Kotoba Technologies
Kotoba Technologies develops Koto, a proprietary end-to-end voice AI foundation model for real-time speech translation, ASR, and TTS optimized for East Asian languages. It serves consumers via a mobile interpretation app, enterprise customers through model licensing, and developers via a Python SDK.
- Company typePrivate
- Founded2023
- HeadquartersSan Francisco, United States
- Headcount11–50
- GTM typeB2B and B2C
- OfferingSoftware
What Kotoba Technologies does
Kotoba Technologies is a privately held voice AI company founded in 2023 that develops Koto, a proprietary end-to-end foundation model for real-time speech applications including speech-to-text (ASR), text-to-speech (TTS), and speech-to-speech (S2S) simultaneous translation. The company specializes in East Asian languages (Japanese, Korean, Chinese) with secondary support for English and Spanish, and claims benchmark-leading latency and quality versus leading American and European models on CJK pairs (e.g., 2.6x faster Ko→Ja translation, sub-50ms TTS on H100, sub-2-second S2S translation). Koto is deployable on-premise, on-cloud, or on-device for embedded and edge applications.
The company monetizes through three primary channels: a consumer-facing Kotoba mobile app with a freemium tier (5 hrs/mo free), $99/month Unlimited subscriptions, and $95/device/month Enterprise plans; direct enterprise model licensing to Fortune Global 500 companies and AI-native startups for AI agents, contact center voice interfaces, and embedded translation; and a newly launched (May 2026) Kotoba API and Python SDK in private alpha. Distribution extends to enterprise and consumer segments via SoftBank's 'Daredemo AI' carrier platform, jig.jp SABERA smart glasses OEM integration, and event/conference partnerships (NVIDIA AI Summit Japan 2024, SusHi Tech Tokyo 2026). The company is headquartered in San Francisco with principal R&D in Tokyo, holds ISO/IEC 27001:2022 certification, and has raised approximately $23M in total seed funding from Kindred Ventures, Salesforce Ventures, Sony Innovation Fund, Globis Capital Partners, Boost Capital, and SIP Capital.
Kotoba Technologies firmographics
Firmographics- Name
- Kotoba Technologies
- Legal name
- Kotoba Technologies, Inc.
- Website
- https://kotoba.tech
- Company type
- Private
- Founded year
- 2023
- Operating status
- Operating
- Headcount range
- 11–50 employees
- Short description
- Kotoba Technologies develops Koto, a proprietary end-to-end voice AI foundation model for real-time speech translation, ASR, and TTS optimized for East Asian languages. It serves consumers via a mobile interpretation app, enterprise customers through model licensing, and developers via a Python SDK.
- Ownership category
- akta.pro rank
Kotoba Technologies industry classification
Industry- Product category
- Speech AI / Real-time Translation Software
- NAICS
- Software Publishers (51321)
- SIC
- Services-Prepackaged Software (7372)
- akta.pro primary industry
- Speech Translation & Multilingual Speech Tech (HDAAAFAE)
- akta.pro secondary industry
- Multilingual/Translation Communication Apps (BPAMACAJ)
Keywords
Where Kotoba Technologies is headquartered
LocationHeadquarters
- HQ city
- San Francisco
- HQ country
- United States
- HQ region
- North America
Offices2 records
Markets served
Kotoba Technologies business model
Business model- GTM type
- B2B and B2C
- Offering type
- Software
- Cost components
- Personnel, Technology or R&D, Marketing or Sales, Operations, Infrastructure
Revenue model
- Consumer App Subscriptions: Mobile app 'Kotoba' (同時通訳) with Free tier (5 hours/month), Unlimited plan ($99/month or $999.99/year on iOS, $99/month on Android), driving direct consumer revenue through App Store and Google Play subscriptions.
- Enterprise Licenses: Model licensing of Koto to enterprise customers including Fortune Global 500 companies and AI-native startups for AI voice agents, voice interfaces for contact centers, wearable devices, and simultaneous translation. Includes on-premise and on-device deployment options.
- API/SDK Access: Alpha release of Kotoba API and Python SDK enabling developers to evaluate speech-to-speech, streaming STT, and TTS models. Path to production API access and dedicated API capacity after evaluation.
- Platform Distribution Partnerships: Integration into third-party platforms (e.g., SoftBank 'Daredemo AI') generating revenue through promotional partnerships and potential referral/subscription conversion fees.
Pricing tiers
| Model | Billing | Price |
|---|---|---|
| Freemium | Monthly | Free tier with 5 hours of translation per month |
| Subscription | Monthly | Unlimited professional interpretation at $99/month |
| Per seat | Monthly | Enterprise team plan at $95/device/month |
Go-to-market motion3 records
Distribution channels5 records
Marketing channels5 records
Kotoba Technologies product offering
Product offeringCore offering
Kotoba Technologies develops and commercializes Koto, a proprietary end-to-end voice AI foundation model for real-time speech applications including speech-to-text (ASR), text-to-speech (TTS), and speech-to-speech (S2S) simultaneous translation. The company delivers the model through a consumer mobile app (Kotoba App), an enterprise API/SDK, and direct model licensing to Fortune Global 500 customers, with deployment options spanning cloud, on-premise, and on-device edge environments.
