{"name":"AssemblyAI","tagline":"Speech-to-text and voice-agent APIs — Universal-3.5 Pro, streaming billed on socket time.","url":"https://www.assemblyai.com","category":"audio","pricing":"freemium","price_note":"$50 free credits (no card); Universal-3.5 Pro $0.21/hr async / $0.45/hr streaming; Voice Agent API $4.50/hr all-in; add-ons stack","free_tier":true,"open_source":false,"api":true,"self_host":false,"model_routing":"bundled","verdict":"situational","verdict_text":"A real STT rate card, not a homepage teaser. Async Pro is $0.21/hr; streaming Pro is $0.45/hr on WebSocket open time (idle counts). Voice Agent is $4.50/hr bundled. EU region is the same price. $50 credits get you a prototype. Not Deepgram, not Whisper on your GPU.","limitations":["Streaming bills session duration, not speech duration — leaving a socket open is a bill.","Multichannel audio is billed per channel (stereo = 2×).","Add-ons stack on the base rate; diarization/PII/medical are extra meters.","Free-tier streaming concurrency is 5 new streams/min vs 100 on pay-as-you-go."],"strengths":["Transparent per-hour rate card ($0.21 async / $0.45 streaming / $4.50 voice agent).","$50 free credits let you prototype without a card.","Voice Agent API bundles everything at one hourly rate."],"use_for":["Prototyping STT or voice agents on the $50 credit pool.","Async transcription jobs where per-hour cost is the main metric.","Real-time streaming when you can tolerate session-duration billing."],"skip_when":["You need streaming billed by speech time, not idle WebSocket time.","Multichannel audio would multiply the hourly rate beyond budget.","Free-tier streaming concurrency (5 streams/min) would be the production path."],"receipts":["https://www.assemblyai.com/pricing","https://www.assemblyai.com/docs"],"affiliate":"none","evidence_tier":"source-verified","momentum":"steady","featured":false,"last_verified":"2026-08-24","observed_by":"whysanesanders","slug":"assemblyai","canonical_url":"https://noemium.com/tools/assemblyai/","attribution":"Noemium catalog data is licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). See https://noemium.com/method/ for how entries are verified."}