Beyond subnet math, we maintain a network of free, browser-based tools that solve everyday engineering and productivity problems. All free, all without signup, all built with the same engineer-first philosophy.
This page is a curated index of free, browser-based developer tools — calculators, converters, formatters, and utilities that solve real engineering problems without requiring a signup or a credit card. The tools are grouped by category: networking (subnet calculators, IP lookup, DNS utilities, bandwidth math), data conversion (base64, JSON, YAML, hex/binary, timestamp), text utilities (regex testers, diff viewers, lorem ipsum, case converters), media tools (image compressors, color pickers, gradient generators), and time and date (timezone converters, cron parsers, date arithmetic).
Every tool listed here follows the same principles: free to use, no signup required, calculations performed in the browser whenever possible. They are built by independent developers and small teams who believe useful tools should not be locked behind paywalls or aggressive upsells. The list is curated; tools that load nine ad units before the first input box do not make the cut.
If you build a free developer tool and want to be considered for this list, get in touch via the contact page. We add new tools when they meet the standard. If you came here looking for our own tools, they are linked from the homepage and the main navigation — start with the subnet calculator, the VLSM planner, the cloud-aware tool, or the Learn Center.
Every site listed here follows the same rules: free to use, no signup required, calculations performed in the browser whenever possible. They're built by independent developers and small teams who believe useful tools shouldn't be locked behind paywalls or pop-ups.
All external links open in a new tab and use rel="nofollow noopener" per web standards.