Jsecurity
Tokyo, JP · Public · 1 known investors
A Japanese cybersecurity vendor that provides security products including anti-ransomware protection, spam filtering, and web application defense. Its offerings detect, block, and recover from ransomware encryption attacks.
Also known as JSecurity, Inc. · ジェイセキュリティ · 株式会社JSecurity
Founders & leadership
Investors · 1
Company profile
researched Aug 2026株式会社JSecurity (JSecurity, Inc.) is a Tokyo-based company whose stated business is the development and sale of information security products and services. It operates under the slogan "All for Japan Security" and positions its portfolio as security solutions for Japanese IT environments. The company was established in January 2018, has capital of JPY 50,000,000, a December fiscal year end, and is headquartered on the 17th floor of the World Trade Center Building South Tower in Hamamatsucho, Minato-ku, Tokyo.
The product line spans several categories: AppCheck for ransomware protection, which uses context/situational-awareness detection of unknown ransomware without pattern-file updates and includes file backup and restore functions; MudFix, a simulated targeted-attack email training and education service with optional consulting support for planning and configuring exercises; SPAMSNIPER (and SPAMSNIPER AG) for spam and virus mail blocking, real-time inbound filtering, misdelivery prevention and mail/file sanitization, available on-premises and in the cloud; MAILSCREEN for email misdelivery prevention and detection of personal information in message bodies and attachments; PCFILTER for discovering, visualizing, isolating, encrypting and deleting personal information stored on PCs; DarkWebCheck, a cloud service that continuously monitors the dark web for leaked information using only domain information; GIGAPOD, enterprise online storage used as a large-file transfer and PPAP countermeasure; Gate4Mobile, which provides access to and write capability on internal file servers from iPads; and SECURITY ONE, an information security education content platform.
As of company disclosures, the board comprises Representative Director and President Yoichi Imamura (今村誉一), directors Li Xiaoyan (李瀟燕) and Takuya Kobayashi (小林拓矢), and auditors Fumihide Kanazawa (金澤史英) and Yuki Tsukuda (佃友貴). The company listed on the Tokyo Stock Exchange's TOKYO PRO Market on 24 December 2025 with securities code 481A, and is classified as a computer/IT services business of spin-off or carve-out origin.
Business model
JSecurity develops and sells information security products and services to organizations, offering products across ransomware defense, email security, endpoint personal-information management, dark web monitoring, security training and file sharing. Contract forms indicated on its contact form include direct in-house deployment, deployment for a customer's own clients, and sales partnerships, indicating both direct and channel/OEM-style distribution. Third-party profiles categorize the business as B2B (and B2C) SaaS and subscription software.
Product and service sales of information security software, characterized in third-party profiles as subscription/SaaS software, with cloud and on-premises deployment options for products such as SPAMSNIPER and consulting services available alongside MudFix training.
Traction
More than 350,000 people have used the MudFix targeted-attack email training and education service, with training reportedly able to start in as little as five minutes; GIGAPOD reports deployments at over 4,000 customer companies. Headcount is reported at up to 50 employees, and the company completed a TOKYO PRO Market listing in December 2025.
Latest developments
In July 2026 JSecurity announced an offline-environment version of its AppCheck ransomware countermeasure solution. Preceding developments include the December 2025 TOKYO PRO Market listing, a September 2025 investment in STONE.B, and the September 2025 launch of a training-delivery (agency) service for MudFix.
▸Full profile — market position, technology, go-to-market, geography, history
Market position
A Japanese information security vendor with a multi-product portfolio; its GIGAPOD enterprise online storage is described as having been deployed at more than 4,000 customer companies, and its MudFix targeted-attack email training service is described as having been used by more than 350,000 people. External startup databases profile it primarily as the operator of the SPAMSNIPER anti-spam solution.
Signature-free ransomware detection with built-in backup and restore in AppCheck, a breadth of products covering email, endpoint, dark web monitoring, file sharing and security education under one vendor, and a stated focus on solutions for Japanese IT security needs.
Technology
AppCheck relies on situational/context-awareness technology to detect and block unknown ransomware without requiring signature (pattern file) updates, and provides file backup and restore for recovery. SPAMSNIPER performs real-time filtering of spam and virus mail, with the AG variant adding mail and file sanitization; MAILSCREEN and PCFILTER apply personal-information search and detection plus encryption, isolation and secure deletion. DarkWebCheck continuously monitors dark web sources for leaked data based on a customer's domain information.
Go-to-market
Direct sales and evaluation/trial requests through the company website, supported by press releases, a news and blog channel, seminars and events, and a reseller/sales-partner track; contact options distinguish in-house deployment, deployment to a customer's own clients, and partner sales.
Japanese enterprises and organizations of varying size, from small and medium businesses to global companies, including employees and staff who receive targeted-attack email training and field workers using iPads to access internal file servers.
Geography
Headquartered in Hamamatsucho, Minato-ku, Tokyo, Japan, directly connected to JR Hamamatsucho Station and three minutes from Daimon Station; business focus is on the Japanese market.
History
Established in January 2018 (incorporation date recorded as 4 January 2018) with origins described as a spin-off/carve-out, the company built out a portfolio of email security, ransomware, endpoint and file-sharing products. In September 2025 it announced an investment in STONE.B, operator of "mahocast," alongside GENDA Capital, ZVC and JIRAN JAPAN, and later that month began offering an outsourced training-delivery option for MudFix. It listed on the TOKYO PRO Market on 24 December 2025, and in July 2026 launched an offline-environment version of AppCheck.
Compiled by commissioned research from 8 cited public sources — announcements, filings, and press listed under research sources below.
Key figures
latest reportedCompany-reported or press-reported figures, each dated to when it was claimed — not independently audited.
Timeline · 4
launches, deals, and filingsJSecurity began providing a version of its AppCheck ransomware countermeasure solution for offline environments.
JSecurity completed a new listing on the Tokyo Stock Exchange's TOKYO PRO Market, with securities code 481A.
The company began offering a training-delivery (agency) service for its MudFix targeted-attack email training solution.
JSecurity invested in 株式会社STONE.B, operator of the "mahocast" service, alongside GENDA Capital, ZVC and JIRAN JAPAN.
Dated company events from announcements, filings, and press; legal rows summarize public dockets and regulator releases.
▸Research sources · 8
primary sources listed
- Jsecurityjsecurity.co.jp · web
8 public sources were cited for this profile; the first-party ones are listed here.
Frequently asked questions
- What does Jsecurity do?
- Tokyo-based information security vendor selling anti-ransomware, email security, dark web monitoring and file sharing products.
- Who are Jsecurity's investors?
- Jsecurity's investors include Colopl Next.
- Where is Jsecurity headquartered?
- Jsecurity is headquartered in Tokyo, JP.