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

Inworld STT vs MiniMax Speech-to-Text

Inworld STT scores 54.7 (C) on agent readiness against MiniMax Speech-to-Text's 48.4 (D), and leads in 4 of 7 scored categories. MiniMax Speech-to-Text leads on schema & documentation and agent ergonomics. Both do speech-to-text.

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

Which one, for what

Inworld STT C

Best for Low-cost live transcription for voice agents, with speaker traits.

Ahead on

  • Reliability, 60 against 47
  • Security & auth, 63 against 33
  • Payments & pricing, 40 against 20
  • Maintenance & community, 41 against 6

Also in its favour

  • Free to start without a card

Watch for

No OpenAPI or other machine-readable contract

MiniMax Speech-to-Text D

Best for Cheap file transcription with diarisation and subtitles, strongest on Chinese and code-switched audio by the vendor's account.

Ahead on

  • Schema & documentation, 82 against 54
  • Agent ergonomics, 70 against 56

Watch for

Files only, up to 500 seconds and 50 MB; live audio input isn't supported

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.

Maintenance & community Inworld STT +35

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.

MiniMax Speech-to-Text 6

Read as a model. No dated release or change of asr-1.0 was found on the model or API release notes or the status page (0). No dated ASR entries in the last 90 days (0). Support by email and Discord, not tested (6 of 15). No official SDK, and the MCP servers have no transcription tool (0 of 15). No package to judge (0 of 10). Total 6.

Security & auth Inworld STT +30

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.

MiniMax Speech-to-Text 33

Model reading of the checklist, with training and retention in place of the least-privilege and injection lines. Plain API keys from the console with no scopes found, and the docs say publicly leaked keys may be disabled, as on minimax-voice-cloning (20 of 30). The terms (effective 30 March 2026), as read for minimax-voice-cloning on 4 November, let MiniMax use input and generated content to operate, maintain, develop and improve its services, with no opt-out found, and the privacy policy rules out only training to profile or target consumers (5 of 20). No retention period for uploaded audio or transcripts was found (3 of 15). Each response carries a trace ID, with no audit log found (5 of 15). No security.txt, disclosure policy, bug bounty or certification found, as on the other MiniMax listings (0 of 20). Total 33.

Schema & documentation MiniMax Speech-to-Text +28

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.

MiniMax Speech-to-Text 82

OpenAPI 3.1 for /v1/speech_to_text, with eight documented responses (25). llms.txt and a Markdown copy of every page (10). The guide says when to stream, when to use verbose_json, and that subtitles and diarisation can't be combined with streaming (15 of 20). Typed multipart fields with an enum for response_format, and file limits stated in prose (12 of 15). Python examples and an error table giving HTTP status, error.type and trigger for 400, 401, 402, 413, 422, 429 and 500 (15). Versioned /v1 path, but neither release notes page mentions the ASR API, and the API notes stop at 28 October 2025 (5 of 15). Total 82.

Payments & pricing Inworld STT +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.

MiniMax Speech-to-Text 20

No x402, MPP or L402 (0). $0.38 an hour published without a login (20). Speech to text is for paid accounts only (0). A person signs up in a browser and funds a balance (0). Total 20.

Agent ergonomics MiniMax Speech-to-Text +14

Inworld STT 56

API reading of the checklist. Voice Profile, word timestamps and diarisation are opt-in, and responses carry a usage block (18 of 25). No lists to page. Async jobs return an operation to poll (8 of 20). Errors carry a numeric gRPC code and message on both endpoints, but a malformed first message closes the socket with 1005 and no frame (12 of 20). Sync calls are stateless and async calls return an operation, with no idempotency key, and empty transcripts and add-ons are billed (10 of 20). A call needs a model, an encoding and the audio. No STT SDK was found, only the CLI and its MCP server and REST examples (8 of 15). Total 56.

MiniMax Speech-to-Text 70

API reading of the checklist. The default json returns only text, duration and a trace ID, with segments and subtitles opt-in (22 of 25). No lists to page. response_format and language are the output controls (12 of 20). Typed error envelopes with the real HTTP status, an error type and request_id, and 402 for an empty balance (18 of 20). Calls are synchronous with no idempotency key (10 of 20). Two fields, a model and a file. No official SDK, and MiniMax's MCP servers don't cover transcription (8 of 15). Total 70.

