formats.md): The two parameters that decide what bytes come back, and which one wins.
- [API Limits](https://docs.speechify.ai/build/guides/concepts/api-limits.md): Speechify API rate limits and concurrency limits by plan (Free through Enterprise), plus per-endpoint character limits. Every /v1/audio synthesis endpoint shares one per-account rate and concurrency budget. Includes 429 Too Many Requests handling with Retry-After, rate_limited, and concurrency_limit_reached.
- [Spend Limits](https://docs.speechify.ai/build/guides/concepts/spend-limits.md): Set a monthly USD spend limit on any Speechify API key. Requests are refused with 402 spend_cap_exceeded once the key reaches its limit; the limit resets each calendar month.
- [Projects](https://docs.speechify.ai/build/guides/concepts/projects.md): How Speechify projects work: what a project groups, how a project grant scopes a member, what archive and delete do, and what projects do and do not scope in SpeechifyAI Build.
- [Error Handling and Retries](https://docs.speechify.ai/build/guides/concepts/error-handling.md): Handle Speechify API errors correctly: retry 429, 502, 503, and 504 with exponential backoff; fix 4xx client errors; log the request id.
- [Content Policy](https://docs.speechify.ai/build/guides/concepts/content-policy.md): Speechify screens the text you send for synthesis. A request refused under the content policy returns 400 content_policy_violation or, on a stream already playing, ends early, and is not billed.
- [Safety Identifiers](https://docs.speechify.ai/build/guides/concepts/safety-identifiers.md): Send safety_identifier on Speechify TTS requests to attribute each one to an end user of your application. Abuse can then be limited or blocked for that one user instead of your whole workspace. Send a hash, never an email address.