Every developer has a set of go-to utilities they use daily — formatting JSON, generating test passwords, encoding strings, validating regex patterns. The best ones run in your browser: nothing to install, always available, and they don't send your data anywhere.
JSON Formatter and Validator
Unreadable minified JSON is the bane of every debugging session. A JSON formatter takes one-line blobs and turns them into properly indented, color-coded output. It also validates syntax — so if your API response is silently broken, you'll know immediately.
When you need it: Debugging API responses, reading config files, reviewing webhook payloads, cleaning up data exports.
Tip: A good formatter also catches common JSON mistakes — trailing commas, unquoted keys, single quotes instead of double quotes — that many JSON parsers silently reject.
Password Generator
Generating strong, truly random passwords is something computers do much better than humans. A password generator lets you set length, include uppercase, lowercase, numbers, and symbols, and copy to clipboard instantly.
When you need it: Creating credentials for new accounts, generating API keys in formats that aren't auto-generated, setting up test environment passwords, creating secure tokens for configs.
Security note: The best tools generate passwords client-side in your browser — nothing is sent to a server. Verify this before using any tool for sensitive credentials.
QR Code Generator
QR codes are everywhere — WiFi credentials on office walls, product packaging, business cards, event tickets. A QR code generator creates a scannable code from any URL, text, email, or phone number in seconds.
Common uses for developers: Deep links for mobile app testing, sharing localhost tunnels (ngrok URLs), encoding connection strings for IoT devices, generating test codes for scanner integrations.
Base64 Encoder / Decoder
Base64 encoding is ubiquitous in web development — API authentication headers, data URIs for inline images, JWT payloads, email attachments. Being able to encode/decode without leaving your terminal or browser saves time constantly.
Word Counter and Character Counter
More useful than it sounds. A word counter is essential when working with:
- Meta descriptions (155–160 character limit for SEO)
- Twitter / X posts (280 characters)
- SMS content (160 characters per segment)
- Database varchar fields (knowing if your input exceeds column length)
- AI prompt engineering (token estimation — roughly 4 characters per token)
Percentage and Unit Calculators
Developers doing quick calculations during estimation, pricing, or data analysis benefit from a percentage calculator that handles increase/decrease, ratio, and compound changes. Much faster than writing a throwaway script.
Why Browser-Based Tools Beat Downloading Scripts
- No installation: No npm package, no Python dependency hell, no version conflicts.
- Shareable: Send a link to a colleague — they immediately have the same tool.
- Cross-platform: Works identically on Mac, Windows, Linux, and any OS.
- No maintenance: No security updates to apply, no breaking changes to deal with.
The one case where local tools win: processing large files (10 MB+ JSON, binary data) where browser memory limits matter, or highly sensitive data you'd never send anywhere.
All Free Developer Tools in One Place
Browse the full free tools directory — JSON formatter, password generator, QR code creator, word counter, percentage calculator, and 20+ more utilities. All free, all in your browser, no sign-up.