For teams that need ISO 27001, NIS2, and GDPR evidence without handing compliance data to a SaaS vendor, ISMS Builder is a self-hosted information security management system for policies, risks, assets, audits, and incidents. Compliance managers move policies from draft through review to approved and archived, and recipients confirm each one through a token link that needs no login. Security officers close gaps in a Statement of Applicability that cross-maps BSI IT-Grundschutz, NIS2, EUCS, the EU AI Act, and the Cyber Resilience Act, with ISO 27001 controls imported from their own licensed copy. Risk owners keep treatment plans, turn Greenbone and OpenVAS reports into risk drafts, and score assets for confidentiality, integrity, availability, and authenticity. Data protection officers run records of processing, processor agreements, impact assessments, data subject requests, a 72-hour timer, and a deletion log with email alerts. The CISO inbox collects incidents, including reports from a public form that needs no login, beside a 30-item NIS2 Article 21 checklist and Article 23 deadline alerts. Auditors work from a findings register, a compliance matrix, and an exportable audit log of every create, update, delete, and login. Administrators enforce TOTP two-factor sign-in, choose among German, English, French, and Dutch, run semantic search locally through Ollama, and publish approved policies to Nextcloud or ownCloud as PDFs. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.