Best voice APIs for AI agents in 2026: text to speech and transcription compared

Text to speech API pricing compared

Voice APIs price speech per character or per token and transcription per minute, and their plans bundle credits differently, so the table converts everything to the same units: dollars per million characters, per hour of generated speech, and per hour of transcribed audio. Ork doesn't charge for voice; you connect your own key and the provider bills you.

Prices in US dollars from each provider's pricing page, checked November 2026. An hour of speech is taken as about 54,000 characters (150 words a minute); real voices run a little faster or slower. Fish Audio bills per UTF-8 byte, which is one byte per character in English.

What a talking AI agent costs a month

The worked example is one bot that reads about 30 minutes of replies aloud each day and transcribes about 30 minutes of what you say, every day for a month: 15 hours of speech (about 810,000 characters) and 15 hours of transcription.

Speech is usually the larger charge, so how much your bots say matters more than how much you say. The exception is where a free speech allowance covers most of the month, as with Google and Azure here, which leaves transcription as the main cost. In Chrome on a desktop or in the mobile app, your device often does the transcription for free. A self-hosted Ork can also set VOICE_SUMMARY_MIN_CHARS so long replies are read as a short summary instead of in full.

Usage prices from each provider's pricing page, checked November 2026. Where speech is bought as a monthly plan, as with Cartesia, the cost shown is the fee for the smallest plan that covers it. Ork doesn't charge for voice: you connect your own key and the provider bills you.

What each option does in Ork

Voice APIs Ork doesn't connect to

Plenty of good voice APIs have no built-in connection in Ork. Here is how they compare, so you can judge what you'd be missing.

• Deepgram is best known for transcription: Nova-3 costs $0.26 an hour in batch and $0.46 streaming, with a $200 starting credit, and many voice agents use it to listen. Its Aura-2 voices cost $30 per million characters and sound plainer than ElevenLabs. It uses its own API, not OpenAI's.
• Google Cloud's Chirp 3 HD voices cost $30 per million characters with the first 1M free each month, and its Speech-to-Text costs about $0.96 an hour. Gemini's speech models are billed per token.
• Azure AI Speech has neural voices at $15 per million characters, HD voices at $22, and transcription from $0.18 an hour in batch, with a monthly free tier of 0.5M characters and 5 hours.
• Amazon Polly's neural voices cost $16 and generative voices $30 per million characters. Amazon Transcribe costs about $0.36 an hour in batch.
• Inworld sells low-cost voices for agents, $15 to $25 per million characters. Hume's Octave focuses on emotional delivery; its rates were no longer on its pricing page in November 2026.
• AssemblyAI ($0.15 to $0.45 an hour) and Groq's hosted Whisper ($0.04 an hour) are strong for transcription. Groq serves OpenAI's audio API shape, so it may be reachable through Self-hosted, but Ork would send speech there too.
• PlayHT, once a common ElevenLabs alternative, shut down its platform and API at the end of 2025.