Speech-to-text APIs · Comparison
AssemblyAI vs Deepgram vs Google Cloud Speech-to-Text vs Speechmatics
4 products compared side by side: what you pay for with each one first, then the five access facts, entry prices, recorded plan limits and the bottom line of each review. The evidence note under the table says how each product was checked.
Side by side
| Metric | AssemblyAI | Deepgram | Google Cloud Speech-to-Text | Speechmatics |
|---|---|---|---|---|
| What you're paying for | Compliance includedA transcription API whose BAA, training opt-out and retention controls are self-serve on paid accounts, with diarized batch audio from $0.17 an hour. | Worth the priceSpeaker-labelled transcripts of pre-recorded audio at $0.0043 a minute with nothing extra to add, plus regional endpoints and a self-hosting path for later. | Built-in reachSpeech recognition inside your Google Cloud account, with IAM, audit logs, a BAA and EU processing, and dynamic batch at $0.003 a minute. | Compliance includedTranscription in 55+ languages where your audio stays out of model training unless you opt in, with EU, US and Australian processing for every account. |
| Overall score | 8.4Best | 6.6 | 7.8 | 8.1 |
| Free option | Free trial | Free trial | Free plan | Free trial |
| Card to start | No card needed | No card needed | Card required | No card needed |
| Getting access | Self-serve | Self-serve | Self-serve | Self-serve |
| Starter priceCheapest paid plan | $0.15/hr | $0.0043/min | $0.003/min | $0.24/hr |
| Pricing model | Usage-based | Usage-based | Usage-based | Usage-based |
| Pricing page | Public prices | Public prices | Public prices | Public prices |
| Billing unit | Per second of pre-recorded audio; streaming by session time, idle included; multichannel per channel | Per second of audio; multichannel billed per channel | Per second of audio, no minimum; each channel billed | Per second, from credits at hourly rates; credit price falls with packs and subscriptions |
| Free credit | $50 at sign-up, no card, does not expire | $200 at sign-up, no card | 60 minutes a month on the V1 API; none on V2 | $100 at sign-up, no card, valid 12 months |
| Streaming rate | Universal-Streaming $0.15/h; Universal-3.6 Pro Realtime $0.45/h | Nova-3 Monolingual $0.0077/min regular; $0.0048/min limited-time promotional | $0.016/min ($0.96/h), the same as batch | Melia 1 $0.40/h; Standard $0.45/h; Enhanced $0.80/h (list) |
| Diarization | Batch +$0.02/h; streaming +$0.12/h (beta in the docs) | Included on pre-recorded audio; streaming +$0.0020/min | No separate price; Chirp 3 diarization in batch only | Included; real-time speaker labels on Enhanced, Standard and Linden, not Melia 1 |
| Languages | 99 on Universal-2; 18 on Universal-3.5 Pro | 45+ (pricing page) | Over 125 (product page) | 55+ (pricing page); 56 for Melia 1 |
| Training on your audio | By default; paid accounts opt out online, free accounts cannot | By default; opt out per request (mip_opt_out=true) | Not without your permission; V1 data logging opt-in gives a lower rate | Only if you opt in (33% off) |
| HIPAA BAA | Signed online at no cost on paid plans | Enterprise, through sales | Covered; accepted in the console per the docs | Sub-BAA through the Trust Center; plan and process not stated |
| EU processing | EU endpoint for batch and streaming, same price as US | EU endpoint with existing keys, no plan limit stated; also Australia and India | Chirp 3 GA in the eu multi-region | EU, US and Australia regions for all customers |
| Self-hosted | Streaming only, $20,000 upfront commitment | Enterprise containers; Amazon SageMaker route with an AWS account | Speech-to-Text On-Prem on GKE, through sales | On-prem containers, virtual appliance and on-device on Enterprise |
| SOC 2 / ISO 27001 | SOC 2 Type 2; ISO 27001:2022 | SOC 2 Type II (report on request); ISO 27001 not stated | SOC 2 Type II and ISO 27001 (Compliance Reports Manager) | SOC 2 Type II (Trust Center, under NDA); ISO/IEC 27001:2022 |
| Console SSO | SAML/OIDC add-on, $199/month per connection | Not documented | SAML through Cloud Identity Free, no listed cost | SAML/OIDC on Enterprise, $280/month add-on |
| Bottom line | From its public pages, AssemblyAI combines the lowest 500-hour price here with compliance controls you switch on yourself: a BAA, a training opt-out and retention as short as an hour. A few add-on prices differ between its pages. | From its public pages, Deepgram pairs low batch rates, diarization included, with a $200 credit and self-hosting. Model improvement is on unless each request opts out, the BAA is Enterprise only, and streaming runs on promotional rates. | From its public pages, Google Cloud Speech-to-Text suits teams inside Google Cloud: no training without permission, a BAA, EU processing and dynamic batch at $0.003 a minute. Features need checking per model, and there is no PII redaction. | From its public pages, Speechmatics has the strictest privacy defaults of the five: no training unless you opt in, 7-day batch retention and real-time audio not stored. Its pricing page leads with discounted rates, and redaction, SSO and on-prem are Enterprise features. |
Evidence: AssemblyAI: facts checked 2026-10-16 from its public sign-up and pricing pages, no completed hands-on run; Deepgram: facts checked 2026-10-16 from its public sign-up and pricing pages, no completed hands-on run; Google Cloud Speech-to-Text: facts checked 2026-10-16 from its public sign-up and pricing pages, no completed hands-on run; Speechmatics: facts checked 2026-10-16 from its public sign-up and pricing pages, no completed hands-on run. Prices in USD as listed, excluding tax. "–" means not recorded.
