OpenAI's TTS produces high-quality, steerable voices but meters by tokens rather than characters, so cost takes estimation. SpeechifyAI bills from $6 per 1M characters with no token math, adds voice cloning that OpenAI does not offer, and ships many more voices.
| Capability | Speechify | OpenAI Text-to-Speech |
|---|---|---|
| Price (per 1M chars) | From $6 / 1M | gpt-4o-mini-tts token-metered: $0.60 per 1M input tokens, $12 per 1M audio output tokens |
| Pricing model | Flat per character; no token math | Token-metered; you tokenize the script to estimate cost |
| Voice quality | Proprietary neural voice models | High-quality, expressive voices; steerable via instructions |
| Voices | 1,500+ | 13 built-in voices (page intro confusingly says 11) |
| Languages | 30+ | Multilingual; varies by voice |
| Voice cloning | Professional voice cloning included | No cloning of arbitrary voices; built-in voices only |
| Latency | Sub-300ms first byte, streaming | Streaming supported; latency varies |
| Commercial use / free tier | Commercial use on every plan; 50K chars/month free | Commercial use; no standing free tier for the API |
OpenAI bills TTS by tokens: $0.60 per million input tokens and $12 per million audio output tokens. Estimating a project cost means tokenizing the script and multiplying, then hoping the tokenizer behaves the same way on the day of the invoice. SpeechifyAI bills per character: a million characters is a million characters, the invoice matches the number the team computed when sizing the project, with no tokenizer math and no model-specific multiplier.
OpenAI ships 13 built-in voices (the docs intro still confusingly says 11), and the custom voices program is closed to most customers. SpeechifyAI ships 1,500+ voices in the catalog with professional voice cloning included on Starter and above: upload audio, train the voice, use it the same day on the same per-character rate. The instruction-steerable feel OpenAI is known for is covered by SpeechifyAI's emotion control plus SSML in the same API.
SpeechifyAI is from $6 per million characters on flat per-character billing, with professional voice cloning included on Starter and above and a 1,500+ voice catalog covering 30+ languages, on streaming first byte under 300ms.