5 free dev tools I built — no signup, no ads (most run entirely in your browser)

코딩나우(하늘아래) — Tue, 02 Jun 2026 03:41:17 +0000

I got tired of "free" online dev tools that bury you in ads, make you sign up, or quietly upload your data to a server just to format some JSON or resize an image. So over the last while I built a handful of small, single-purpose tools that fix that: no signup, no ads, and the web ones do everything in your browser — nothing is uploaded.

Sharing them here in case they're useful, and I'd genuinely love feedback on edge cases. I'm the author of all of these.

Web tools (100% client-side — your data never leaves the tab)

JSON Formatter & Validator → https://www.coding-now.com/en/json-formatter Pretty-print (2/4/tab) or minify, with a collapsible color-coded tree view. The part I use most: when JSON is invalid it points to the exact line:column of the error instead of a vague "unexpected token." Safe to paste API responses with tokens in them, since nothing is uploaded.
Image Format Converter (PNG · JPEG · WebP) → https://www.coding-now.com/en/image-converter Drag an image, pick a format, tweak quality, download. Handy for shrinking PNG screenshots to WebP, or flattening transparency before a JPEG export — all in the canvas, no upload.
Audio Cutter (trim to lossless WAV) → https://www.coding-now.com/en/audio-cutter Drop an MP3/WAV/M4A/OGG/FLAC, drag a region on the waveform, preview it, and export just that slice as WAV. Great for grabbing a clip without firing up an editor.
QR Code Generator (text · URL · WiFi · vCard + logo) → https://www.coding-now.com/en/qrcode Beyond plain URLs: generate WiFi QR codes (guests scan to join) and vCard contact QR codes, drop a logo in the center, and download PNG or SVG (the SVG embeds the logo too).

Bonus — a tiny desktop one

SnapLaunch (Windows) → https://www.coding-now.com/en/snaplaunch A portable tool that adds your favorite apps to the right-click menu of the Windows desktop/folders. No admin rights, single EXE. (This one's a native app, not a web tool — including it for completeness.)

Common thread: each is small, free, and respects your data — the web ones are a single static HTML file with zero dependencies. If you find a bug or a missing feature (especially in the JSON validator's error positions), I'd really appreciate hearing it in the comments.

DEV Community: 코딩나우(하늘아래)

5 free dev tools I built — no signup, no ads (most run entirely in your browser)