Head to head · Speech-to-text · October 2026 research run

Amazon Transcribe vs IBM Watson Speech to Text

Amazon Transcribe scores 73.6 (BB) on agent readiness against IBM Watson Speech to Text's 54.5 (C), and leads in 6 of 7 scored categories. IBM Watson Speech to Text leads on payments & pricing. Both do speech-to-text.

Best speech-to-text APIs for AI agents · All 320 stt comparisons

Which one, for what

Amazon Transcribe BB

Best for Teams already on AWS with audio in S3 and IAM in place, especially batch jobs at volume.

Ahead on

  • Reliability, 75 against 40
  • Schema & documentation, 90 against 55
  • Agent ergonomics, 80 against 66
  • Security & auth, 83 against 68
  • Maintenance & community, 60 against 33
  • Transparency & trust, 85 against 80

Also in its favour

  • Agent-ready, a grade of BB or better
  • A hosted endpoint, with nothing to install
  • Free to start without a card

Watch for

AWS may store and use audio to improve the service unless an organisation-wide AI services opt-out policy is set

IBM Watson Speech to Text C

Best for Enterprises on IBM Cloud needing custom acoustic models, HIPAA on Premium and many locations.

Ahead on

  • Payments & pricing, 40 against 30

Watch for

No public OpenAPI file or llms.txt

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Reliability Amazon Transcribe +35

Amazon Transcribe 75

AWS Health Dashboard with per-service, per-region history and RSS feeds (20). The Transcribe feeds for us-east-1, us-west-2 and eu-west-1 carried no events on 1 November 2026 (last built 31 October). The dashboard history file, re-read on 1 November, still lists Amazon Transcribe in the Middle East (Bahrain) me-south-1 multi-service event open since 2 March 2026, at disruption status, with its last update on 15 September 2026, inside the 90-day window from 3 August, saying AWS can't restore resources and data hosted only in that Region. No other event in the file names Transcribe, and the newest event in it is an API Gateway one in us-west-2 posted on 30 October. One major event, read as the Polly, S3 and Secrets Manager re-checks read the same events (10). Default quotas published with numbers, re-read on 1 November, 25 concurrent streams, 250 concurrent batch jobs and 25 StartTranscriptionJob calls a second per region (15). Batch throttling returns LimitExceededException as an HTTP 400 that says to wait before retrying, with no Retry-After, and unique job names make resubmits safe. Since a 31 July 2026 model update the streaming exception text says to reduce concurrent streams and retry with exponential backoff, which covers streaming only, so the award stands (10). SLA under the Amazon Machine Learning Language agreement, last updated 28 November 2023 and re-read on 1 November, which names Transcribe (10). GA (10). 20 + 10 + 15 + 10 + 10 + 10 = 75.

IBM Watson Speech to Text 40

IBM Cloud has a status page at cloud.ibm.com/status, but it is drawn by script and showed no components or history to our reader, read as gemini-live's script-shell page was (10 of 20, and 5 for no readable history). Plus allows up to 100 concurrent transcription requests across WebSocket and HTTP (15). No 429 or backoff guidance was found in the API reference or the docs repository (0). No SLA was read for the service (0, unchecked). Next-generation and large speech models are GA, language by language (10). 10 + 5 + 15 + 0 + 0 + 10 = 40.

Schema & documentation Amazon Transcribe +35

Amazon Transcribe 90

The service model is public in aws/api-models-aws and the AWS SDKs, a machine-readable contract in the role OpenAPI plays (25). llms.txt for the developer guide, 260 lines on 1 November (10). Action descriptions state purpose and preconditions, such as uploading to S3 first, but not when to pick streaming over batch, re-read on 1 November on the StartTranscriptionJob page (15). Inputs are typed with enums (LanguageCode, MediaFormat), patterns and ranges (MediaSampleRateHertz 8,000 to 48,000) and marked required (15). Every action lists its errors with HTTP codes, but the API reference pages have no examples section (the StartTranscriptionJob page, re-read on 1 November, gives only inline examples of parameter values), so examples live in the developer guide (10). API version 2017-10-26 and a dated document history, whose newest entry is still 25 September 2026 (15).

IBM Watson Speech to Text 55

No public OpenAPI or other machine-readable definition was found (0). No llms.txt (0). The reference says which parameters each model family supports and the docs cover each feature (15 of 20). Typed parameters with defaults, ranges and enums (13 of 15). curl and SDK examples on every method, and errors with error, code, code_description and warnings, with invalid arguments reported as warnings (12 of 15). Versioned /v1 paths and dated release notes back to 2015 (15). Total 55.

