> 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-3.5` (48 languages under one id, English included; recommended), `simba-3.2` (English) 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 # Speech Synthesis Markup Language (SSML) > Use SSML with SpeechifyAI Build TTS to set pauses, speaking rate, pitch, volume and pronunciation. See which tags each model applies and how to escape characters. SSML is an XML-based markup language for controlling how text is spoken. On the current models, `simba-3.5`, `simba-3.2` and `simba-3.0`, it sets pauses, speaking rate, pitch, volume and pronunciation. Wrap your content in a `` tag: ```xml Your content to be synthesized here ``` ## Escaping Characters Transforming text into SSML requires escaping certain characters to ensure correct interpretation: | Character | Escaped Form | | --------- | ------------ | | `&` | `&` | | `>` | `>` | | `<` | `<` | | `"` | `"` | | `'` | `'` | **`Example`** ```xml title="Example" Some "text" with 5 < 6 & 4 > 8 in it ``` **`Escape Function`** ```ts title="Escape Function" const escapeSSMLChars = (text: string) => text .replaceAll("&", "&") .replaceAll("<", "<") .replaceAll(">", ">") .replaceAll('"', """) .replaceAll("'", "'"); ``` > **Note** > > An attribute name or value we do not recognise is **ignored, not refused**. `` (misspelled name) and `` (misspelled value) both synthesize as ordinary speech and return `200`. Malformed XML is different: unbalanced tags or undeclared entities return `400`. If a tag seems to have had no effect, check the spelling of both the attribute name and its value. ## What each model applies | Tag | `simba-3.5`, `simba-3.2`, `simba-3.0` | Simba 1.6 (`simba-english`, `simba-multilingual`) until `2026-11-21` | | ------------------------------------- | ------------------------------------- | -------------------------------------------------------------------- | | `` | Applied | Applied | | `` | Applied | Applied | | `` | Applied | Applied | | ``, `` | Applied | Applied | | `` | Accepted, not applied | Applied | | `` | Accepted, not applied | Applied | Accepted, not applied means the request still returns `200` and the text inside the tag is spoken, without the change the tag describes. Simba 1.6 is retired for new workspaces. From `2026-11-21` both of its ids are served by the current models, so they apply only the tags in the current-model column. See [Migrating off Simba 1.6](/build/migrating-off-simba-1-6). ## Supported SSML Tags #### prosody The `prosody` tag changes how a span is spoken. Every model applies `rate`, `pitch` and `volume`, with the same values. Nested `prosody` tags multiply: `rate="slow"` inside `rate="slow"` is 0.75 times 0.75 of the normal rate. A `prosody` around a whole block of text costs nothing extra. One that changes part of a sentence has that part synthesized on its own, so the sentence's intonation can break where the value changes. ```xml This is a normal speech pattern. I'm speaking faster than usual! Back to normal speech pattern. ``` **Parameters** **`rate`** `string` Alters speech speed. **Values:** * `x-slow`, `slow`, `medium` (also `default`), `fast`, `x-fast` * Percentage adjustments: `-50%` to `+9900%` (e.g., `+20%`, `-30%`) --- **`pitch`** `string` Adjusts the pitch of speech delivery, without changing its speed. **Values:** * `x-low`, `low`, `medium` (also `default`), `high`, `x-high` * Percentage adjustments: `-83%` to `+100%` (e.g., `+20%`, `-30%`) --- **`volume`** `string` Controls speech loudness. A gain that would clip is held under a limiter. **Values:** * `silent`, `x-soft`, `soft`, `medium` (also `default`), `loud`, `x-loud` * Decibel adjustments: Number with `dB` suffix, `-60dB` to `+20dB` (e.g., `-6dB`) * Percentage adjustments, relative to the voice's own loudness: `-100%` to `+900%` (e.g., `+20%`, `-30%`). `100%` doubles the gain; it does not mean unchanged. Omit `volume`, or use `medium`, for no change. --- #### break The `break` tag controls pausing between words, following [W3 specifications](https://www.w3.org/TR/speech-synthesis11/#S3.2.3). ```xml Sometimes it can be useful to add a longer pause at the end of the sentence. Or sometimes in the middle. ``` **Parameters** **`strength`** `string` Specifies pause strength. **Values:** * `none`: 0ms * `x-weak`: 250ms * `weak`: 500ms * `medium`: 750ms * `strong`: 1000ms * `x-strong`: 1250ms --- **`time`** `string` Specifies pause duration (0-10 seconds). A single break is capped at 10 seconds, and the **total** silence one document may insert is capped at **30 seconds** - past that, further pauses are dropped rather than rejected. **Values:** * Milliseconds: `ms` suffix (e.g., `100ms`) * Seconds: `s` suffix (e.g., `1s`) --- #### emphasis The `emphasis` tag adds or removes emphasis from text, modifying speech similarly to `prosody` but without setting individual attributes. Simba 1.6 only: `simba-3.5`, `simba-3.2` and `simba-3.0` accept it and speak the text without emphasis. ```xml I already told you I really like that person. ``` **Parameters** **`level`** `string` Specifies emphasis level. **Values:** * `reduced` * `moderate` * `strong` --- #### sub The `sub` tag replaces pronunciation for contained text, following [W3 specifications](https://www.w3.org/TR/speech-synthesis11/#S3.1.11). ```xml For detailed information, please read the FAQ section. ``` **Parameters** **`alias`** `string` — required Specifies text to be spoken instead of enclosed text. --- #### speechify:style The `speechify:style` tag sets an emotion style. Simba 1.6 only: `simba-3.5`, `simba-3.2` and `simba-3.0` accept it and speak the text without the style. See [Emotion styles](/build/guides/text-to-speech/emotion-control). ```xml Great news! Your order shipped! ``` **Parameters** **`emotion`** `string` Sets the voice emotion on Simba 1.6. Values: `angry`, `cheerful`, `sad`, `terrified`, `relaxed`, `fearful`, `surprised`, `calm`, `assertive`, `energetic`, `warm`, `direct`, `bright`. --- ## Examples #### Basic SSML ```xml Welcome to SpeechifyAI Build. ``` #### Speaking rate ```xml This text will be spoken slowly. While this text will be spoken quickly. ``` #### Pauses ```xml Let me tell you something important. This is critical information. ``` #### Pronunciation ```xml Read the FAQ before you call. ``` To say a word your way everywhere it appears, or to give its exact phones, send [`pronunciations`](/build/guides/text-to-speech/pronunciation) with the request on Simba 3.5.