AssemblyAI vs Deepgram

Tagline

Build with accurate speech recognition and voice AI models through modular and easy-to-integrate APIs.

Scalable Speech-to-Text, Text-to-Speech & Voice Agent APIs with simple, transparent billing.

Category

Pricing

Rating

Platforms

API

Open source

Description

AssemblyAI is a voice AI infrastructure platform providing accurate transcription models. It offers developer APIs for Speaker Diarization, Language Detection, Real-time Streaming STT, Auto Chapters, Sentiment Analysis, and Conversational Voice Agents.

Deepgram is a developer-first Voice AI platform offering highly accurate, scalable Speech-to-Text (STT), Text-to-Speech (TTS), and Voice Agent APIs. Built for real-time and batch workflows, Deepgram supports over 45 languages, advanced features like Speaker Diarization, Smart Formatting, and Audio Intelligence models, combined with true per-second billing and enterprise-grade security.

Key features

• Speaker Diarization
• Automatic Language Detection
• Pre-recorded Speech-to-Text
• Real-time Streaming STT
• Synchronous Short STT
• Voice Agent API
• Sentiment Analysis
• Auto Chapters
• PII Redaction
• Profanity Filtering
• Medical Mode
• Voice Focus

• Speech-to-Text
• Text-to-Speech
• Voice Agent API
• Speaker Diarization
• Smart Formatting
• Keyterm Prompting
• Automatic Language Detection
• Sentiment Analysis
• Topic Detection
• Summarization
• Intent Recognition
• Redaction

Pros

• Achieves a low 2.9% speaker diarization error rate.
• Supports multilingual speaker diarization across 95 languages.
• Language detection API supports 99 different languages.
• API integration is simple, requiring less than 10 lines of code to get started.
• Supports both pre-recorded audio and real-time streaming speech-to-text.
• Voice Agent API enables deployable conversational voice agents over browser or phone.
• Provides specialized features like Auto Chapters, Sentiment Analysis, PII Redaction, and Medical Mode.
• Integration capabilities with LiveKit, Pipecat, and Twilio are supported.

• Provides a generous $200 free credit to new accounts that does not expire after 12 months.
• Employs true per-second billing without rounding up to the nearest minute or 15 seconds.
• Charges the exact same low rate for both real-time streaming and pre-recorded (batch) transcription.
• SOC 2 Type 2 certified and HIPAA compliant, with BAAs available for Enterprise customers.
• Provides options to deploy on-premise or in private clouds via self-hosted containers.
• Offers a Growth plan starting at $4k/year that unlocks up to approximately 20% discount across products.
• Aura TTS Billing is done by input character, facilitating precise cost controls.
• Supports automatic multilingual transcription and code-switching via Nova's multilingual models.
• Allows refunds on unused purchased credits within 30 days of purchase.

Cons

• Specific pricing schedules and tier rates are not listed within the crawled snippets.
• No free-tier usage limits or trial size details are disclosed in the retrieved content.
• No mobile-native SDKs (like iOS or Android) are explicitly referenced in the documentation index.
• The exact compliance certifications (such as SOC2 or HIPAA) are not verified in the snippets.
• The core transcription models are proprietary and not provided as open source.

• Self-hosted container deployments are restricted to Enterprise tier and require dedicated NVIDIA GPUs.
• Promotional or free credits are completely non-transferable under all circumstances.
• Purchased credits are non-refundable once they pass the 30-day mark.
• No refunds or adjustments are provided for incorrect or faulty audio files uploaded due to user-side system/coding errors.
• Exceeding currency limits on Pay-As-You-Go plans may cause requests to be queued or rejected.
• Multichannel audio billing scales by total processed duration (e.g., 2 channels for 10 minutes equals 20 minutes of billable time).

Pricing plans

• Pay As You Go—
  • • Free $200 Credit then pay-as-you-go
  • • No minimums
  • • No expiration
  • • No credit card required
• GrowthUSD4000/year
  • • $4K+/ year
  • • With pre-paid credits for the year
  • • Credits are redeemed against actual usage
  • • Growth usage rates shown for STT, TTS, Voice Agent API, and Audio Intelligence
• Enterprise—
  • • For businesses with large volumes
  • • For data or deployment requirements
  • • For support needs
  • • Enterprise-grade trust and compliance options

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