Product overview
Kotoba Technologies offers a unified voice AI platform centered on the Koto foundation model, a proprietary real-time speech AI providing speech-to-speech translation, speech-to-text (ASR), and text-to-speech synthesis. The platform delivers to both consumers via the Kotoba App (同時通了) for simultaneous interpretation across 21 input and 13 output languages, and to developers/enterprises via the Kotoba API & SDK for programmatic integration. A prior product, DOTSU, served as an earlier iOS speech-to-text interpretation app. The company also maintains a strategic partnership with SABERA smart glasses for AR-integrated translation.
Differentiator
Problem solved
Functional benefit
Brands
- Koto: Proprietary speech AI foundation model for real-time speech applications including speech-to-text, text-to-speech, and speech-to-speech simultaneous translation, optimized for East Asian languages (Japanese, Korean, Chinese).
- Kotoba API & SDK
Products and services
- Koto Voice AI Foundation Model Proprietary end-to-end voice AI foundation model for real-time speech applications including AI agents, smart hardware, and simultaneous speech translation. Supports speech-to-speech (S2S), speech-to-text (ASR), and text-to-speech (TTS). Deployable on-premise, on-cloud, or on-device (smartphones and wearables) with industry-leading performance for Japanese, Korean, and Chinese. Licensed to enterprise customers and Fortune Global 500 companies.
- Kotoba API & SDK Private alpha API and Python SDK providing programmatic access to the Koto foundation model with three model families: Speech-to-Speech Translation (S2ST), Streaming STT/ASR, and Streaming TTS. WebSocket-based real-time streaming achieves sub-second latency; REST-based Transcription API handles batch and offline workflows. Supports Japanese, Chinese, Korean, English, and Spanish. Available to selected customers for evaluation with path to production licensing.
- Kotoba Mobile App (同時通訳) Consumer-facing mobile app delivering real-time simultaneous interpretation with voice and text output. Features predictive translation displayed up to 0.5 seconds ahead and sub-1-second speech-to-translation latency. Supports 21 input and 13 output languages centered on Japanese, English, Chinese, Korean, and Spanish. Free tier (5 hours/month), Unlimited ($99/month), and Enterprise ($95/device/month) plans. Ranked #1 in the translation category on App Store and Google Play.
- DOTSU iOS App Speech-to-text simultaneous interpretation iOS app launched March 2025. Achieved 500,000 sessions within three months with sub-500ms latency. Featured on TV Tokyo and major media for fast translation performance. Served as an earlier consumer product ahead of the Kotoba App rebrand and expansion.
Quantifiable outcome
- Sub-2-second speech-to-speech latency with 1.96s on Ko→Ja (2.6x faster than leading competitor at 5.06s)
- +3 more outcomes
Companies that use Kotoba Technologies
Customer profileNamed customers5 records
Segments5 records
Ideal customer profiles4 records
Kotoba Technologies technology and API
TechnologyTechnology focussed Yes
API detail
- Has API
- Yes
- API docs
- API detail
Core technology
AI maturity
App detail
Integration2 records
AI capability6 records
Feature6 records
Kotoba Technologies partnerships and signals
Strategic signalPartnerships
Two partnerships are on record, tiered core.
- jig.jp Co., Ltd.coreStrategic partnership to integrate Kotoba's ultra-low-latency real-time translation into SABERA smart glasses by jig.jp. Combines SABERA's AR display technology with Kotoba's voice AI to deliver real-time interpretation displayed in the wearer's field of view. Joint solutions, mutual customer referrals, and bundled enterprise offerings planned.
- SoftBank Corp.coreIntegration of Kotoba real-time interpretation app into SoftBank's 'Daredemo AI' platform. Users can access Kotoba's simultaneous interpretation experience through the platform. Special promotional pricing for SoftBank, Y!mobile, and LINEMO subscribers (approx. 94% off for 3 months). Also marks official release of Japanese-Korean simultaneous interpretation model.
Scale indicators10 records
Recent moves6 records
Expansion highlights8 records
Kotoba Technologies competitors and assessment
Company assessmentBroad incumbents
- Google (Translate & Cloud Speech): Google offers Google Translate consumer app and Cloud Speech-to-Text/Translation APIs with broad language coverage. It is the benchmark incumbent that Kotoba's app surpassed in the Japan/Korea translation category and whose speech APIs compete with Koto for enterprise translation workloads.
- OpenAI: OpenAI's Whisper, GPT-4o Realtime, and TTS APIs offer speech-to-text, speech-to-speech, and voice synthesis with global language coverage. As a broad foundation-model incumbent, it competes directly with Koto on speech quality and latency benchmarks.