Reliability Inworld STT +13

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.

MiniMax Speech-to-Text 47

Atlassian Statuspage at status.minimax.io with component history, but its components are LLM, Text-to-Speech and Video Generation, with none for speech to text (10 of 20). With no component, the history holds no record for transcription (5). Limits published with numbers, 2 concurrent connections and 30,000 audio seconds a minute (15). 429 is documented as rate_limit_error, and the general error code page says to retry later, with no backoff figures or Retry-After (7 of 15). No SLA in the terms or docs (0). asr-1.0 is called the current public model with no beta label (10). 10 + 5 + 15 + 7 + 0 + 10 = 47.

Score by category

CategoryWeight this runInworld STTMiniMax Speech-to-TextEdge
Reliability16%206047Inworld STT +13
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25482MiniMax Speech-to-Text +28
Agent ergonomics13%16.25670MiniMax Speech-to-Text +14
Security & auth14%17.56333Inworld STT +30
Payments & pricing10%12.54020Inworld STT +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8416Inworld STT +35
Transparency & trust7%8.86063MiniMax Speech-to-Text +3
Negative events≤1500
TotalC 54.7/100D 48.4/100

Facts side by side

FactInworld STTMiniMax Speech-to-Text
KindModel APIModel API
VendorInworld AIMiniMax
Hosted endpointno (local only)no (local only)
TransportsHTTP, websocketHTTP
AuthAPI keyAPI key
PricingPay per usePay per use
Price for speech-to-text$0.0017 per minute of audionot published
x402nono
Tools exposed00
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-29none
Terms last updated2025-06-11couldn't be read
Privacy policy last updated2026-01-18couldn't be read
Customer content may train modelsnot found in the textcouldn't be read
Terms restrict automated accessnot found in the textcouldn't be read
Terms restrict benchmarkingnot found in the textcouldn't be read
Terms or service can change without noticenot found in the textcouldn't be read
Arbitration or class-action waivernot found in the textcouldn't be read

What the same task costs

TaskInworld STTMiniMax Speech-to-Text
Transcribe a one-hour meeting60 minutes of recorded audio$0.10 to $0.15$0.38

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

Verdicts

Inworld STT

Inworld STT costs $0.10 to $0.15 an hour with 400 free minutes, and covers files, live streams and async jobs in 30 languages with Voice Profile signals. There is no machine-readable spec, no public STT changelog and no readable status history, and diarisation is still experimental.

MiniMax Speech-to-Text

MiniMax's ASR API has an OpenAPI file, typed error envelopes and a public price of $0.38 an hour, with diarisation and subtitle output. It takes files of up to 500 seconds only, allows 2 concurrent connections, has no free tier or status component, and no dated release.

Before you call either

Inworld STT

  1. Send the Base64 credential as-is in Authorization: Basic; don't encode it again
  2. Wrap the first WebSocket message in transcribeConfig, because a malformed first frame closes the socket with 1005 and no error
  3. Use POST /stt/v1/transcribe:async for files over about 16 MB and collect the transcript within 7 days
  4. Retry 429 or gRPC code 8 with exponential backoff and jitter, and stay within the plan's streaming concurrency
  5. Stop sending audio when nobody speaks, since streams are billed for every second sent

MiniMax Speech-to-Text

  1. Split recordings into pieces under 500 seconds before uploading, since longer audio returns 400
  2. Convert to mono 16 kHz or a compressed format to stay under 50 MB
  3. Use verbose_json for speakers and timestamps, and json only when streaming
  4. Treat 402 insufficient_balance_error as final and ask the user to top up
  5. Use https://api.minimaxi.com for a mainland China account

Questions

Which is better for AI agents, Inworld STT or MiniMax Speech-to-Text?

Inworld STT scores 54.7 (C) on agent readiness against MiniMax Speech-to-Text's 48.4 (D), and leads in 4 of 7 scored categories. MiniMax Speech-to-Text leads on schema & documentation and agent ergonomics.

Do Inworld STT and MiniMax Speech-to-Text need an API key?

Both need an API key.

Can an agent call Inworld STT and MiniMax Speech-to-Text without installing anything?

No hosted endpoint is listed for Inworld STT. No hosted endpoint is listed for MiniMax Speech-to-Text.

Other comparisons with Inworld STT or MiniMax Speech-to-Text

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