iSpeech vs Voicebox

iSpeech provides text-to-speech and automated speech recognition through APIs, SDKs, and online tools. Its speech API can synthesize audio with multiple voices, formats, bitrates, frequencies, and playback speeds, and supports MathML and SSML. The API can also transcribe submitted audio across multiple languages and recognition models; iSpeech says custom models can be created. The homepage lists support for more than 30 languages. Audio downloads are available in AIFF, MP3, OGG, WMA, FLAC, WAV, A-law, μ-law, VOX, and MP4 formats. Listed access includes Android, iOS, Linux, macOS, web, Windows, API, and extension. The Basic plan is free for personal use, and commercial use is listed as available. Plus costs $2.95 a month, billed monthly, and includes 30-minute recordings, approximately 4,167 words. Premium costs $3.95 a month, billed monthly, with 12-hour recordings, approximately 100,000 words. Pay Per Use costs $50 a month for dynamic TTS usage only and includes 2,000 credits. Pay Per Install costs $0.25 a month and has a 10,000-install minimum.

Voicebox is a free, open-source local AI voice studio for voice cloning, speech generation, dictation, and agent voice output. Its desktop app can clone a voice from as little as three seconds of audio, supplied by file, microphone recording, or system capture. The maker lists seven text-to-speech engines for cloning, preset voices, and delivery control. A timeline editor supports multi-voice narratives, arranging tracks, trimming clips, and mixing conversations; effects include pitch shift, reverb, delay, and compression. Dictation uses a global shortcut to send transcripts to the focused text field or clipboard, with local Whisper models supporting 99 languages. MCP-aware agents such as Claude Code, Cursor, and Cline can speak through Voicebox, and a local REST API provides speech generation and related functions. The privacy policy says the offline desktop app requires no account and does not send recordings, profiles, transcripts, generations, or settings to the maker. Local is free with unlimited local generations and captures. Cloud and mobile sync are marked as coming soon, and cloud pricing and limits are not final.