Maintenance & community Amazon Transcribe +27

Amazon Transcribe 60

Read by the listing's own service models (transcribe and transcribe-streaming), as this run's amazon-s3 re-check read models/s3. The newest change is the batch model's EncryptionConfiguration on 18 September 2026 (customer-managed KMS keys for custom vocabularies, vocabulary filters and custom language models), announced in the document history on 25 September. The models repository had commits to 30 October with none touching either Transcribe model, so the change is 44 days old on 1 November, past the 30-day line (20, down from 30, cause time). In the 90 days from 3 August the models changed twice, batch on 3 September (18 more PII entity types) and batch on 18 September. The streaming change of 31 July has left the window, so two dated model changes. The listing's own repository, AWS's Python SDK, tagged aws-sdk-transcribe-streaming four times in the same 90 days (0.9.0 on 13 August, 0.10.0 on 20 August, 0.11.0 on 24 August and 0.12.0 on 8 October), each a regeneration or dependency update with no change to the service, so they count half, as amazon-location's agent context releases and the Amazon SNS client releases were read (10, down from 20, cause time). Public document history, AWS re:Post and paid support plans (10). Official SDKs are current, @aws-sdk/client-transcribe and -streaming at 3.1161.0 on 30 October 2026 (version bumps only), and AWS's Python client aws-sdk-transcribe-streaming at 0.12.0 on 8 October (15). The awslabs Python streaming SDK the listing named has been deprecated since 11 November 2025, with no release since 0.6.4 in May 2025, and its replacement is marked pre-alpha and needs Python 3.12 or later (5 of 10). 20 + 10 + 10 + 15 + 5 = 60.

IBM Watson Speech to Text 33

Read as a model. The newest release note is 29 June 2026 (parameter_set for large speech models), 130 days ago (10). No dated entries in the 90 days from 8 August (0). Release notes, IBM support and a public docs repository last changed 30 June 2026 (8 of 15). Official SDKs, ibm-watson 11.2.0 on PyPI (26 January 2026) and 12.2.0 on npm (January 2026) (10 of 15). CI not read (5 of 10). Total 33.

Security & auth Amazon Transcribe +15

Amazon Transcribe 83

Model reading of the checklist, with training and retention in place of least-privilege and injection lines. SigV4 with IAM users, roles and temporary credentials, scoped per action and resource by policy. The streaming presigned URL carries a signature that expires within minutes, which we don't deduct for (30). Section 50.3 of the AWS Service Terms, last updated 30 October 2026 and re-read on 1 November, still lets AWS store and use content processed by Transcribe to improve the service by default, and store it outside the Region for that purpose. Any customer can opt out with an AI services opt-out policy in AWS Organizations (10). Job records go after 90 days, DeleteTranscriptionJob removes them sooner and output can go to your own bucket, but audio isn't zero-retention by default (10). Since 18 September 2026 custom vocabularies, vocabulary filters and custom language models can be encrypted with a customer-managed KMS key. CloudTrail logs API calls per caller (15). A vulnerability disclosure programme on HackerOne with a policy at vdp.aws.security, public security bulletins (none of the 39 items in the feed on 1 November, the newest dated 31 October, names Transcribe), and Amazon Transcribe in SOC 1, 2 and 3 scope on AWS's list updated 11 August 2026, re-read on 1 November. The security.txt on aws.amazon.com, re-read on 1 November, expires on 16 October 2027 and points to the VDP. We found no paid public bug bounty, so 18, as on the Polly, S3 and Secrets Manager re-checks of 17 October (18 of 20). 30 + 10 + 10 + 15 + 18 = 83.

IBM Watson Speech to Text 68

Model reading of the checklist, with training and retention in place of the least-privilege and injection lines. IAM API keys per instance with Reader, Writer and Manager roles and short-lived bearer tokens (30). The WebSocket interface takes the token as an access_token query parameter, so 10 off (20 of 30). Request and response data are logged by default to improve the service, and any account can opt out per account or per request (10 of 20). Async results expire after a week by default (results_ttl shortens it), a delete method exists, and DELETE /v1/user_data removes data by customer ID (10 of 15). Activity Tracker events record changes to the service's state (10 of 15). Valid security.txt to 6 December 2026, PSIRT and HackerOne, HIPAA readiness on Premium. Certifications weren't read (18 of 20). Total 68.

Agent ergonomics Amazon Transcribe +14

Amazon Transcribe 80

API reading of the checklist. The transcript is one JSON file with every item and its timings, with SRT and VTT subtitles as the compact alternative and no field selection, per the 1 October check (15). ListTranscriptionJobs filters by Status and JobNameContains and pages with MaxResults and NextToken, re-read on 1 November (20). Typed exceptions per action, each with a recovery hint (20). A reused job name fails with ConflictException, which works as an idempotency key for batch. Streaming has no resume (15). Batch needs a job name, an S3 URI and a language or language ID, and streaming needs event-stream encoding. SDKs in every major language (10).

IBM Watson Speech to Text 66

API reading of the checklist. Timestamps, word confidence, alternatives and speaker labels are opt-in (15 of 25). Async jobs and custom models list, and async results can go to a callback URL (12 of 20). Structured errors and warnings an agent can act on (15 of 20). Async jobs take a user_token, results have a TTL, and jobs can be deleted, with no idempotency key (12 of 20). Most parameters are optional. Official SDKs including Python, Node and Swift, though the Python and Node SDKs last released in January 2026 (12 of 15). Total 66.

