Startup Security Kit

Practical security guidance for startups and small teams, combining lightweight ISMS, developer security checklists, and secure backend patterns.

Security starter kit for startups and small teams.

This repository provides practical security guidance that small teams can realistically adopt.

Many security frameworks are designed for large enterprises and are too heavy for startups. Startup Security Kit focuses on lightweight and practical security practices.

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Features

This project includes three core components:

flowchart TD
A[ISMS Lite<br>Security Governance]
B[Developer Security Checklist<br>Secure Development Practices]
C[Secure Backend Patterns<br>Secure Implementation]

A --> B
B --> C

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ISMS Lite

A lightweight ISMS implementation designed for small teams.

Includes:

• security policy template
• asset register
• risk assessment template
• incident response guide
• internal audit guide

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PDCA Cycle

ISMS Lite follows a simplified PDCA cycle.

• Plan — define security policies and perform risk assessments
• Do — implement security controls and operational procedures
• Check — verify implementation through internal audits
• Act — improve security processes based on findings

This cycle enables small teams to continuously improve their security practices.

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Developer Security Checklist

A practical checklist for developers when designing or reviewing systems.

Topics include:

• authentication
• authorization
• API security
• secrets management
• logging and monitoring

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Secure Backend Patterns

Security architecture patterns for backend systems.

Examples include:

• JWT authentication design
• RBAC authorization
• secure API design
• audit logging
• secret management

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Target Audience

This project is designed for:

• startups
• small companies (1–10 people)
• developer-led teams
• backend engineers

Many small teams do not have dedicated security engineers. This project provides practical security guidance for such environments.

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Quick Start

1. Copy the security policy template
2. Create your asset register
3. Run a risk assessment
4. Apply the developer security checklist

This provides a basic security foundation for small teams.

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Project Structure

startup-security-kit
│
├ README.md
├ README.ja.md
│
├ docs
│
│  ├ en
│  │
│  │  ├ isms-lite
│  │  │   ├ security-policy.md
│  │  │   ├ asset-register.md
│  │  │   ├ risk-assessment.md
│  │  │   ├ incident-response.md
│  │  │   └ internal-audit.md
│  │  │
│  │  ├ checklists
│  │  │   └ developer-security-checklist.md
│  │  │
│  │  └ secure-backend-patterns
│  │      ├ jwt-authentication.md
│  │      ├ rbac-authorization.md
│  │      ├ api-security.md
│  │      ├ audit-logging.md
│  │      └ secret-management.md
│  │
│  └ ja
│      └ (Japanese translations)

English documents are the primary source. Japanese documents are translations.

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Roadmap

• ISMS Lite
• Developer Security Checklist
• Secure Backend Patterns
• Threat Modeling Examples
• Cloud Security Guide
• Incident Response Playbook

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Why This Project Exists

Most security frameworks target large enterprises.

However, startups and small teams face different challenges:

• limited resources
• small engineering teams
• lack of security specialists

Startup Security Kit provides practical security guidance designed for small teams.

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Claude Code Integration

1. Add Startup Security Kit

git submodule add https://github.com/st-hisatoshi-2973/startup-security-kit.git startup-security-kit
git commit -m "Add startup-security-kit as submodule"

2. Setup Claude skills

cp -r startup-security-kit/templates/claude .claude

3. Run

/ssk-security-review

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License

MIT