When to pick each
In the words of each review, with the date its facts were checked.
From our AssemblyAI review
Checked Oct 16, 2026- Pick AssemblyAI when
- You want a BAA signed online, a DPA with the terms, ISO 27001 and a delete API.
- Pick Deepgram when
- You want diarization included in the batch rate, a $200 credit and self-hosted containers for batch as well as streaming.
From our AssemblyAI review
Checked Oct 16, 2026- Pick AssemblyAI when
- You want the lower 500-hour price ($85 against $120 a month, computed) and a BAA you can sign online.
- Pick Speechmatics when
- You want audio kept out of training by default and streaming diarization at no extra cost on Enhanced and Standard.
From our AssemblyAI review
Checked Oct 16, 2026- Pick AssemblyAI when
- You want PII redaction, a $50 credit with no card and every add-on priced per hour.
- Pick Google Cloud Speech-to-Text when
- You already use Google Cloud and want its IAM, audit logs and BAA under your existing account.
From our Deepgram review
Checked Oct 16, 2026- Pick Deepgram when
- You want the largest free credit, diarization included in the batch rate, or a self-hosted option beyond streaming.
- Pick AssemblyAI when
- You want a BAA signed online, a DPA with the terms, ISO 27001, a delete API and a lower 500-hour cost ($85 a month on Universal-2, computed).
From our Deepgram review
Checked Oct 16, 2026- Pick Deepgram when
- You want EU, Australia and India endpoints with one key and a $200 credit the pricing page says has no expiration.
- Pick Speechmatics when
- You want customer audio left out of training by default, batch files deleted after 7 days and streaming diarization included on Enhanced and Standard.
From our Google Cloud Speech-to-Text review
Checked Oct 16, 2026- Pick Google Cloud Speech-to-Text when
- You want training off by default and Google Cloud IAM, audit logs and SSO at no listed cost.
- Pick AssemblyAI when
- You want PII redaction, a $50 credit with no card and a BAA signed online in a speech-only account.
From our Google Cloud Speech-to-Text review
Checked Oct 16, 2026- Pick Google Cloud Speech-to-Text when
- You want dynamic batch pricing and a BAA within your Google Cloud account.
- Pick Speechmatics when
- You want a $100 sign-up credit, a stated 7-day batch retention and a delete-job API.
From our Speechmatics review
Checked Oct 16, 2026- Pick Speechmatics when
- You want audio kept out of training by default and streaming speaker labels at no extra cost.
- Pick AssemblyAI when
- You want a BAA signed online, PII redaction as a per-hour add-on and a lower 500-hour price ($85 a month, computed).
From our Speechmatics review
Checked Oct 16, 2026- Pick Speechmatics when
- You want training off by default, processor terms in the Terms of Service and a stated 7-day retention.
- Pick Deepgram when
- You want a larger credit that the pricing page says has no expiration, and self-hosting through Amazon SageMaker.
From our Speechmatics review
Checked Oct 16, 2026- Pick Speechmatics when
- You want a $100 sign-up credit, a stated 7-day batch retention and a delete-job API without a cloud account.
- Pick Google Cloud Speech-to-Text when
- You already run on Google Cloud and want its IAM, audit logs and a BAA under your existing account.
Entry price
Baseline: each product's cheapest paid plan, per month. Included usage differs, so read the line under each price.
- AssemblyAIUniversal-2, pre-recorded$0.15/hrBilled per second; 99 languages
- Diarization +$0.02/h
- Keyterm prompting included (pricing page)
- PII redaction +$0.08/h
- Word timestamps and confidence included
- DeepgramNova-3 Monolingual, pre-recorded$0.0043/min$0.26/h; Growth $0.0036/min; billed per second
- Speaker diarization and smart formatting included
- Word timestamps and confidence
- Keyterm prompting +$0.0013/min
- Redaction +$0.0020/min
- Google Cloud Speech-to-TextV2 standard recognition$0.016/minFirst 500,000 min a month; then $0.01, $0.008 and $0.004
- Batch, sync and streaming at one price
- Chirp 3 priced at $0.016 on the product page
- Diarization and speech adaptation with no separate price
- SpeechmaticsPro: Melia 1, pre-recorded$0.24/hrPay-as-you-go list rate; $0.16 with the model-training opt-in
- Speaker diarization included
- 56 languages, code-switching
- Word timestamps included
Prices as listed on each pricing page, in USD per month, excluding tax. Observed: AssemblyAI 2026-10-16, Deepgram 2026-10-16, Google Cloud Speech-to-Text 2026-10-16, Speechmatics 2026-10-16.
Which one fits
- If you need to start today without a sales call
- AssemblyAISelf-serve sign-up, no card needed; the highest score of the 4 self-serve products here (8.4/10).
- If you want to try it without entering a card
- AssemblyAIFree trial, no card needed, and the highest score of the 3 that skip the card (8.4/10).
- Highest overall score
- AssemblyAI8.4/10 (Excellent). The review shows the score breakdown and the run behind it.
Picked by fixed rules from the table above, not by hand. How we score