10 Free Browser Tools Every Developer Should Bookmark (No Install, No Account)

Fateh R. — Sat, 25 Apr 2026 15:07:22 +0000

As developers, we install tools constantly — extensions, CLIs, npm packages, desktop apps. But half the time you just need something quick: format a JSON blob, generate a strong password, convert an image, test a regex. You don't need a full app for that.

Here are 10 browser-based tools I keep coming back to. They all run entirely client-side — meaning nothing ever leaves your machine. No accounts, no tracking, no ads.

1. JSON Formatter & Validator

Paste messy JSON and it instantly formats, indents, and validates it. Highlights syntax errors inline and lets you collapse deeply nested objects. It handles large payloads without choking, which most online formatters fail at.

I use this constantly when debugging API responses in the terminal — copy the raw string, paste, immediately readable.

→ JSON Formatter & Validator

2. Regex Tester

Write and test regular expressions with live match highlighting as you type. Supports all standard JS regex flags (g, i, m, s, u). Shows match groups separately, which saves a ton of back-and-forth when building complex patterns.

Useful for: input validation, log parsing, string extraction in scripts.

3. Password Generator

Configurable length (up to 128 chars), toggle uppercase, lowercase, numbers, symbols. Generates cryptographically random passwords entirely in-browser using the Web Crypto API. No network call, no server logging.

Much more trustworthy than most online generators where you have no idea what happens server-side.

4. Image Converter (WebP ↔ PNG ↔ JPG)

Drag an image, pick output format, download. The conversion runs on a <canvas> element in your browser — no upload to any server, no size limits imposed by server costs. Handles bulk files too.

Especially useful when you need WebP for web performance but your design tool only exports PNG.

5. Hash Generator

MD5, SHA-1, SHA-256, SHA-512 — all computed locally via the Web Crypto API. Useful for generating checksums, verifying file integrity, quick testing of hash-based logic, or sanity-checking that your backend hashing is working right.

6. QR Code Generator

Type any URL or text, get a scannable QR code instantly. Downloadable as PNG. No watermarks, no tracking pixels, no sign-up wall.

7. URL Encoder/Decoder

Encodes and decodes URL-encoded strings in one click. The kind of micro-tool you reach for when you're staring at a mangled query string in an API response and need to see what it actually says.

8. Word & Character Counter

Real-time word count, character count, sentence count, reading time estimate. Useful for hitting character limits on social platforms, checking SEO meta descriptions, or keeping API payloads under size thresholds.

9. Markdown to HTML Converter

Paste Markdown, get clean HTML output. Useful for quickly previewing documentation, converting README content for use elsewhere, or generating HTML snippets without spinning up a local dev server.

10. Color Converter

Convert between HEX, RGB, HSL, and HSB color formats instantly. Useful when you're switching between Figma (HSL), CSS (HEX/RGB), and design tokens (often HSL or RGB).

Why client-side matters

Most online tools silently send your input to a server. That's usually fine for public data — but when you're pasting API keys, internal JSON payloads, proprietary code snippets, or anything sensitive, you want to know your data isn't being logged somewhere.

Client-side tools eliminate that risk entirely. Everything stays in your browser tab.

The full collection

All 10 of these (plus a few more) are available at 3STF Tools — 23 free browser tools in total, organized by category: Text & Writing, Image & File, Developer, SEO, and Security.

No accounts required. No ads. No tracking. Just tools.

What browser tools do you keep bookmarked? Drop them in the comments — always looking for more.

DEV Community: Fateh R.