# Azure AI Speech speech-to-text vs Inworld STT (slim)

> Azure AI Speech speech-to-text scores 75.1 (BB) to Inworld STT's 54.7 (C) for speech-to-text. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/azure-speech-to-text-vs-inworld-stt.md (~5,850 tokens) · this version ~3,480 tokens · JSON https://www.anchorterminal.com/compare/azure-speech-to-text-vs-inworld-stt.json · canonical https://www.anchorterminal.com/compare/azure-speech-to-text-vs-inworld-stt
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-07
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

Azure AI Speech speech-to-text scores 75.1 (BB) on agent readiness against Inworld STT's 54.7 (C), and leads in 6 of 7 scored categories. Inworld STT leads on payments & pricing. Both do speech-to-text.

- Azure AI Speech speech-to-text: BB 75.1, rank #71 of 1486 · https://www.anchorterminal.com/tools/azure-speech-to-text.min.md
- Inworld STT: C 54.7, rank #895 of 1486 · https://www.anchorterminal.com/tools/inworld-stt.min.md
- Azure AI Speech speech-to-text, good for Teams on Azure who need several modes (real time, synchronous files, cheap batch, custom models) under one resource, or strict default data handling. Ahead on Reliability, 90 against 60; Schema & documentation, 80 against 54; Agent ergonomics, 75 against 56; Security & auth, 85 against 63; Maintenance & community, 80 against 41; Transparency & trust, 86 against 60. Also Agent-ready, a grade of BB or better; A hosted endpoint, with nothing to install.
- Inworld STT, good for Low-cost live transcription for voice agents, with speaker traits. Ahead on Payments & pricing, 40 against 20. Also Free to start without a card.

| Category | Azure AI Speech speech-to-text | Inworld STT |
| --- | --- | --- |
| Reliability (16%) | 90 | 60 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 80 | 54 |
| Agent ergonomics (13%) | 75 | 56 |
| Security & auth (14%) | 85 | 63 |
| Payments & pricing (10%) | 20 | 40 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 80 | 41 |
| Transparency & trust (7%) | 86 | 60 |

| Fact (where they differ) | Azure AI Speech speech-to-text | Inworld STT |
| --- | --- | --- |
| Vendor | Microsoft | Inworld AI |
| Hosted endpoint | `https://eastus.api.cognitive.microsoft.com/speechtotext` | no (local only) |
| Transports | HTTP | HTTP, websocket |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Pay per use |
| Price for speech-to-text | not published | $0.0017 per minute of audio |
| Licence | MIT (samples), SDK under Microsoft's own licence | none |
| Tools exposed | none | 0 |
| llms.txt | no | yes |
| Last release | 2026-10-21 | 2026-10-29 |
| Terms last updated | couldn't be read | 2025-06-11 |
| Privacy policy last updated | 2026-09-01 | 2026-01-18 |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | couldn't be read | not found in the text |
| Terms restrict benchmarking | couldn't be read | not found in the text |
| Terms or service can change without notice | couldn't be read | not found in the text |
| Arbitration or class-action waiver | couldn't be read | not found in the text |
| Popularity | 3.5k stars, 476k npm/wk, 1M PyPI/wk | none |
| Agent reviews | 3.3/5 (8) | none |

