AssemblyAI vs Deepgram
Side-by-side comparison of features, pricing, and ratings
At a glance
| Dimension | AssemblyAI | Deepgram |
|---|---|---|
| Pricing | Freemium (100 hrs free trial), Pay-as-you-go $0.21/hr (U-3.5 Pro), $0.15/hr (U-2), Voice Agent $0.30/hr | Freemium ($200 credit free tier), Pay-as-you-go from $0.0049/min (real-time STT), $0.017/min (batch STT), TTS $0.0013/char |
| Best For | High-accuracy batch transcription, voice agents with LLM orchestration, speech understanding | Real-time voice agents, contact centers, low-latency conversational AI |
| Languages | 18 languages (U-3.5 Pro highest accuracy); 99 languages (U-2) | 10 languages (Flux Multilingual conversational); 50+ for profanity filtering |
| Key Differentiator | Context Carryover in real-time, LLM Gateway, Speech Understanding (chapters, summaries) | Unified Voice Agent API (STT+TTS+LLM) & self-hosting option |
| Integrations | Pipecat, ElevenLabs, Zoom, Siro, GPT/Claude/Gemini, LiveKit | Amazon Connect, Twilio, Asterisk, Python/Node/Go/.NET/Java SDKs |
| Free Tier | 100 hours free (one-time), then pay-as-you-go | $200 credit (one-time) plus limited free usage (e.g., 60 min batch/month) |
If your priority is low-latency real-time STT with a unified Voice Agent API and you value TTS integration or self-hosting, Deepgram is the stronger choice. For developers who need high-accuracy batch transcription with rich speech understanding (chapters, summaries, sentiment) and an LLM gateway, AssemblyAI pulls ahead. Both are excellent, but pick based on workflow: live vs. pre-recorded.
Who should pick which
- Solo founder building a real-time voice agent for customer supportPick: Deepgram
Deepgram's unified Voice Agent API and low-latency STT ($0.0049/min) reduce integration cost and runtime expense, and the free $200 credit helps prototype quickly.
- Developer creating a podcast transcription service with chapters and summariesPick: AssemblyAI
AssemblyAI's Universal-3.5 Pro delivers high-accuracy batch transcription and built-in Speech Understanding (chapters, summaries) without extra cost.
- Enterprise needing on-premises deployment for compliancePick: Deepgram
Deepgram offers self-hosting options, while AssemblyAI requires cloud API (Self-hosted Voice AI Cloud is still cloud-dependent).
- Healthcare app requiring medical transcription with domain-specific accuracyPick: AssemblyAI
AssemblyAI's Keyterms Prompting and high-accuracy models improve medical terminology, and the LLM Gateway can route to HIPAA-compliant LLMs.
- Multilingual app needing real-time transcription in 10+ languagesPick: Deepgram
Deepgram's Flux Multilingual covers 10 languages with conversational turn detection, ideal for global voice agents.
Frequently Asked Questions
AssemblyAI vs Deepgram: which should you choose?
If your priority is low-latency real-time STT with a unified Voice Agent API and you value TTS integration or self-hosting, Deepgram is the stronger choice. For developers who need high-accuracy batch transcription with rich speech understanding (chapters, summaries, sentiment) and an LLM gateway, AssemblyAI pulls ahead. Both are excellent, but pick based on workflow: live vs. pre-recorded.
Which service has lower latency for real-time STT?
Deepgram is known for sub-300ms latency with its Nova-3 and Flux models, making it ideal for real-time voice agents. AssemblyAI's real-time model (U-3.5 Pro Realtime) also offers low latency but benchmarks suggest Deepgram edges ahead.
Can I use Deepgram's Voice Agent API without TTS?
Yes, the Voice Agent API can combine STT and LLM only; TTS is optional. You can also use Deepgram's STT standalone.
Does AssemblyAI offer TTS?
AssemblyAI focuses on STT and voice agent API; TTS is not natively included. It integrates with ElevenLabs for TTS via partnerships.
Which service supports more languages?
AssemblyAI's Universal-2 supports 99 languages, but Universal-3.5 Pro (highest accuracy) supports 18. Deepgram's Nova-3 Multilingual supports 10 languages. For broad coverage, AssemblyAI wins.
Can I self-host Deepgram?
Yes, Deepgram offers a self-hosted deployment option for enterprises. AssemblyAI's 'Self-hosted Voice AI Cloud' still requires cloud connectivity.
Which has better integration for contact centers?
Deepgram has native integrations with Amazon Connect and Twilio, making it stronger for contact center use cases.
Does AssemblyAI's free tier expire?
AssemblyAI offers 100 hours of free transcription (one-time). After that, you pay as you go. Deepgram's free tier includes a $200 credit that usually lasts longer for small workloads.
Which is better for voice agent call analytics?
AssemblyAI's LLM Gateway and Speech Understanding (sentiment, chapters, summaries) provide richer analytics out of the box. Deepgram's Audio Intelligence adds emotion and topic detection but may require additional setup.
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Last reviewed: May 12, 2026