Keiji Kumagai｜熊谷渓司
Representative Director of CACTUS TOKYO Inc. He develops SayonaraType, a voice input app for Mac.
After working in corporate planning and corporate transformation at EBARA Corporation, he founded CACTUS TOKYO Inc. in 2022. He launched a D2C brand, calculating the CO2 emissions of each product in-house and disclosing them to customers. In 2025 he launched a SaaS for businesses, and sold it in 2026.
At SayonaraType, he built "ja-dictation-bench," a public benchmark that compares voice input apps on Japanese, and published everything down to the problems, the scoring criteria and the reasons for each judgment. The project started from his own frustration after years of typing large amounts of text every day: documents, emails and conversations with AI.