Head-to-head
AssemblyAI vs Sonix
AssemblyAI uniquely has 5 features · Sonix uniquely has 3 features.
The verdict
AssemblyAI or Sonix?
Section 01
Pricing, plan by plan
Every plan each vendor publishes, monthly and yearly where both are offered.
AssemblyAI
Free Tier
Free
Up to 185 hours pre-recorded transcription and 333 hours streaming transcription, no credit card required
Universal-3.5 Pro
$0.15/hr
Highly accurate STT model, 99 languages, 12.5M+ hours training data, no minimum commitment
Universal-3.5 Pro
$0.21/hr
Most accurate async STT model, 18 languages, native code-switching, best-in-class speaker diarization
Enterprise / Custom
Custom
Custom rate limits, enhanced concurrency, enterprise-grade flexibility, volume discounts, AWS Marketplace available
Sonix
Pay As You Go
$10/hr
No subscription; pay per audio hour; 5 GB storage; single-user; no AI workspace
Core
$25/mo · $275/yr
5 hrs/mo transcription & translation; 5 hrs/mo AI workspace; 25 GB storage; 1 user
Advanced
$50/mo · $550/yr
20 hrs/mo transcription & translation; 25 hrs/mo AI workspace; 50 GB storage; 1 user
Pro
$80/mo · $880/yr
40 hrs/mo transcription & translation; 100 hrs/mo AI workspace; 100 GB storage; 1 user
Enterprise
Custom
Everything in Pro plus SOC 2, HIPAA, SSO/SCIM, audit logs, 1 TB storage, unlimited members, dedicated account manager
Section 02
Pros and cons
From each tool's full review, written from the same checked facts.
AssemblyAI
Pros
- Universal-3.5 Pro model supports native code-switching across 18 languages with an exceptionally fast real-time factor of 0.008x, making it viable for demanding production environments.
- Comprehensive API-first platform that goes well beyond transcription, including speaker diarization, sentiment analysis, topic detection, entity recognition, and PII redaction.
- Pre-recorded transcription API supports 99 languages via the Universal-2 model, offering broad global coverage.
- Includes a Voice Agent API and an LLM gateway that allows routing to models like GPT or Claude within the same pipeline.
- Medical Mode is available, indicating deliberate positioning for healthcare use cases with specialized transcription needs.
- Real-time streaming transcription is supported alongside pre-recorded audio, giving developers flexibility across different application types.
- Strong adoption among developers and engineering teams, with active discussion in forums and a reported user base of millions of developers.
Cons
- No consumer-facing dashboard — users cannot simply upload an audio file and download a transcript without developer setup.
- No text-to-speech, voice cloning, or music generation capabilities, limiting use cases strictly to speech input and understanding output.
- Limited public feedback on the Medical Mode feature makes it difficult to assess its real-world accuracy and reliability.
- The product is entirely API-first, meaning non-technical buyers or small teams without engineering resources are effectively excluded.
- Code-switching in the Universal-3.5 Pro model is limited to 18 languages, which may not cover all multilingual production needs.
- The broad surface area of the platform — transcription, voice agents, LLM gateway — may introduce integration complexity for teams building simple use cases.
Sonix
Pros
- HIPAA-compliant and SOC 2 Type II certified, making it suitable for healthcare, legal, and regulated industries.
- Automated speech-to-text with speaker diarization and automatic timestamps works cleanly according to user reviews.
- Browser-based editor syncs audio and text so clicking a word jumps to that exact point in the recording.
- Supports transcription and translation across 54+ languages within a single workflow.
- Mobile apps on iOS and Android allow field teams to record and auto-sync transcripts.
- API access enables developer integrations and enterprise-level workflows.
- Over six million users signals a proven, stable product with real-world validation.
- Plentiful export formats give flexibility for different downstream use cases.
Cons
- Sonix is a narrow specialist tool with no text-to-speech, voice cloning, music generation, or audio enhancement features.
