Do these utilities upload my data?

No. Regex, JWT, diff, and related tools process input in your browser. Nothing is sent to AllOneTools servers unless a specific tool documents an optional network call.

Are JWT signatures verified in the browser?

The JWT debugger can verify HMAC secrets locally. Asymmetric verification depends on the page implementation; check the tool notes for supported algorithms.

Free online developer utilities — regex, JWT, UUID, diff & more

A collection of privacy-first browser tools for everyday developer tasks. Every utility runs entirely in your browser — no server uploads, no accounts, no tracking. Bookmark this hub for fast access to regex testing, JWT decoding, cron scheduling, UUID generation, text diffing, password creation, and more.

Small, focused tools for debugging and chores: patterns, schedules, tokens, identifiers, time, text diffs, secrets hygiene, and quick encoding. Pair these with the full dev-tools index and format-specific hubs (JSON, HTML, XML, JS).

All utilities on this hub

Base64 encode / decode

Standard and URL-safe Base64; text and small file drops — client-side only.

Open tool → Cron Expression Builder & Generator

Free online cron builder: translate schedules to plain English, validate syntax, and preview next runs.

Open tool → Diff Checker

Online diff checker tool — compare CSV, XML exports, or text side-by-side with line-level highlighting.

Open tool → Discord Timestamp Converter

Generate Discord dynamic t: timestamps from Unix epoch — copy default, full, relative, time, or date styles.

Open tool → JWT Debugger

Decode, inspect, and verify JSON Web Tokens with HMAC signature checking.

Open tool → Markdown to HTML

MD → HTML with email-safe mode, optional changelog wrap, scripts stripped in-browser.

Open tool → Number to Words Converter

Number to words online, A1Z26 letter–number cipher, and phone keypad vanity mapping — all in your browser.

Open tool → Password Generator

Generate strong, random passwords and passphrases with a live entropy score.

Open tool → QR code generator

Create QR codes for URLs, text, Wi‑Fi, and vCard — PNG download, error correction, colors.

Open tool → Regex Tester

Regex tester online with Go RE2, bash/grep, sed -E, Perl, and C# flavor guides — live matches in your browser.

Open tool → Timestamp Converter

Convert between Unix epoch timestamps and human-readable dates across time zones.

Open tool → UUID / ULID / NanoID Generator

Generate secure UUID v4, ULID, and NanoID identifiers in bulk.

Open tool →

Looking for AI pricing math? Use the AI & LLM tools hub .