Toolkit for Engineer

22 developer tools in one side panel — JSON, timestamps, JWT, regex, diff, hashes, images. No tab switching, no uploads.

Every time a timestamp shows up in a log, you open a new tab and search for a converter. Every time an API response needs formatting, you paste company JSON into a site you have never heard of. Toolkit for Engineer moves those 22 jobs into the browser side panel, right beside the page you are already on. ■ DATA & FORMATS · JSON — parse, format, and explore a collapsible color tree. Escaped strings are unwrapped automatically. Build JSON from scratch, or compare two payloads structurally · XML — parse errors pinpointed, color tree view, builder, structural compare · Diff — compare two texts by line or by word, with added/removed counts · Base64 · URL encode/decode · Hashes (MD5, SHA-1/256/384/512) · Number base conversion · Text case conversion and counters ■ TIME & MATH · Time — convert Unix timestamps to dates and back. The unit (seconds, millis, micros, nanos) is detected from the digit count, and GMT, local, ISO 8601 and relative time are shown at once. Includes a live clock and period start/end timestamps · Calculator — keyboard input, floating-point noise corrected (0.1 + 0.2 = 0.3), and a saved history · Unit converter — length, area, mass, temperature, data size · Currency — convert with up-to-date exchange rates · Cron — read an expression and see the next runs ■ SECURITY & GENERATORS · JWT — header and payload decoded the moment you paste, with iat and exp shown as readable times and expiry flagged. The token is decoded locally and never sent anywhere · Regex — matches highlight as you type, flags toggle instantly, and ten ready-made presets cover email, URL, IPv4, UUID, hex color and more · Password generator · UUID v4 and ULID · QR codes · Color conversion (HEX/RGB/HSL) ■ IMAGES & MORE · Image — resize, compress, convert (WebP, AVIF, JPEG, PNG) and crop, all inside your browser with no upload · SVG — preview, optimize with SVGO, convert to PNG or a data URI · Environment Indicator — register domain rules and a colored bar marks production or staging pages, so you notice where you are before you click ■ EVERYDAY DETAILS · Search to jump straight to a tool, and pin the ones you use most as favorites · Reorder tools and hide the ones you never touch · A memo pad at the bottom of the panel — jot notes while you work, save them, or export as .txt · Dark, light, and system themes, plus a UI scale setting · English · 한국어 · 日本語 ■ PRIVACY Whatever you paste — JSON, tokens, text, images — is processed entirely inside your browser and is never uploaded. No accounts, no ads, no cross-site tracking. The extension makes two kinds of network request. The currency tool downloads a public exchange-rate table, and that request contains none of your data. Separately, anonymous usage statistics show which tools people actually use — these can be turned off at any time in Settings. What you type into the tools is never sent, either way. Install it, click the toolbar icon, and the side panel opens. Next time you meet a timestamp, convert it instead of searching for it.