HeyGen Voice vs Murf TTS API + MCP

HeyGen Voice

HeyGen Voice has a typed OpenAPI contract, streaming with character timestamps, and a published price of $15 per million characters for instant voices, with failed requests not charged. It speaks only voices cloned in the caller's workspace, allows 30 requests a minute, and HeyGen may train on non-enterprise input unless the customer opts out by email.

Murf TTS API + MCP

Falcon 2 costs 1 cent per 1,000 characters on pay as you go, with a $2 minimum purchase. Falcon 2 concurrency is 2 outside US-East on free and pay as you go, 5 on US-East.

HeyGen Voice

1. Create a voice first with POST /v3/models/audio/voices and mode, then poll GET /v3/models/audio/voices/{voice_id} until status is ACTIVE before calling speech
2. Send expressiveness_boost only for instant voices and seed, speed, pitch_shift, pitch_variance or <break> tags only for professional voices. Mixing them returns 400 invalid_parameter
3. On the stream, decode and play each base64 WAV part in part_index order. Do not concatenate the bytes
4. Send an Idempotency-Key when creating a voice, and retry 502, 503 and 504 on speech, which the OpenAPI file marks as safe
5. Use POST /v3/voices/speech for stock or designed voices. It is a different engine and price

Murf TTS API + MCP

1. Send locale on every request, since multiNativeLocale was replaced on 2026-03-05.
2. Split text into chunks under 3,000 characters per request.
3. Use the US-East host for 5 concurrent Falcon 2 calls instead of 2.
4. Set encodedAsBase64 to get audio inline and skip the expiring download link.
5. Back off on 429 and close WebSocket contexts with end: true to free slots.