Simba 3.5 is SpeechifyAI's recommended text-to-speech model from 21 October 2026: 48 languages under one model id, simba-3.5, on every plan and every synthesis endpoint. The request, the languages, the price and how to switch from Simba 3.2.
SpeechifyAI's text-to-speech API takes an optional safety_identifier, a keyed hash of your own user id, so one end user can be limited or blocked while the rest of your workspace keeps working. On 13 October 2026, seven other TTS APIs documented no way to do that.
Since 9 October 2026, SpeechifyAI takes an LLM's reply over a WebSocket as it is written. From Google Cloud us-east4 that day, the first word was audible 49 ms after the LLM finished its first sentence, against 68 ms with one HTTP request per sentence.
On 1 October 2026, SpeechifyAI's $10 Starter plan allowed 15 concurrent text-to-speech requests and its $99 Pro plan 30. Concurrency and rate limits for 14 text-to-speech APIs, plan by plan, read from each provider's own pages that day.
LiveKit's Speechify plugins, for Python and Node.js, add Speechify TTS to an AgentSession in one line. The Python plugin streams each sentence: 98 ms median to first audible audio from US East on 12 Oct 2026.
In our own round on 9 October 2026, Simba 3.2 reached first audible audio in a median of 47 ms from US East, the lowest of the 13 streaming endpoints we timed. What to measure before you pick a TTS API for a voice agent, and what cuts the wait.
Monthly cost of 13 text-to-speech APIs at 1M, 10M and 100M characters, subscription fees included, read from each vendor's pricing page on 28 September 2026, next to each model's blind-listening score.
There's now a command line for Speechify. Install it from npm, log in with your API key, and synthesize speech, browse voices, and hand Speechify to your AI agent, all from your terminal.
Speechify's official LiveKit plugin streams word-level timestamps alongside the audio. Read them by overriding transcription_node and you get word-synced captions in a Python voice agent, with no extra API calls.
What streaming text-to-speech makes possible: read-aloud, voice agents, call narration, live captions, and read-along highlighting, all built on the Speechify streaming endpoints.
Give the Speechify text-to-speech API a URL and the page comes back as narrated audio. Fetch, extract the article text, chunk on sentence boundaries, synthesize each chunk with POST /v1/audio/speech.
What engineers actually use to add voice to web and mobile apps, and the four decisions that matter: the browser's built-in API versus a cloud one, streaming versus batch, where the key lives, and how to keep audio playing on iOS.
The tools for producing narration without hiring voice actors, compared on cost per finished hour rather than per seat. Studio subscriptions cap downloaded minutes; per-character APIs do not. One hour of audio runs from $0.31 to $40 depending on which you pick.
Which speech platform to pick when your chatbot has to talk. The decision is not voice quality, it is whether you need a TTS API or a full voice agent, plus how the model reads account numbers and order IDs back to a caller.
Generate the same script in English, German, Spanish, French, Italian, and Portuguese with the Speechify TTS API. Pick a simba-3.0 voice for each locale, call POST /v1/audio/speech per language, keep the key server-side.
How a Speechify provider for the AI SDK's generateSpeech() works: a dependency-free speech model that maps POST /v1/audio/speech onto SpeechModelV4, key held server-side in a Next.js route. Speechify now maintains one on npm, @speechify/ai-sdk-provider.
simba-3.2 is Speechify's streaming-native English TTS model, and GET /v1/audio/models lets you discover models at runtime instead of hardcoding a list. Since 21 October 2026 the recommended model is simba-3.5. What shipped, which voices 3.2 serves, and how to move.
Simba 3.2 for voice agents and narration at volume: 47 ms to first audible audio from US East on 9 October 2026, and $10 per 1M characters, $6 on Scale. Simba 3.5 (21 October 2026) speaks 48 languages with every catalog voice.
Use SSML pauses, speaking rate, and pronunciation aliases to shape Speechify TTS output from one API request, and know which tags current models apply.
On the Artificial Analysis Speech Arena on 13 October 2026, Simba 3.2 scored 1,244 and was the lowest-priced model in the top ten, at $6.60 per million characters against $11 for the next. How the board's Elo works, and two independent latency readings.
Turn long-form ePub or Markdown into a single narrated chapter MP3 with a runnable Python demo: chunk on sentence boundaries, synthesize each chunk, stitch with ffmpeg.
How to stream audio from the Speechify TTS API in Python with plain HTTP and requests. Covers chunked streaming to disk and piping audio to a player without waiting for the full payload.
A practical guide to synthesizing speech in Node.js using the Speechify TTS API. Covers installation, a basic synthesis call, streaming audio to disk, and what to reach for next.
SpeechifyAI teamFirst published by Luke Oliff
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