- Microsoft (Azure AI Speech): Microsoft Azure AI Speech delivers speech-to-text, text-to-speech, and speech translation across 100+ languages with enterprise-grade deployment. It competes with Kotoba for enterprise translation licensing and is also a Salesforce Ventures' portfolio adjacency.
Direct peers
- DeepL: DeepL provides AI-powered translation with strong accuracy reputation, expanding into voice and enterprise APIs. It is a directly comparable translation-first competitor, although its East Asian language coverage is historically weaker than its European strengths, mirroring Kotoba's positioning.
- ElevenLabs: ElevenLabs is a frontier voice AI company delivering ultra-low-latency TTS, voice cloning, and conversational agents via API. It directly competes with Kotoba's TTS offering on quality and latency benchmarks for enterprise and developer customers.
- iFlytek: iFlytek is China's leading speech recognition, synthesis, and translation provider with deep CJK language expertise. It is a direct competitor in the East Asian simultaneous interpretation market and is known for benchmarking strongly on Chinese speech tasks.
- Naver Papago: Naver's Papago is a leading Korean-origin translation app and API with strong Korean, Japanese, and Chinese performance. It is a directly comparable prosumer-and-API translation product competing with Kotoba in the Korean market.
Emerging players
- Soniox: Soniox is a speech AI startup offering multilingual speech-to-text and translation APIs with strong accuracy claims. It is an emerging direct competitor in the developer-focused speech AI space where Kotoba is launching its API/SDK alpha.
- Deepgram: Deepgram provides low-latency ASR, TTS, and conversational AI APIs for enterprise and developer customers. It competes with Kotoba's streaming STT offering on latency and accuracy, though its East Asian language depth is less established.
- AssemblyAI: AssemblyAI offers speech-to-text and speech understanding APIs targeted at developers and enterprises building voice products. It is an emerging adjacent competitor in the developer speech AI category where Kotoba is positioning its API alpha.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat5 records
Key risks5 records
Key highlights7 records
Customer concentration
Kotoba Technologies social profiles
Digital presenceKotoba Technologies compliance and trust
Trust signalCompliance1 record
Kotoba Technologies financial estimates
Financial estimateRevenue estimate
Valuation estimate
Kotoba Technologies leadership team
Management profileNumber of profiles
Profiles3 records
Kotoba Technologies subsidiaries and ownership
Company hierarchySubsidiaries1 record
Kotoba Technologies funding detail
Funding detailFunding overview
Funding rounds3 records
Investors7 records
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Kotoba Technologies M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Kotoba Technologies
What does Kotoba Technologies do?
Kotoba Technologies develops and commercializes Koto, a proprietary end-to-end voice AI foundation model for real-time speech applications including speech-to-text (ASR), text-to-speech (TTS), and speech-to-speech (S2S) simultaneous translation. The company delivers the model through a consumer mobile app (Kotoba App), an enterprise API/SDK, and direct model licensing to Fortune Global 500 customers, with deployment options spanning cloud, on-premise, and on-device edge environments.
Is Kotoba Technologies a public or private company?
Kotoba Technologies is a private company. It is classified as venture growth investor backed and is currently operating.
When was Kotoba Technologies founded?
Kotoba Technologies was founded in 2023. It employs 11 to 50 people.
Where is Kotoba Technologies based?
Kotoba Technologies is headquartered in San Francisco, United States, in the North America region.
How does Kotoba Technologies make money?
Four revenue lines are on record. Consumer App Subscriptions are the primary driver. The others are enterprise Licenses, API/SDK Access and platform Distribution Partnerships.
Who are Kotoba Technologies's main competitors?
Broad incumbents on record are Google (Translate & Cloud Speech), OpenAI and Microsoft (Azure AI Speech). Direct peers are DeepL, ElevenLabs, iFlytek and Naver Papago. Emerging players are Soniox, Deepgram and AssemblyAI.
Does Kotoba Technologies have an API?
Yes. Private alpha API providing real-time speech APIs including Speech-to-Speech Translation (S2ST), Streaming Speech-to-Text (STT/ASR), and Text-to-Speech (TTS). The Realtime APIs use WebSocket connections for sub-second latency streaming, while a REST-based Transcription API handles batch/offline workflows. Authentication supports server-side Bearer tokens and browser/client-side short-lived secrets via Sec-WebSocket-Protocol. Available to selected customers for evaluation with path to production licensing. Developer documentation is at docs.kotoba.tech.
What industry is Kotoba Technologies in?
Kotoba Technologies's product category is Speech AI / Real-time Translation Software. Its primary akta.pro industry code is HDAAAFAE, Speech Translation & Multilingual Speech Tech, with a secondary code of BPAMACAJ, Multilingual/Translation Communication Apps. Its NAICS code is 51321 and its SIC code is 7372.