Dev Toolbox
Everyday security helpers for code and design reviews. Tokens, headers and code never leave your browser.
- JWT decoder and linter: alg none, missing exp, weak claims, sensitive data
- CSP evaluator and builder: unsafe-inline, bypassable hosts, strict-dynamic
- Security headers and cookie checker with A+ to F grade
- Base64, URL, HTML, hex encoders and SHA hashes
- Secrets scanner for AWS, GitHub, Slack, Stripe keys and private keys
More free security tools
- Threat Modeling: Model components, data flows and trust boundaries, generate STRIDE threats with mitigations, rate risk and export a Markdown report with a Mermaid diagram.
- Review Checklists: Run secure code reviews with OWASP Top 10:2025, API Security Top 10 and ASVS 5.0 checklists, record pass/fail with notes and paste the summary into your PR.
- Dependencies & CI: Check package-lock, yarn.lock, requirements.txt, pom.xml, go.sum and more against OSV.dev, and generate GitHub Actions for CodeQL, Dependabot, gitleaks and Trivy.
- Data Lab: Chain 100+ operations into recipes: Base64, hex, URL, AES-GCM, HMAC, PBKDF2, MD5/SHA, gzip, XOR brute force, IOC extraction and defanging, with Magic auto-detect.
- PKI Tools: Decode and lint X.509 certificates, chains, CSRs and CRLs, generate CSRs and keys, match keys to certificates, convert PEM/DER/P7B/JWK. Nothing is uploaded.
- AI Skill Scanner: Scan SKILL.md files, agent instructions, MCP server configs and Claude Code hooks for prompt injection, data exfiltration, hidden Unicode and dangerous commands.
- Website Recon: Passive recon for a domain: DNS records, SPF, DMARC, DKIM, CAA, DNSSEC, certificate transparency subdomains, RDAP registration, HSTS preload and archive history.
Source code on GitHub (open source).