# AssemblyAI — AI Compare Ninja > Developer platform for file, streaming, short-clip and dictation transcription, speech analysis, LLM access and managed voice agents. ## Overview - **Category:** Audio & Voice (Audio editing & restoration) - **Status:** Active · checked - Active developer API with usage-based billing. - **Paid from:** 0.15 USD / per audio hour; prorated to seconds (Pre-recorded / Universal-2) - **Free access:** One-off free allowance - **Website:** https://www.assemblyai.com/ - **Canonical URL:** https://www.aicompare.ninja/en/tool/assemblyai ## What it does - File transcription, realtime streaming and Sync API for short clips - Dictation API USD 0.62/audio hour including LLM rewrite - Free starter credits, not an ongoing unlimited free API plan - Free: 5 new streams/minute; PAYG starts at 100 and scales automatically - Diarization, Medical Mode, summaries and PII redaction with separate rates - LLM Gateway with model-specific token billing; SSO is a paid add-on ## In brief AssemblyAI provides APIs for prerecorded files, live streams and short synchronous requests. Universal-2 supports 99 languages and Universal-3.5 Pro 18. The Sync API processes up to 2 minutes per request. Diarization, Medical Mode, content analysis and redaction have API-specific extra prices. The Dictation API returns finished text including rewrite at USD 0.62 per audio hour, clips up to 120 s, host dictation.assemblyai.com. It is not Sync, pre-recorded, or streaming STT alone. Product page 19 languages, docs 32. The Voice Agent API bundles Universal-3.5 Pro Realtime, its own conversation model and speech synthesis, turn handling, recordings and hosting. You can connect your own Twilio/SIP service; carrier fees and additional Gateway calls are not paid by that bundle. Realtime and Sync are also offered for self-hosting; your own infrastructure is still required. ## Limits Upload recordings only with the necessary rights and consent. AssemblyAI may use contract-permitted files for its own training after PII redaction, except on EU servers, under a BAA or with opt-out enabled. Current Data Controls are paid-account features offering opt-out, TTL and BAA at no additional charge; changes apply to new requests. Older support text still describes email opt-out and loss of discounts. Streaming zero retention requires training opt-out and does not remove billing metadata. Files, transcripts and Gateway outputs have different retention rules. Streaming scaling raises the next minute's limit by 10% at 70% or greater utilization; this does not promise arbitrary free-tier concurrency. ## Pricing tiers | Tier | Price | Period | What you get | | --- | --- | --- | --- | | Free Credits | free | one-time starter credit | USD 50 credit without expiry; no card required to start; For file/realtime STT, voice agents, Speech Understanding and Guardrails; no LLM Gateway; 5 new streaming connections/minute; no training opt-out, TTL or BAA on free accounts | | Pre-recorded / Universal-2 | 0.15 USD | per audio hour; prorated to seconds | 99 languages; keyterms included; Extra per audio hour: diarization USD 0.02, Medical Mode USD 0.15 | | Pre-recorded / Universal-3.5 Pro | 0.21 USD | per audio hour; prorated to seconds | 18 languages and code switching; wider coverage through Universal-2 fallback; Extra per audio hour: keyterms USD 0.05, prompting USD 0.05, diarization USD 0.02, Medical Mode USD 0.15 | | Realtime / Universal-Streaming English | 0.15 USD | per hour of open connection | English; idle time is billed; Extra per connection hour: keyterms USD 0.04, diarization USD 0.12, Medical Mode USD 0.15 | | Realtime / Universal-Streaming Multilingual | 0.15 USD | per hour of open connection | 6 languages: English, Spanish, German, French, Portuguese, Italian; Extra per connection hour: keyterms USD 0.04, diarization USD 0.12, Medical Mode USD 0.15 | | Realtime / Universal-3.5 Pro | 0.45 USD | per hour of open connection | 18 languages; keyterms included, idle time billed; Extra per connection hour: diarization USD 0.12, prompting USD 0.05, Medical Mode USD 0.15, Voice Focus USD 0.10 | | Sync API | 0.45 USD | per audio hour; prorated to seconds | Up to 2 minutes per request, 18 languages, word timing and confidence; Keyterms and conversation context included; prompting adds USD 0.05 per audio hour | | Dictation API | 0.62 USD | per audio hour; prorated to seconds | USD 0.62 per audio hour, billed per second. LLM rewrite included, no separate token bill; Universal-3.5 Pro. Clips up to 120 s. 19 languages on the product and pricing pages. Host dictation.assemblyai.com. Not Sync, pre-recorded, or streaming STT alone | | Voice Agent API | 4.50 USD | per hour of open connection | Equivalent to USD 0.075/minute, billed per second; own STT/LLM/TTS stack with recordings and hosting; Prompting, Voice Focus, turn/interruption detection included; your Twilio fees and additional Gateway calls separate | | Speaker Identification / Low effort | 0.02 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Speaker Identification / Medium effort | 0.10 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Translation | 0.06 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Custom