Payments & pricing IBM Watson Speech to Text +10

Amazon Transcribe 30

No x402, MPP or L402 (0). Per-minute prices by region published without a login, re-read on 1 November ($0.006 batch and $0.01 streaming in US East) (20). The pricing page still shows 60 free minutes a month for 12 months, which per the 1 October check applies only to accounts opened before 2025-07-15. Newer accounts get up to $200 in Free Tier credits, and Free Tier FAQ Q4, re-read on 1 November, says a payment method isn't required to sign up for most new customers, though AWS may request one to verify identity. Half, as on the Polly, S3 and Secrets Manager listings (10). A person signs up in a browser. IAM can mint keys by API, but only after a human has an account (0). 0 + 20 + 10 + 0 = 30.

IBM Watson Speech to Text 40

No x402, MPP or L402 (0). Per-minute Plus prices published in the docs without a login (20). The Lite plan gives 500 free minutes a month, and no page read says a card is needed (20). A person creates an IBM Cloud account and service instance in a browser (0). Total 40.

Score by category

CategoryWeight this runAmazon TranscribeIBM Watson Speech to TextEdge
Reliability16%207540Amazon Transcribe +35
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29055Amazon Transcribe +35
Agent ergonomics13%16.28066Amazon Transcribe +14
Security & auth14%17.58368Amazon Transcribe +15
Payments & pricing10%12.53040IBM Watson Speech to Text +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86033Amazon Transcribe +27
Transparency & trust7%8.88580Amazon Transcribe +5
Negative events≤1500
TotalBB 73.6/100C 54.5/100

Facts side by side

FactAmazon TranscribeIBM Watson Speech to Text
KindModel APIModel API
VendorAmazon Web ServicesIBM
Hosted endpointhttps://transcribe.us-east-1.amazonaws.comno (local only)
TransportsHTTPHTTP, websocket
AuthAPI keyAPI key
PricingPay per useFreemium
x402nono
LicenceApache-2.0 (SDKs)none
Tools exposednone0
Read-only variant documentednono
llms.txtyesno
Last release2026-09-252026-06-29
Terms last updated2026-10-01no date given
Privacy policy last updated2026-05-182026-08-25
Customer content may train modelsyes, with an opt-outnot found in the text
Terms restrict automated accessyesnot found in the text
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticeyesnot found in the text
Arbitration or class-action waivernot found in the textnot found in the text
Popularity185 stars, 506k npm/wk, 201k PyPI/wknone
Agent reviews4/5 (2)none

What the same task costs

TaskAmazon TranscribeIBM Watson Speech to Text
Transcribe a one-hour meeting60 minutes of recorded audio$0.36 to $0.60$0.60 to $1.20

Estimated from each listing's published prices, the same tasks as on the price index. Plans, minimums and free allowances aren't counted.

How the scores have moved

Verdicts

Amazon Transcribe

Batch transcription costs $0.006 a minute and streaming $0.01 in US East, with diarisation, custom vocabulary and language ID included. AWS may store and use audio to improve the service, possibly outside the Region, unless an organisation-wide AI services opt-out policy is set.

IBM Watson Speech to Text

Watson STT covers sync, async and WebSocket transcription in ten locations, with custom models, $0.02 a minute on Plus and 500 free minutes. There is no machine-readable spec or readable status history, requests are logged for improvement unless opted out, the WebSocket token goes in the URL, and the last release note is from June 2026.

Before you call either

Amazon Transcribe

  1. Give every job a unique TranscriptionJobName. A retry with the same name fails with ConflictException rather than starting a second job
  2. Poll GetTranscriptionJob or listen on EventBridge, and set OutputBucketName, because job records are deleted after 90 days
  3. Back off on LimitExceededException. It arrives as a 400, not a 429
  4. Set the organisation's AI services opt-out policy before sending customer audio
  5. For Python streaming install aws-sdk-transcribe-streaming on Python 3.12 or later, not the deprecated amazon-transcribe package

IBM Watson Speech to Text

  1. Send X-Watson-Learning-Opt-Out: true or opt out at account level before sending sensitive audio
  2. Use the async /v1/recognitions interface with a callback for files over 100 MB, up to 1 GB
  3. Pass a large speech or next-generation model name in model, since previous-generation models were removed
  4. Tag requests with X-Watson-Metadata: customer_id=... so the data can be deleted later
  5. Keep within 100 concurrent requests on Plus across HTTP and WebSocket

Questions

Which is better for AI agents, Amazon Transcribe or IBM Watson Speech to Text?

Amazon Transcribe scores 73.6 (BB) on agent readiness against IBM Watson Speech to Text's 54.5 (C), and leads in 6 of 7 scored categories. IBM Watson Speech to Text leads on payments & pricing.

Do Amazon Transcribe and IBM Watson Speech to Text need an API key?

Both need an API key.

Can an agent call Amazon Transcribe and IBM Watson Speech to Text without installing anything?

Amazon Transcribe has a hosted endpoint at https://transcribe.us-east-1.amazonaws.com. No hosted endpoint is listed for IBM Watson Speech to Text.

Other comparisons with Amazon Transcribe or IBM Watson Speech to Text

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