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Deepgram is Bolna’s default transcriber for English. Its streaming Nova-3 model delivers sub-150ms transcription latency, making it the fastest option for real-time voice AI.

Quick config

Set this in your agent’s tools_config.transcriber block. See Create Agent API for the full schema. To use your own Deepgram account, connect it at platform.bolna.ai/auth/deepgram.

Supported models

Recommendation: Use nova-3 for English agents. Use nova-2 with language set explicitly for non-English.

Key settings

Endpointing guidance

  • 250ms — default; works well for fluent English speakers
  • 350–500ms — better for non-native speakers, elderly callers, or callers who pause mid-sentence
  • 100–150ms — fast-paced scripts; reduces dead air but may interrupt on pauses

Multilingual config

Set language explicitly. Auto-detect adds 100–200ms latency and occasionally misclassifies.
For Indian languages, Sarvam may give better accuracy. See Multilingual Voice Agents.

FAQ

Use nova-3 for English — it’s faster and more accurate. Use nova-2 when you need a non-English language or a domain-specific variant (nova-2-phonecall, nova-2-medical, etc.).
Your endpointing value is too low. Increase it to 350–500ms. If callers have a strong accent or speak with filler words (“um”, “uh”), a higher endpointing value gives them more time to complete their thought.
Match the telephony provider’s output: Plivo and Exotel use linear16 at 16000 Hz. Twilio uses mulaw at 8000 Hz. If you use the wrong values, transcription accuracy degrades.
Yes — the same transcriber config applies to both outbound and inbound calls. There’s no separate configuration.