AssemblyAI vs Sonix Comparison 2026
AssemblyAI is a speech to text API: audio in, a transcript out, for $0.15 an hour after 185 free hours, with no screen anywhere in the product. Sonix is the opposite shape: an editor where the text lines up against the audio so a person can fix mistakes by clicking a word, from $10 an hour pay as you go or $25 a month for a bundle of hours. One assumes a person will sit and correct the transcript by hand. The other assumes the output only ever gets read by more code.
At a glance
- Only AssemblyAI has a free tier.
Side by side
AssemblyAI | Sonix | |
|---|---|---|
| Starting price | Not listed | From $10 |
| Pricing model (they differ) | Free plan, paid tiers | Free trial, then paid |
| Free tier (they differ) | Yes | No |
| Billing | Usage-based | Usage-based |
| Free trial | Not stated | Not stated |
| API | Yes |
AssemblyAI
Speech to text you call as an API
AssemblyAI is a speech to text API rather than an app: you send audio and get back a transcript, with speaker labels and summarisation available on the same call. Both pre-recorded and live streaming are covered, and the free tier is generous enough to build something real before paying anything. It is bought by people writing software, not by people who want a transcript this afternoon.
Our note
At fifteen cents an hour the price is not the thing to agonise over, so pick on accuracy for your audio and on whether you want speaker labels in the same call. Deepgram is the direct comparison and the two trade places depending on the recording.
Sonix
Transcription you can pay for by the hour
Sonix will bill by the hour rather than by the month, which is the right shape for somebody who transcribes a batch of interviews twice a year and nothing in between. Accuracy across its 54 languages is good and the editor lines the text up against the audio. Subscribers get storage and an AI workspace that the hourly rate does not include.
Why people weigh these two
- Sonix instead of AssemblyAI
- Transcription you pay for by the hour, bought as a service with a free trial instead of an API with a build-first free tier.
- AssemblyAI instead of Sonix
- AssemblyAI is an API to call from your own code rather than an app to log into, with a free tier, for a developer building transcription into a product.
Which one should you pick
AssemblyAI is for a team building a product on top of transcripts: a captioning feature, a search tool, a pipeline running across thousands of files with nobody opening any of them. The free tier holds 185 hours, so the whole thing gets prototyped before it costs anything, then $0.15 an hour after that with no interface to license.
Sonix is for somebody who transcribes in bursts, like an interview series or a research project twice a year, and wants to sit in an editor and fix the output by clicking a word. Pay As You Go is $10 an hour with no monthly commitment, or Core at $25 a month covers five hours plus 25GB of storage for regular use. Anybody transcribing every week outgrows the hourly plan fast and should price it against Core rather than the per-hour rate.
Common questions
- Does AssemblyAI have an editor like Sonix?
- No. AssemblyAI only returns transcript data over an API, so whatever screen a user sees has to be built by whoever calls it. Sonix ships the editor itself, with the text lined up against the audio so a click on a word jumps the recording there.
- Which is cheaper for occasional use?
- Neither charges a subscription for one-off jobs. AssemblyAI is $0.15 an hour with 185 free hours first, so a handful of files can cost nothing. Sonix Pay As You Go is $10 an hour, with a 30-minute trial and no free tier beyond it.
- Can AssemblyAI be used without writing code?
- No, it is only an API, so a developer has to be involved somewhere in the chain. Sonix needs none: upload a file, correct it in the editor, export it.
- Is there a free way to try either one?
- Yes, both. AssemblyAI's free tier holds 185 hours of pre-recorded transcription before billing starts. Sonix gives a 30-minute trial, enough to check accuracy on your own audio before paying anything.
Ratings are the average of reviews readers left. The facts are stated by each tool’s own listing and are not verified by CloutStack. How we make money.