Tools
Developer Tools
Browser-based utilities for web security and development. All calculations happen locally—no data is sent to any server.
privacy-first · 0 telemetry
Certificate Inspector
Decode PEM SSL/TLS certificates or fetch from a URL client-side. Inspect subject, issuer, validity, SANs, key usage, and security assessment.
Category: securityCSP Policy Builder
Build Content Security Policy headers interactively. Toggle directives, see real-time policy generation, and get security ratings for your CSP.
Category: securityEncrypt-then-MAC Envelope Visualizer
Seal a secret into an encrypt-then-MAC envelope, flip a byte, and watch the read verify the tag before decrypting — and fail closed on tampering.
Category: securityCSP Hash Calculator
Generate SHA-256 hashes for inline scripts. Get ready-to-use CSP directives for your Content Security Policy.
Category: securityHTTP Security Headers Analyzer
Analyze HTTP response headers for security best practices. Get a security score, recommendations, and detailed analysis for each header.
Category: securityPassword Generator
Generate strong passwords and passphrases using the Web Crypto API. Estimate entropy, crack time, and customize character sets — all client-side.
Category: securityOffline PIN Brute-Force Calculator
Estimate how long an offline GPU takes to brute-force a PIN through PBKDF2 — then toggle device binding and watch it become infeasible.
Category: devBase64 Encoder / Decoder
Encode and decode Base64, Base64URL, URL encoding, hex, and HTML entities. File support for images and documents. Runs client-side.
Category: devColor Contrast Checker
Check color contrast ratios for WCAG 2.2 AA and AAA compliance with APCA support, color blindness simulation, and auto-fix suggestions.
Category: devCron Expression Builder
Visual cron expression builder with interactive field selectors, common presets, next execution preview, crontab line output, and shareable links.
Category: devRegex Tester
Test regular expressions with real-time match highlighting, capture groups, replace mode, and common pattern presets. Runs in your browser.
Category: devTimestamp Converter
Convert Unix timestamps to human-readable dates and vice versa. Supports seconds, milliseconds, ISO 8601, RFC 2822, and timezone comparison.
Category: networkNginx Config Generator
Generate Nginx server blocks with upstream, QUIC/HTTP3, rate limiting, tarpit, OCSP stapling, Brotli, and modern TLS best practices.
Category: networkIP / Subnet Calculator
IPv4 and IPv6 subnet calculator with CIDR notation, VLSM planner, range-to-CIDR converter, reverse DNS, and bit boundary visualization.
Modbus Frame Builder
Build and decode Modbus RTU/TCP/ASCII frames with CRC-16/LRC calculation, register interpretation, response builder, and byte visualization.
String-Pool Packer
Compare a pointer table vs a packed, tail-merged string pool with uint16 offsets. Paste strings and watch dedup, tail-merge, and bytes saved.
Category: mikrotikWireGuard Config Generator
Generate complete MikroTik RouterOS WireGuard VPN configurations with dual-stack IPv4/IPv6, firewall rules, NAT, peers, and client config files.
About These Tools
All calculations happen in your browser. Your code never leaves your device.
No server round-trips. Results update as you type with zero latency.
View the source code on . Contributions welcome. GitHub.