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 the policy generated live, and get a security rating. Runs client-side.
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. Runs client-side.
Category: securityCSP Hash Calculator
Generate SHA-256 hashes for inline scripts. Get ready-to-use CSP directives for your Content Security Policy. Runs client-side.
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. Runs client-side.
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. Runs client-side.
Category: devCron Expression Builder
Visual cron expression builder with interactive field selectors, presets, next execution preview, and crontab output. Runs client-side.
Category: devRegex Tester
Test regular expressions with real-time match highlighting, capture groups, replace mode, and common pattern presets. Runs in your browser.
Category: devUnix Timestamp to Date Converter
A Unix timestamp counts seconds since 1970-01-01 UTC. Convert one to a date and back, seconds or milliseconds, in 11 time zones — all in your browser.
Category: networkNginx Config Generator
Generate Nginx server blocks with upstream, QUIC/HTTP3, rate limiting, tarpit, OCSP stapling, and modern TLS. Runs client-side.
Category: networkIP / Subnet Calculator
IPv4 and IPv6 subnet calculator with CIDR notation, VLSM planner, range-to-CIDR converter, and reverse DNS. Runs client-side.
Modbus Frame Builder
Build and decode Modbus RTU/TCP/ASCII frames with CRC-16/LRC calculation, register interpretation, and byte visualization. Runs client-side.
String-Pool Packer
Compare a pointer table vs a packed, tail-merged string pool with uint16 offsets. Paste strings and watch the bytes saved. Runs client-side.
Category: mikrotikWireGuard Config Generator
Generate MikroTik RouterOS WireGuard VPN configs with dual-stack IPv4/IPv6, firewall rules, NAT, peers, and client files. Runs client-side.
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.