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It's a split decision.
Choose AssemblyAI if you need speech APIs with a clearly listed entry rate: selected transcription options start at $0.15/hour, though add-ons can raise the bill. Choose Deepgram if real-time voice agents are the priority and you want $200 in non-expiring credit to start; its paid usage rates are not published here, and Growth begins at $4,000 prepaid annually. Neither is a clean price comparison: scopes and billing units differ.
01Side by side
| AssemblyAI | Deepgram | |
|---|---|---|
| Starting price | $0.15/hour for listed transcription options | Usage-based; starting rate not published |
| Free plan | Free plan listed; terms not detailed | $200 credit; no expiration or card required |
| Best for | Transcription and speech understanding | Real-time voice apps and agents |
| Core strength | Transcription, summaries, sentiment, and entities | Real-time speech, TTS, and voice agents |
| Learning curve | Not published | Not published |
| Integrations/data | Self-host inference in VPC or on-premises | Self-hosting available on Enterprise |
| Team/seat costs | Seat costs not published | Seat costs not published |
| Support | Support details not published | Named account team on Enterprise |
AssemblyAI Choose AssemblyAI if
- Choose AssemblyAI if you want listed transcription rates from $0.15/hour.
- Choose AssemblyAI if summaries, sentiment, or entity extraction matter.
- Choose AssemblyAI if you need self-hosted inference in your VPC or on-premises.
Deepgram Choose Deepgram if
- Choose Deepgram if real-time voice agents are your main use case.
- Choose Deepgram if $200 in non-expiring credit helps you evaluate usage.
- Choose Deepgram if you need an Enterprise named account team or self-hosting.
02Pricing compared
AssemblyAI lists selected speech-to-text options from $0.15 per hour: Pre-recorded Universal-2 and two realtime streaming options. Other listed rates include $0.21/hour for Pre-recorded Universal-3.5 Pro, $0.45/hour for Realtime Universal-3.6 Pro, and $0.30/hour for the Sync API. These are usage rates, not monthly plans. Add-ons can raise the bill: for example, diarization is $0.02/hour on Pre-recorded Universal-2 and $0.12/hour on Realtime Universal-3.6 Pro.
Deepgram’s Pay as you go plan has no minimum and includes $200 in non-expiring credit, but its usage rates are not published here. Growth starts at $4,000 prepaid annually, with overages billed at Growth rates plus 10%. The units and plan structures differ, so compare your expected usage—not just the headline rates.
03Features and depth
Both platforms cover speech-to-text and text-to-speech, and both target real-time voice applications. AssemblyAI also lists speech understanding features such as summaries, sentiment, and entity detection, plus speaker labels for prerecorded transcription. Its models separate recorded audio, live streams, and short clips into different APIs. Self-hosted inference is available in a customer VPC or on-premises.
Deepgram’s platform includes speech recognition, speech generation, voice agents, and audio intelligence. Its product details emphasize real-time processing, including Flux TTS for real-time voice experiences. The Enterprise plan lists custom model training and self-hosted deployment. Deepgram also lists a developer playground.
The pricing details expose some feature costs more clearly for AssemblyAI: its listed add-ons include diarization, prompting, Medical Mode, and PII redaction, with rates varying by model. Deepgram lists per-minute charges for redaction, keyterm prompting, entity detection, and diarization. Check which model and add-ons your use case needs before comparing totals.
04Ease of use and learning curve
Neither product is a simple like-for-like switch: both are APIs for adding speech capabilities to a product, so implementation depends on your audio workflow and the features you need. AssemblyAI separates prerecorded, realtime, and short-clip processing into different APIs; that makes the choice of endpoint part of setup. Deepgram lists a developer playground for exploring its platform, which may help teams evaluate the available tools before integrating them.
For a first cost check, AssemblyAI’s listed hourly rates are easier to map to audio volume, while Deepgram’s usage rates are not published here. Deepgram does publish its concurrency limits by plan: 150 streaming speech-to-text connections on Pay as you go and 225 on Growth. Validate model fit and expected traffic before committing.
Questions people ask
Which is cheaper, AssemblyAI or Deepgram?
There is no reliable across-the-board winner from the published figures here. AssemblyAI lists selected transcription rates from $0.15 per hour, while Deepgram’s Pay as you go usage rates are not published. Deepgram Growth starts at $4,000 prepaid annually. Compare the specific models, add-ons, and expected volume.
Which is better for real-time voice agents?
Both offer tools for real-time voice applications. AssemblyAI lists Realtime Universal-3.6 Pro at $0.45 per hour and streaming options at $0.15 per hour. Deepgram highlights voice agents and real-time speech processing, but its Pay as you go rates are not listed here. Evaluate both against your own audio and requirements.
Do AssemblyAI and Deepgram have free plans?
Both list a free way to start, but the terms differ. Deepgram Pay as you go includes $200 in credit with no expiration and requires no credit card to start. AssemblyAI lists a free plan, but the published pricing details do not specify its allowance or limits.
Can I self-host either platform?
AssemblyAI says its inference can run in your own VPC or on-premises. Deepgram lists self-hosted deployment on its Enterprise plan, alongside custom pricing. The published details do not specify deployment requirements or costs, so ask each vendor for terms that match your security and infrastructure needs.