Formatting | 0.03 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Entity Detection | 0.08 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Sentiment Analysis | 0.02 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Key Phrases | 0.01 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Topic Detection | 0.15 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Summarization / Low effort | 0.02 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Summarization / Medium effort | 0.07 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Profanity Filtering | 0.01 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | PII Audio Redaction | 0.05 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | PII Text Redaction | 0.08 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | Content Moderation | 0.15 USD | per audio hour; prorated to seconds | Add-on; transcription base rate applies separately | | LLM Gateway / GPT-5 Nano | 0.05 / 0.40 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT OSS 20B | 0.07 / 0.30 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Gemini 2.5 Flash Lite | 0.10 / 0.40 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Qwen3.5 4B Fast | 0.10 / 0.50 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / gemma-4-31b | 0.14 / 0.40 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT OSS 120B | 0.15 / 0.60 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Qwen3 32B | 0.15 / 0.60 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Qwen3 Next 80B A3B | 0.15 / 1.20 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Gemini 3.1 Flash Lite | 0.25 / 1.50 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT-5 mini | 0.25 / 2.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Gemini 2.5 Flash | 0.30 / 2.50 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Gemini 3.5 Flash Lite | 0.30 / 2.50 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Gemini 3.7 Flash | 0.75 / 3.75 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Gemini 3.8 Flash | 0.75 / 3.75 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT-5.6 Luna | 1.00 / 6.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Haiku 4.5 | 1.00 / 5.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Gemini 2.5 Pro | 1.25 / 10.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Gemini 3.5 Flash | 1.25 / 9.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT-5 | 1.25 / 10.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT-5.1 | 1.25 / 10.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Gemini 3.6 Flash | 1.50 / 7.50 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT-5.2 | 1.75 / 14.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT-4.1 | 2.00 / 8.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT-5.6 Terra | 2.50 / 15.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Sonnet 4.5 | 3.00 / 15.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Sonnet 4.6 | 3.00 / 15.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Sonnet 5 | 3.00 / 15.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT-5.6 Sol | 4.00 / 20.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / GPT-5.5 | 5.00 / 30.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Opus 4.5 | 5.00 / 25.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Opus 4.6 | 5.00 / 25.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Opus 4.7 | 5.00 / 25.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Opus 4.8 | 5.00 / 25.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | LLM Gateway / Opus 5 | 5.00 / 25.00 USD | per 1M input/output tokens | LLM Gateway, global routing (model_region=global); US/EU regions +10%; Not covered by free credits; additional audio/voice sessions billed separately | | SSO | 199 USD | per connection/month | SAML/OIDC on PAYG and Contract; maximum 1 connection per organization, no SCIM; Full month charged on activation, no prorated refund; PAYG needs sufficient balance and enabled auto-pay | | Custom / Enterprise | contact sales | custom quote | Volume rates, agreed limits and support; contractual scope | | Self-hosted / Realtime + Sync | contact sales | custom quote | Deployment on your own infrastructure; Realtime Universal-3.5 Pro and Sync API; Vendor states the same usage-based cloud rates without a self-hosting premium; clarify infrastructure costs and deployment separately | ## Sources All details regarding plans, limits, and features are based on official vendor documentation and the primary sources verified below. - https://www.assemblyai.com/pricing - https://www.assemblyai.com/docs/billing-and-pricing - https://www.assemblyai.com/docs/getting-started/models - https://www.assemblyai.com/docs/data-controls - https://www.assemblyai.com/docs/data-retention-and-model-training - https://support.assemblyai.com/articles/5930031898-how-to-opt-out-of-data-sharing-for-model-training - https://www.assemblyai.com/docs/sso - https://www.assemblyai.com/deployments/self-hosted - https://www.assemblyai.com/products/dictation-api - https://www.assemblyai.com/docs/dictation - https://www.assemblyai.com/blog/dictation-api --- *Source: AI Compare Ninja (2026) - https://www.aicompare.ninja/en/tool/assemblyai*