Private tools for people who run servers.
Fast, private tools for DevOps and security engineers. Everything runs in your browser — nothing is uploaded.
🔒 Strict Content-Security-Policy — these pages can't send your data anywhere
All tools
- Cron Expression Explainer Translate any crontab expression into plain English and see the next run times. Supports ranges, steps, lists, month/day names and @macros.
- Chmod Calculator Convert Linux file permissions between octal (755) and symbolic (rwxr-xr-x). Includes setuid, setgid and sticky bits.
- CIDR / Subnet Calculator Calculate network address, broadcast, netmask, wildcard mask and usable host range for any IPv4 CIDR block.
- JWT Decoder Decode JSON Web Token header and payload, check expiry, and verify HS256/384/512 signatures — entirely in your browser.
- Unix Timestamp Converter Convert Unix epoch timestamps (seconds or milliseconds) to UTC and local time, and dates back to epoch.
- HTTP Status Codes Every common HTTP status code explained, with causes and how to fix them. Searchable reference.
- Port Lookup Find which service uses a TCP or UDP port, with security notes for exposing it to the internet.
- Base64 Encode / Decode Encode and decode Base64 and Base64URL with full UTF-8 support. Runs locally — safe for secrets and config.
- YAML ⇄ JSON Converter Convert Kubernetes manifests, Compose files and CI configs between YAML and JSON, with clear error line numbers.
- Regex Tester Test regular expressions with live match highlighting and capture groups. Protected against catastrophic backtracking.
- PDF Tools Merge, split, compress, rotate and reorder PDFs, convert images to PDF and back, add page numbers or watermarks, and strip metadata. Files never leave your browser.
Why another tools site?
Most online converters post your input to a server. That's a problem when the input is a production JWT, a private certificate or an internal config file. Every tool here is plain JavaScript running in your browser, and the site sends a Content-Security-Policy header with connect-src 'self', so the page has no way to upload what you paste. Open DevTools → Network and check.