Uploaded August 2026 | Updated September 2026, 3 weeks ago
AssemblyAI's Universal 3.5 Pro is now available as a transcriber option in Vapi, bringing real-time speech-to-text with keyword boosting, a promptable model, and multilingual support to your voice agents.
In this walkthrough, David Lange shows how to:
Select Universal 3.5 Pro as your transcriber provider inside a Vapi assistant's settings
Boost recognition of up to 100 custom terms — names, jargon, product terminology — with keyword boosting
Use the new mode parameter to balance accuracy and latency without manually tuning individual settings
Prompt the model with domain, topic, or scenario context to steer transcription
Pass language codes to steer transcription toward specific languages and support code-switching across the 18 languages Universal 3.5 Pro supports
Then, see it in action: a live conversation with a voice agent built for a receptionist use case, using agent context and prompt/key terms for more accurate, personalized transcription.
Get started: docs.vapi.ai/providers/transcriber/assembly-ai?utm_source=youtube&utm_medium=video&utm_campaign=universal_3_5_pro_vapi_demo
0:00 Intro
0:12 Open the transcriber settings in a Vapi assistant
0:25 Select Universal 3.5 Pro
0:38 Keyword boosting: up to 100 custom terms
0:55 Advanced settings: the new mode parameter
1:10 Prompt feature: adding context
1:25 Language codes and code-switching (18 languages)
1:40 Live demo: talking to the voice agent
2:45 Wrap-up
▬▬▬▬▬▬▬▬▬▬▬▬ CONNECT ▬▬▬▬▬▬▬▬▬▬▬▬
🖥️ Website: assemblyai.com
🐦 Twitter: twitter.com/AssemblyAI
▶️ Subscribe: youtube.com/c/AssemblyAI?sub_confirmation=1
🔥 We're hiring! Check our open roles: assemblyai.com/careers
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#AssemblyAI #Universal35Pro #Vapi #VapiAssemblyAIIntegration #VoiceAI #SpeechToText #RealTimeTranscription #VoiceAgent #AIVoiceAgents #SpeechToTextAPI #KeywordBoosting #CodeSwitching #MultilingualSpeechRecognition #ReceptionistAIAgent #BuildAVoiceAgent
AssemblyAI's Universal 3.5 Pro is now available as a transcriber option in Vapi, bringing real-time speech-to-text with keyword boosting, a promptable model, and multilingual support to your voice agents.
In this walkthrough, David Lange shows how to:
Select Universal 3.5 Pro as your transcriber provider inside a Vapi assistant's settings
Boost recognition of up to 100 custom terms — names, jargon, product terminology — with keyword boosting
Use the new mode parameter to balance accuracy and latency without manually tuning individual settings
Prompt the model with domain, topic, or scenario context to steer transcription
Pass language codes to steer transcription toward specific languages and support code-switching across the 18 languages Universal 3.5 Pro supports
Then, see it in action: a live conversation with a voice agent built for a receptionist use case, using agent context and prompt/key terms for more accurate, personalized transcription.
Get started: docs.vapi.ai/providers/transcriber/assembly-ai?utm_source=youtube&utm_medium=video&utm_campaign=universal_3_5_pro_vapi_demo
0:00 Intro
0:12 Open the transcriber settings in a Vapi assistant
0:25 Select Universal 3.5 Pro
0:38 Keyword boosting: up to 100 custom terms
0:55 Advanced settings: the new mode parameter
1:10 Prompt feature: adding context
1:25 Language codes and code-switching (18 languages)
1:40 Live demo: talking to the voice agent
2:45 Wrap-up
▬▬▬▬▬▬▬▬▬▬▬▬ CONNECT ▬▬▬▬▬▬▬▬▬▬▬▬
🖥️ Website: assemblyai.com
🐦 Twitter: twitter.com/AssemblyAI
▶️ Subscribe: youtube.com/c/AssemblyAI?sub_confirmation=1
🔥 We're hiring! Check our open roles: assemblyai.com/careers
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
#AssemblyAI #Universal35Pro #Vapi #VapiAssemblyAIIntegration #VoiceAI #SpeechToText #RealTimeTranscription #VoiceAgent #AIVoiceAgents #SpeechToTextAPI #KeywordBoosting #CodeSwitching #MultilingualSpeechRecognition #ReceptionistAIAgent #BuildAVoiceAgent
