# Kotoba

**Canonical:** https://apis.io/providers/kotoba/  
**Website:** https://kotoba.tech/  
**APIs profiled:** 1

Kotoba Technologies is a Japan-founded frontier voice AI company building a foundational real-time speech model and simultaneous translation technology. Its developer platform exposes three JSON-over-WebSocket realtime capabilities — ASR (automatic speech recognition with live transcript deltas), STS (speech-to-speech translation that emits both a source transcript and synthesized target-language audio over one connection), and TTS (streaming text-to-speech) — alongside a REST transcription API for batch and offline workflows built on a submit-and-poll job model. Supported languages span English, Japanese, Korean, Chinese and Spanish. Each realtime channel is described by a published AsyncAPI 2.6.0 document and each REST surface by OpenAPI 3.1, with a first-party Python SDK, an llms.txt agent index, and a live remote MCP documentation server. The APIs are in private alpha, available to selected customers on request.

## Kin Score — 46.8 / 100 (developing)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 46.8).

| Facet | Score |
|---|---|
| Discoverability | 87.0 |
| Contract Quality | 54.5 |
| Governance | 16.7 |
| Contract Governance | 16.7 |
| Operational Transparency | 18.4 |
| Developer Ergonomics | 66.1 |
| Commercial Clarity | 34.2 |
| Access Clarity | 34.2 |

## Agent readiness — 42.8 (agent-ready)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | no |
| MCP Server | documented |
| Auth Clarity | yes |
| Idempotency | no |
| Error Semantics | verified |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | derived |
| Agent Skills | derived |
| Well Known Catalog | yes |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Self-serve signup — onboarding: self-serve, pricing: unknown, trial: no (confidence: medium).

## APIs (1)

- **Kotoba transcriptionApi API** — The transcriptionApi API from Kotoba — 2 operation(s) for transcriptionapi.

## MCP servers (1)

- **Kotoba MCP Server**

## Agentic access (1)

- **Kotoba Agentic Access** — 2 operations · 1 acting

## Security (2)

- **Kotoba Authentication** — http/client-secret · 3 schemes
- **Kotoba Domain Security** — TLSv1.3 · HSTS

## Tags

Company, Artificial Intelligence, Machine-Learning, Voice, Speech Recognition, Speech-to-Text, Text-to-Speech, Translation, Real-Time, WebSockets, Audio, Transcription

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/kotoba/). Scores are computed from the provider's own public artifacts under a published rubric.