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Free Developer Tools

Fast, private utilities for everyday development work — compare code, inspect JWTs, test regular expressions and decode cron schedules. Everything runs in your browser, so nothing you paste ever leaves your device.

Runs 100% in your browser No sign-up 6 tools and growing

No developer tool matches that search yet. Try the free tools directory.

What’s new

  • Code Diff Checker — Launched with split and unified views, word-level changes and patch export.
  • Cron Expression Parser — Launched with plain-English descriptions, presets and next-run preview.
  • JSON Diff — Launched with path-level diff report and ignore-array-order option.
  • JWT Decoder — Launched with claim timeline and HS256/384/512 signature verification.
  • Regex Tester — Launched with live highlighting, capture groups, replace preview and timeout protection.
  • Unix Timestamp Converter — Launched with auto unit detection, timezone conversion and live epoch clock.

More developer utilities

Formatters, encoders and lookups from the ProWebLook free tools directory.

Developer tools built for privacy and speed

Most online developer utilities send whatever you paste to a server. That is a problem when the input is a production JWT, a customer’s API response or proprietary source code. Every tool on this page is a static page that does its work with JavaScript in your browser: there is no upload step, no account and no rate limit, and the page keeps working if your connection drops after it loads.

Each tool focuses on one job and does it well: a code diff checker with syntax highlighting and patch export, a structural JSON diff that reports changes by path, a JWT decoder with signature verification, a regex tester with capture groups, a cron expression parser and a Unix timestamp converter. New tools are added regularly.

When a job needs live data — checking that a phone number is reachable, that an email mailbox exists or where an IP address is located — the ProWebLook API Playground lets you try the APIs from the same browser.

Frequently asked questions

Are these developer tools really free?
Yes. Every tool on this page is free, needs no account and has no usage limit, because the work happens in your own browser rather than on our servers.
Is my code or data uploaded?
No. Code, JSON, tokens and timestamps are processed locally with JavaScript. Some tools remember your last input or settings in your browser’s local storage so they survive a reload; clearing site data removes it.
How is this different from the ProWebLook /tools directory?
The free tools directory covers general utilities such as image converters, hash generators and DNS lookups. Developer Tools focuses on workflow tools for programmers — diffing, debugging tokens, testing patterns and scheduling — and links to the directory for the rest.
How often are new tools added?
New tools ship regularly. The “What’s new” list on this page shows every launch and notable update, and each tool page shows when it was last updated.

Need live data, not just formatting?

ProWebLook APIs validate phone numbers, check WhatsApp accounts, verify emails and geolocate IPs. Try every endpoint in the browser, then grab a free API key.

Open API Playground