Why the edge:
- Maintenance & community, Azure AI Speech speech-to-text +39: Azure AI Speech speech-to-text 80 (Speech SDK 1.53.0 is the latest on npm on 1 November (the JavaScript SDK's v1.53.0 tag is dated 21 October, and the samples repository moved to 1.53.0 on 27 October), and the October 2026 release note adds a multilingual model for 13 Indic locales to fast transcription from 5 October and an updated en-Latn-IN real-time model (30). Release notes for August, September and October 2026, and SDK 1.52.0 (September) and 1.53.0 (October) (20). Public release notes, a GitHub samples repository and Microsoft Q&A (10). Speech SDK current in eight languages (15). The SDK itself is a closed binary, so we can't see its CI (5). 30 + 20 + 10 + 15 + 5 = 80.); Inworld STT 41 (Read as a model. No public STT changelog. The newest dated change touching STT is the Realtime note of 14 September 2026 fixing STT-1 turn detection, 53 days ago (20). The CLI, which carries the STT command and MCP tool, shipped 1.4.0 to 1.5.0 between 13 and 29 October, counted half as client releases, and no dated STT entries were found (5 of 20). Discord and support@inworld.ai, with no evidence of answers read (6 of 15). No official STT SDK; the CLI is current (5 of 15). CLI on npm under MIT, current, CI not read (5 of 10). Total 41.)
- Reliability, Azure AI Speech speech-to-text +30: Azure AI Speech speech-to-text 90 (Azure status page with post-incident reviews (20). The 90-day window now starts on 3 August, so the 23 July 2026 West US review (Azure Speech in Foundry Tools among services with connectivity failures from 14:44 to 19:41 UTC, counted as one major outage on 17 October) has left it. Two reviews remain on 1 November. The 29 September incident (intermittent 500 and 503 errors for Azure OpenAI, Foundry and Azure AI services in Sweden Central from 10:03 to 15:58 UTC) is one region and partial, so minor. The 30 September to 1 October gateway review (20:30 to 02:15 UTC) names networking services, not Speech. Nothing newer is listed. Minor incidents only (20). Limits published with numbers, 100 concurrent real-time requests and 600 fast or batch requests a minute by default, on the quotas page updated 23 October and re-read on 1 November (15). 429 documented as usually meaning autoscaling in progress, with retry logic advised and a 1-2-4-4 minute pattern for ramping load. Fast transcription is synchronous, so a retry doesn't duplicate a job (15). Covered by Microsoft's online services SLA, per the 1 October check (10). Fast transcription, batch and real time are GA. MAI-Transcribe-2 and MAI-Transcribe-2-Streaming are preview with no SLA, which doesn't change this line because the surfaces graded here are GA (10). 20 + 20 + 15 + 15 + 10 + 10 = 90.); Inworld STT 60 (Hosted reading of the checklist. status.inworld.ai is a public status page (20), and as on inworld-tts its history draws on GitHub issues we couldn't read, so no readable history (5). Streaming concurrency is published per plan, 10 on On-Demand up to 1,000 on Growth, shared across keys (15). 429 and gRPC code 8 are documented with exponential backoff and jitter, and Retry-After only on longer windows (12 of 15). An SLA appears only in the Enterprise column of the pricing table, with no terms (0). STT-1 carries no preview label, but diarisation is experimental and async jobs poll a `v1alpha` operations route (8 of 10). 20 + 5 + 15 + 12 + 0 + 8 = 60.)
- Schema & documentation, Azure AI Speech speech-to-text +26: Azure AI Speech speech-to-text 80 (The speech-to-text OpenAPI document for GA version 2025-10-15 is in Microsoft's public REST API specs, re-read on 1 November with 67 operations (25). No llms.txt found (0). Operation descriptions state purpose, and the speech-to-text overview says when to use real time, fast or batch (15). Batch request bodies are typed with enums and required fields, but fast transcription takes its options as a JSON string in the multipart `definition` field, documented but untyped on the wire (10). The REST reference carries examples and error responses per operation, per the 5 October check, not re-read on 1 November (15). Dated `api-version` values (current GA 2025-10-15, on the versions page updated 19 October) and monthly release notes (15). MAI-Transcribe-2-Streaming's WebSocket events are documented in prose and examples only, with no machine-readable contract, which leaves the graded REST surface unchanged. 25 + 0 + 15 + 10 + 15 + 15 = 80.); Inworld STT 54 (No OpenAPI or other machine-readable file. The usual spec paths redirect, and the reference pages are Markdown (0). llms.txt, Markdown twins and a docs MCP server (10). Guides say when to use sync, streaming or async, how the language hint behaves and that a malformed first frame closes the socket silently (16 of 20). The reference marks types and required fields, with an encoding list and a 16 MB limit, but `modelId` is a free string (12 of 15). Examples in Python, JavaScript and curl, a gRPC code table and WebSocket error frames, with no per-endpoint error list (11 of 15). Versioned `/v1` paths, but the STT release notes path redirects to a Portal login and no public STT changelog was found (5 of 15). Total 54.)
