SpeechifyAI (Simba 3.2 / 3.0)
Developer API from the Speechify reader company. Cheap per-character pricing ($6-10 per 1M) and a streaming HTTP endpoint; Simba 3.2 is English-only and streaming-native. No text-input WebSocket documented.
Overview
Best for: Low-cost English narration and agents where HTTP streaming per sentence is acceptable.
At a glance
56 ms p50 vendor claim (independent medians 106-123 ms). Price is the Starter plan effective rate ($10 for 1.9M chars); overage $10/1M, Scale $6/1M. simba-3.2 is English only; simba-3.0 covers 6 languages. HTTP output streaming only. Free 500K chars/month.
Text and SSML (pauses, speaking rate)
5 formats including mp3 (per marketing page)
English (simba-3.2) plus 5 more on simba-3.0
Catalog voices (e.g. geffen_32); cloning on paid plans, cloned voices on simba-3.2 need manual approval
Vendor: 56 ms p50 first byte; independent: 106 ms (Coval) and 123 ms (Voice Arena) median time to first audio.
Production US East referenced for latency
Not verified.
Features
- streaming HTTP output
- SSML
- voice cloning (paid)
- batch synthesis (Scale)
- docs MCP server
Pricing
| What | Price | Unit |
|---|---|---|
| Free | $0 | monthly |
| Starter | $10/month | monthly |
| Pro | $99/month | monthly |
| Scale | $499/month | monthly |
900 chars/min at $6 (Scale) to $10 (Starter) per 1M
Free tier: 500K characters/month; commercial use on every plan (vendor)
Source: speechify.ai
Setup
- Sign up at platform.speechify.ai and create an API key.
- POST https://api.speechify.ai/v1/audio/stream with input, voice_id and model.
- Stream the response body to a player.
Endpoint
https://api.speechify.ai/v1/audio/streamAuthentication
Authorization: Bearer <SPEECHIFY_API_KEY>
Quick start python
# pip install requests
import os, requests
r = requests.post(
"https://api.speechify.ai/v1/audio/stream",
headers={"Authorization": f"Bearer {os.environ['SPEECHIFY_API_KEY']}",
"Content-Type": "application/json", "Accept": "audio/mpeg"},
json={"input": "Streaming speech from the Speechify API.",
"voice_id": "geffen_32", "model": "simba-3.2"},
stream=True, timeout=60)
r.raise_for_status()
with open("out.mp3", "wb") as f:
for chunk in r.iter_content(4096):
f.write(chunk)Written from the current docs. Check the vendor's SDK version before you ship.
Warnings
No text-input streaming
Only HTTP output streaming is documented; you must sentence-chunk LLM output and issue one request per chunk.
simba-3.2 is English only
Multilingual needs simba-3.0, which is also the silent default when you omit model.
Old model IDs fail
simba-english and simba-multilingual return 400 model_retired on new workspaces; update older sample code.
Do not confuse with the consumer app
speechify.com is the reader app with separate billing; the API lives at speechify.ai / api.speechify.ai.
Accept header for MP3 is assumed
The snippet sets Accept: audio/mpeg; check the API reference for the exact format selector.
Plus 12 warnings that apply to all text-to-speech, streaming APIs. See category warnings.
Limits
- /v1/audio/stream up to 20,000 characters; /v1/audio/speech up to 2,000
- Free tier cannot top up
Models and products
| Name | Status |
|---|---|
| simba-3.2 | GA (recommended for English) |
| simba-3.0 | GA (default when model omitted) |
| simba-english / simba-multilingual | Retired |
Docs and sources
Docs
Sources used
Exact audio format parameter name and list; concurrency limits.