Pick AssemblyAI if
voice-product engineers who will pick Universal-3.5 Pro vs Universal-2 and close the socket.
Read the AssemblyAI pageAssemblyAI vs Speechmatics
Our take
Pick AssemblyAI if you're voice-product engineers who will pick Universal-3.5 Pro vs Universal-2 and close the socket. Pick Speechmatics if you're on a voice-agent and compliance team who will spend the $100 credits and then pay $/hr. Skip AssemblyAI if you're people who want a local MIT model (OpenAI Whisper) with no vendor invoice. Skip Speechmatics if you're people who want a VO file (Listnr) or MIT local STT
AssemblyAI
Voice AI API (pre-recorded STT
Best for
AssemblyAI Hours of audio billed on a rate card
Speechmatics Batch or realtime STT with a public $/hr
Free plan
AssemblyAI $0 · $50, no credit card. Free-tier streaming concurrency 5 new streams/min vs PAYG 100
Speechmatics No free plan
Lowest paid
AssemblyAI Universal-2 (pre-recorded) $0.15
Speechmatics TTS $0.011
Next step up
AssemblyAI Universal-3.5 Pro (pre-recorded) $0.21
Speechmatics Melia 1 $0.24
Coding agent
AssemblyAI Voice Agent API
Speechmatics Linden 1
Watch out
AssemblyAI Streaming bills idle socket time
Speechmatics $100 credits expire in 12 months
Last checked
AssemblyAI 2026-10-20 · assemblyai.com/pricing
Speechmatics 2026-10-27 · speechmatics.com/pricing
Which one, then?
Pick Speechmatics if
voice-agent and compliance teams who will spend the $100 credits and then pay $/hr.
Read the Speechmatics page