Free speech-to-text & TTS APIs (2026)

Free tier: Free $200 credit, no credit card required, no expiration stated ("No minimums. No expiration."), then pay-as-you-go.

• Auth: API key (Token)
• Serving public users: Yes.
• Note: STT, TTS and voice agent APIs share the credit.
• Source: deepgram.com

Free tier: Free tier, no credit card: up to 185 hours of pre-recorded transcription and up to 333 hours of streaming transcription.

• Auth: API key (Authorization header)
• Serving public users: Yes.
• Source: www.assemblyai.com

Free tier: Free plan: 10,000 characters/month included (~10 minutes of TTS).

• Auth: API key (xi-api-key)
• Serving public users: Unknown on this page (check free-plan licence).
• Note: Commercial-use/attribution terms for the free plan are not stated on this page: unknown.
• Source: elevenlabs.io

Free tier: Start with €50 free credits (self-serve async and real-time STT).

• Auth: API key (x-gladia-key)
• Serving public users: Yes.
• Source: www.gladia.io

Free tier: Start free with $100 in credits, no card required; real-time free accounts limited to 2 concurrent sessions; TTS: first 1 million characters free (~20 hours).

• Auth: API key (Bearer)
• Serving public users: Yes.
• Source: www.speechmatics.com

Free tier: Part of Groq free plan: whisper-large-v3 and whisper-large-v3-turbo at 20 RPM, 2K RPD, 7,200 audio-seconds/hour, 28,800 audio-seconds/day.

• Auth: API key (Bearer), OpenAI-compatible /audio/transcriptions
• Serving public users: See Groq API.
• Note: Same key/account as Groq LLM API.
• Source: console.groq.com