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

Gladia Speech-to-Text API + MCP vs IBM Watson Speech to Text

Gladia Speech-to-Text API + MCP scores 69.8 (B) on agent readiness against IBM Watson Speech to Text's 54.5 (C), and leads in 4 of 7 scored categories. IBM Watson Speech to Text leads on transparency & trust. Both do speech-to-text.

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

Which one, for what

Gladia Speech-to-Text API + MCP B

Best for Multilingual meetings and calls where live and async transcription in 100+ languages is needed, and for teams who want an MCP server.

Ahead on

  • Reliability, 70 against 40
  • Schema & documentation, 95 against 55
  • Agent ergonomics, 75 against 66
  • Maintenance & community, 70 against 33

Also in its favour

  • A hosted endpoint, with nothing to install
  • Runs on your own machine
  • Free to start without a card

Watch for

Self-serve audio is used for model training by default unless the account opts out

IBM Watson Speech to Text C

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

Ahead on

  • Transparency & trust, 80 against 65

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.

Schema & documentation Gladia Speech-to-Text API + MCP +40

Gladia Speech-to-Text API + MCP 95

OpenAPI file at api.gladia.io/openapi.json (25). llms.txt (10). Reference pages state purpose per endpoint and the model page says to use solaria-3 only for async English, French, German, Spanish or Italian (15). Typed bodies with enums and required fields, audio_url the only required input for pre-recorded (15). Examples per endpoint and documented error codes (15). Versioned /v2 paths and a dated changelog (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 Gladia Speech-to-Text API + MCP +37

Gladia Speech-to-Text API + MCP 70

Read as a model, for deprecation notice and model churn rather than release counts, on the lines deepgram-stt was settled on in this run. SDK 2.2.0 on 13 October 2026, three fixes among them limiting list pagination to the configured API, 19 days before 1 November (30). 2.2.1 on 23 October only raises the Python certifi floor to distrust a compromised certificate authority and is a version bump with no code changes for JavaScript, so as a dependency-only release it counts half and doesn't set this line, as azure-translator's was read. In the 90 days from 3 August, changelog entries on 8, 9 and 14 September, SDK 2.1.0 (18 and 21 September), 2.2.0 and 2.2.1 (at half), and the MCP server 0.1.0 and 0.1.1 on 24 September (10). The /v2/transcription endpoints are marked deprecated in favour of /v2/pre-recorded with no removal date, structured data extraction has gone from the OpenAPI file without a changelog entry, and no deprecation policy was found (0 of 10). Public changelog, help centre and Discord (10 of 15). SDK and MCP repository issues couldn't be read, since github.com refuses our reader, so absent (0 of 10). Official JavaScript and Python SDKs current at 2.2.1 (15). The SDK repository has CI, release and OpenAPI type-update workflows, results not seen (5 of 10). 30 + 10 + 0 + 10 + 0 + 15 + 5 = 70.

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.

Reliability Gladia Speech-to-Text API + MCP +30

Gladia Speech-to-Text API + MCP 70

incident.io status page with per-component uptime bars and incident pages, and an RSS feed read on 1 November (20). One major incident in the 90 days from 3 August, a global Pre-Recorded and Real-Time incident on 23 September 2026 from 07:05 to 08:10 caused by a provider network fault, as read on 1 October. The rest are partial and read as minor, a 20-minute full outage and a timeouts incident on 22 September, slower processing on the afternoon of 23 September, and Europe-only degradations on 2, 10, 14 to 15 (elevated errors and timeouts in Europe from 09:07 on 14 September to 13:58 on 15 September), 21, 22 and 28 September and on 3, 4 and 7 October (Pre-Recorded v2 in Europe) (10). Concurrency limits published with numbers, 25 parallel async jobs plus 300 queued and 30 live sessions on paid plans, 3 and 1 on free (15). The docs say a 429 means the concurrency limit, but we found no backoff guidance or Retry-After (5). The pricing page's plan comparison, read on 1 November, lists a 99.9% uptime SLA for Enterprise (10). solaria-1 and solaria-3 are GA (10). 20 + 10 + 15 + 5 + 10 + 10 = 70.

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.

Transparency & trust IBM Watson Speech to Text +15

Gladia Speech-to-Text API + MCP 65

Closed service with an MIT SDK and MCP server and separate terms for Gladia SAS and Gladia Inc. (15). The statements disagree. The security page gives a 12-month default retention with custom policies for customers and says only Free plan data trains models, while the retention page gives 1 year on free, 3 weeks on paid and zero retention only on Enterprise, and the pricing page says Self-serve is opted in to training by default. ISO 27001 is described as in progress (15). Breaking changes are flagged with dates in the changelog, such as SDK 2.0.0 and the move to credit billing on 3 July 2026 with a 6 to 20 July rollout, but no deprecation policy was found (10). Hosting with a French provider is stated, and no sub-processor list was found (10).