- Not a generalist platform, so teams needing an all-in-one audio or media tool will need additional software.
- No explicit mention of advanced collaboration features, which may limit larger team workflows.
- Translation quality depends on a neural machine translation layer that may not match human-level accuracy for complex content.
- Smaller user base than major competitors like Otter.ai, which may reflect ecosystem or integration limitations.
- Purely browser and app-based with no indication of robust offline functionality for field teams.
Side by side
| Company | ||
| Founded | 2017 | 2017 |
| HQ | San Francisco, USA | San Francisco, USA |
| AI model | Universal-3.5 Pro (Proprietary) | Proprietary ASR + Neural MT |
| User base | Millions of developers | 6.2M+ |
| Platforms | Web, API (all platforms via SDK) | Web, iOS, Android |
| Languages | 99 (Universal-2), 18 (Universal-3.5 Pro) | 54+ |
| Pricing | ||
| Pricing model | Credit-based | Subscription |
| Free plan | Yes | No |
| Free trial | Yes-unlimited (free tier, no credit card required — up to 185 hours pre-recorded, 333 hours streaming) | Yes — 30 minutes, no credit card required |
| Starting price | $0.15/hr | $10/hr (Pay As You Go) |
| Enterprise | Custom pricing with custom rate limits, enhanced concurrency, and enterprise-grade flexibility | Custom pricing |
| All plans | Free Tier — Free Universal-3.5 Pro — $0.15/hr Universal-3.5 Pro — $0.21/hr Enterprise / Custom — Custom | Pay As You Go — $10/hr usage Core — $25/mo Advanced — $50/mo Pro — $80/mo Enterprise — Custom |
| Positioning | ||
| Best for | Developers and enterprises building voice AI applications, transcription services, and voice agents | Healthcare, legal, media, and research teams needing accurate, secure transcription at scale |
| Differentiator | Native code switching and highly accurate speaker diarization; async speech-to-text trained on 12.5M+ hours of audio | SOC 2 Type II and HIPAA-compliant transcription with 99% accuracy across 54+ languages, purpose-built for regulated industries like healthcare and legal |
| Competitors | Deepgram, OpenAI Whisper, Google Speech-to-Text, Amazon Transcribe, Rev.ai | Otter.ai, Rev.com, Descript, Trint, Happy Scribe |
| Features | ||
| Async Speech to Text | ✓ | — |
| Async Transcription | ✓ | — |
| Code Switching | ✓ | — |
| Multi Language Support | ✓ | — |
| Speaker Diarization | ✓ | — |
| API Access | ✓ | ✓ |
| Audio Enhancement | ✕ | ✕ |
| Batch Processing | ✓ | ✓ |
| Commercial Rights | ✓ | ✓ |
| Languages Supported | ✓ | ✓ |
| Mobile App | ✕ | ✓ |
| Music Generation | ✕ | ✕ |
| Noise Removal | ✕ | ✕ |
| Podcast Editing | ✕ | ✓ |
| Text to Speech | ✕ | ✕ |
| Transcription | ✓ | ✓ |
| Voice Cloning | ✕ | ✕ |
| Voice Styles | ✕ | ✕ |
| Integrations | ||
| Adobe Audition | ✕ | ✕ |
| API Access | ✓ | ✓ |
| Garageband | ✕ | ✕ |
| Key Integrations | AWS Marketplace, GPT (LLM Gateway), Claude (LLM Gateway), Gemini (LLM Gateway), Community LLM Models, Python SDK, REST API, WebSocket Streaming API | Zoom, Microsoft Teams, Google Meet, Webex, Zapier, Adobe Premiere |
| Zapier | — | ✓ |
Section 03
AssemblyAI vs Sonix: common questions
Is AssemblyAI or Sonix cheaper?
AssemblyAI's cheapest paid plan is $0.15/hr and Sonix's is $10/hr (Pay As You Go). Compare what each plan includes below before going on price alone.
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