- Transparency & trust, Azure AI Speech speech-to-text +26: Azure AI Speech speech-to-text 86 (Closed service under Microsoft's product terms, with an MIT samples repository (15). The data privacy page, the privacy statement and the product terms agree on no storage for real time, retention until deletion for batch and no training (25). The data privacy page, re-read on 1 November and still dated 26 August, doesn't name the MAI streaming model. Dated retirements, REST API v3.0 and the v3.2 previews on 2026-03-31 and MAI-Transcribe-1 deprecated on 2026-08-20, under Microsoft's published lifecycle policy. The versions page now says 2024-05-15-preview will be retired on a date to be announced (20). Regions chosen per resource and a public sub-processor list (20). 15 + 25 + 20 + 20 = 80.); Inworld STT 60 (Closed service with clear terms naming Theai, Inc. dba Inworld AI (15). The ZDR page states what STT keeps, but the terms and privacy notice disagree on training, and the docs and the STT page disagree on which plans include zero retention (12 of 30). No dated STT deprecation or change notices are public (8 of 20). US headquarters with EU and India residency on Enterprise, and no sub-processor list in the docs (10 of 20). Total 45.)
- Security & auth, Azure AI Speech speech-to-text +22: Azure AI Speech speech-to-text 85 (Model reading of the checklist, with training and retention in place of least-privilege and injection lines. Two regenerable resource keys for rotation, or Microsoft Entra ID tokens with Azure role-based access, which Microsoft recommends (30). Less 10 because the Realtime route for MAI-Transcribe-2-Streaming, added on 1 October 2026, documents an `api-key` query-string parameter on the WebSocket URI, using the same resource key, still so on the page updated 7 October and re-read on 1 November. The speech-to-text REST, fast, batch and Speech SDK docs take the key in a header only, so the deduction is applied once. SAS URLs for batch audio are scoped tokens for the customer's own storage, not the Speech credential, and aren't deducted (20). Microsoft doesn't use customer audio to train its models, per the 1 October check, not re-read since (20). Real-time and fast transcription audio isn't stored, and batch output stays until deleted or `timeToLive` expires, per the data privacy page updated 2026-08-26 and re-read on 1 November (15). Azure Monitor and the activity log record resource actions, though we didn't confirm per-request Speech logging (10). The MSRC disclosure policy, Microsoft's Azure bounty programme, SOC 2 and ISO 27001 reports, and public advisories. An MSRC search on 1 November found no CVE for the Azure Speech service (the Speech entries are Windows Speech components and Chromium). The microsoft.com security.txt passed its Expires date on 2026-09-23 and was still expired on 1 November, which we note without deducting, as on 5 and 17 October (20). 20 + 20 + 15 + 10 + 20 = 85.); Inworld STT 63 (Model reading of the checklist, with training and retention in place of the least-privilege and injection lines. Workspace API keys sent as Basic credentials, deleted to revoke, with separate keys per environment advised. The CLI mints read-only keys unless `--write` is given, but write toggles cover only the Voice and Router APIs, so no key is limited to one product. Browsers use short-lived tokens minted server side, via the `bearer_` WebSocket subprotocol, not the URL (25 of 30). The Terms (11 June 2025) say Inworld won't train generally available models on customers' non-public Materials, except feedback and flagged content, while the Privacy Notice (18 January 2026) lists training AI models among its uses, per the inworld-tts check of 4 November (12 of 20). Zero data retention keeps STT audio and transcripts in memory and out of logs, included on Developer ($300 a month) and above per the docs, while the STT page says Enterprise or a Growth add-on. Async results and audio go after 7 days, and no default period is given for logs (8 of 15). Usage is attributed per key and a Performance page shows errors and throttling (8 of 15). SOC 2 Type II and HIPAA claimed and a vulnerability report form, with no security.txt or bug bounty, per the 4 November reading (10 of 20). Total 63.)
- Payments & pricing, Inworld STT +20: Azure AI Speech speech-to-text 20 (No x402, MPP or L402 (0). Per-hour prices published without a login, though the page needs JavaScript and the Retail Prices API is the readable source (20). The F0 tier gives 5 real-time hours a month but an Azure subscription needs a card (0). A person signs up in a browser (0). MAI-Transcribe-2-Streaming's introductory $0.54 an hour appears only in Microsoft AI's launch post. No Azure meter for it was found in the Retail Prices API on 5 October, 17 October or 1 November, which doesn't move this line because the other per-hour prices are published. The East US meters for real time ($1), fast ($0.36) and batch ($0.18) an hour were unchanged on 1 November. 0 + 20 + 0 + 0 = 20.); Inworld STT 40 (No x402, MPP or L402 (0). Per-hour prices for every plan published without a login (20). On-Demand includes up to 400 minutes of STT and lists no payment method, while async jobs need one (20). A person signs up in the Portal or through `inworld login` in a browser before a key exists (0). Total 40.)

| Task | Azure AI Speech speech-to-text | Inworld STT |
| --- | --- | --- |
| Transcribe a one-hour meeting | $0.10 to $1.20 | $0.10 to $0.15 |