IBM Watson Speech to Text 80

Closed service under the IBM Cloud terms (15). The data security page states default logging for improvement with an opt-out, async retention, GDPR deletion by customer ID and plan-level separation, and they agree with each other. The DPA wasn't read (20 of 30). Previous-generation models carried a dated deprecation of 15 March 2022 and removal on 31 July 2023, and release notes say changes are compatible unless noted (18 of 20). Ten locations are named, with sub-processors not read (12 of 20). Total 65.

Agent ergonomics Gladia Speech-to-Text API + MCP +9

Gladia Speech-to-Text API + MCP 75

API reading of the checklist. Add-ons such as summaries, NER and translation are opt-in, so a plain request stays small, but there's no field selection (15). Pre-recorded jobs list with offset, limit and filters (20). Documented error codes, with a 429 for concurrency (15). No idempotency key. The docs warn that a job is already queued once the 200 or transcription.created webhook arrives, which is safe-retry guidance of a sort (10). One required parameter and official SDKs in JavaScript and Python (15). The official MCP server adds 8 tools for async jobs, which this API reading doesn't score.

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.

Score by category

CategoryWeight this runGladia Speech-to-Text API + MCPIBM Watson Speech to TextEdge
Reliability16%207040Gladia Speech-to-Text API + MCP +30
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29555Gladia Speech-to-Text API + MCP +40
Agent ergonomics13%16.27566Gladia Speech-to-Text API + MCP +9
Security & auth14%17.56568IBM Watson Speech to Text +3
Payments & pricing10%12.54040even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87033Gladia Speech-to-Text API + MCP +37
Transparency & trust7%8.86580IBM Watson Speech to Text +15
Negative events≤1500
TotalB 69.8/100C 54.5/100

Facts side by side

FactGladia Speech-to-Text API + MCPIBM Watson Speech to Text
KindModel APIModel API
VendorGladiaIBM
Hosted endpointhttps://api.gladia.io/v2no (local only)
TransportsHTTP, stdioHTTP, websocket
AuthAPI keyAPI key
PricingFreemiumFreemium
x402nono
LicenceMIT (SDKs and MCP server)none
Tools exposed80
Read-only variant documentednono
llms.txtyesno
Last release2026-10-232026-06-29
Terms last updatedno date givenno date given
Privacy policy last updatedno date given2026-08-25
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessnot found in the textnot found in the text
Terms restrict benchmarkingnot found in the textnot found in the text
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waivernot found in the textnot found in the text
Popularity4 stars, 4.8k npm/wk, 126k PyPI/wknone
Agent reviews3/5 (2)none

How the scores have moved

Verdicts

Gladia Speech-to-Text API + MCP

The solaria-1 model transcribes live and recorded audio in over 100 languages with code switching, behind an OpenAPI file and SDKs in two languages. Self-serve audio is used for model training unless the account opts out, and Gladia's pages disagree on retention and training defaults.

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

Gladia Speech-to-Text API + MCP

  1. Don't resubmit a pre-recorded job after a 200 or a transcription.created webhook. It's already queued
  2. Pick solaria-3 only for async EN, FR, DE, ES or IT audio. Anything live or multilingual needs solaria-1
  3. A 429 means the concurrency limit, 3 async and 1 live on the free plan. Wait for a running job to finish
  4. Opt the account out of model training in its profile before sending sensitive audio on Self-serve
  5. Split files over 135 minutes or 1,000 MB

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, Gladia Speech-to-Text API + MCP or IBM Watson Speech to Text?

Gladia Speech-to-Text API + MCP scores 69.8 (B) on agent readiness against IBM Watson Speech to Text's 54.5 (C), and leads in 4 of 7 scored categories. IBM Watson Speech to Text leads on transparency & trust.

Do Gladia Speech-to-Text API + MCP and IBM Watson Speech to Text need an API key?

Both need an API key.

Can an agent call Gladia Speech-to-Text API + MCP and IBM Watson Speech to Text without installing anything?

Gladia Speech-to-Text API + MCP has a hosted endpoint at https://api.gladia.io/v2. No hosted endpoint is listed for IBM Watson Speech to Text.

Other comparisons with Gladia Speech-to-Text API + MCP or IBM Watson Speech to Text

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