AssemblyAI vs Deepgram
AssemblyAI scores 8.6 to Deepgram's 7.3 among the speech-to-text APIs we rate, and is the better pick for 2 of the 4 kinds of buyer below.
AssemblyAI wins, 8.6 to 7.3
Start with the thing that disqualifies one of these for most people: neither AssemblyAI nor Deepgram has a consumer interface. There is no dashboard where you drop in an MP3 and download a transcript. Both are developer platforms and both require code. If you are building something, the choice comes down to whether you need speech understood or a whole voice agent.
Pick AssemblyAI if the job is understanding speech accurately. Universal-3.5 Pro handles native code-switching across 18 languages at a real-time factor of 0.008x, and speaker diarization is a genuine strength. Pricing is transparent at $0.15/hr. Note it has no text-to-speech or voice cloning at all, so it covers speech in, not speech out.
Pick Deepgram if you are building a voice agent rather than a transcript. Its Voice Agent API puts speech-to-text, text-to-speech and LLM orchestration behind one low-latency endpoint, which removes a lot of wiring. Nova-3 covers 45+ languages, and self-hosting is available if the audio cannot leave your infrastructure.
Best for
Who each one suits, decided on the criteria that matter to that buyer and the checked facts where the two differ.
- Languages it transcribes: 99 languages against 57 languages
- Time codes per word: AssemblyAI yes, Deepgram does not say
- Apps it connects to: 1 integration against 0 integrations
- Cheapest pre-recorded transcription, per hour: $0.15 against $0.258
- Ways to reach support: AssemblyAI 4 support channels, Deepgram 3 support channels
How they score
Both are scored the same way, against the other speech-to-text APIs we rate, from facts on each vendor's own pages. AssemblyAI leads on 2 of 4 criteria.
Where they differ
Every point where the two vendors' published facts disagree, with a link to where each fact was read. "Not published" means the vendor does not say either way.
Published by only one of them
Where they match (4)
Pricing, plan by plan
Every plan each vendor publishes, monthly and yearly where both are offered.
AssemblyAI
Deepgram
For everything else about each tool, read the full AssemblyAI review and Deepgram review.
The deciding question
Ask what happens after the words are recognised.
If the answer is that your application does something with the text, AssemblyAI is the more focused tool and its accuracy work is where the effort has gone. If the answer is that something has to speak back, Deepgram already contains that half and you would otherwise be integrating a second vendor.
Cost is not directly comparable
AssemblyAI publishes $0.15/hr. Deepgram leads with $200 in free credit and prices per usage after that. The free credit is generous for prototyping, but it means you cannot compare the two on a price sheet — you have to run your actual audio volume through both calculators.
Both carry the same warning
Complexity is growing on both sides. Deepgram's expansion into TTS, Voice Agent and LLM hooks adds surface area on top of the core transcription product, and AssemblyAI has grown well past transcription into audio intelligence. If all you need is accurate text from audio, you are buying more platform than the job requires from either of them.
If you are not a developer
Neither of these is for you, and that is not a criticism of either. Look at a tool with an actual upload button instead.
AssemblyAI vs Deepgram: common questions
Can I use either without writing code?
No. Neither has a consumer-facing dashboard, mobile app or desktop editor. Both are API-first developer platforms, and that is the first thing to check before comparing anything else about them.
Which handles multiple languages in one recording?
AssemblyAI is built for it. Native code-switching across 18 languages is one of its headline capabilities. Deepgram's Nova-3 covers more languages overall at 45+, but switching mid-recording is AssemblyAI's specialism.
Does either do text-to-speech?
Deepgram does, as part of its Voice Agent API. AssemblyAI does not offer text-to-speech, voice cloning or music generation at all, which limits it strictly to speech input and understanding.
