Every developer keeps a handful of small utilities within arm’s reach — the ones you reach for a dozen times a day without thinking. This is a curated checklist of ten free, browser-based tools that cover the most common day-to-day tasks. All of them run locally in your browser, so nothing you paste is uploaded to a server.
1. JSON formatter
Machine-generated JSON is often crammed into one unreadable line. A JSON formatter beautifies it into a clear indented structure, minifies it back down for transport, and validates the syntax so you catch a stray comma before your code does.
2. Base64 encoder / decoder
When you need to carry binary or special characters through a text-only channel — email, JSON, data URIs, JWTs — Base64 is the answer. A good Base64 tool handles full UTF-8 (so Chinese, Japanese and emoji survive the round trip) and offers a URL-safe mode.
3. Hash generator
Verifying a downloaded file, comparing two blobs of text, or learning how hashing works? A hash generator that uses the browser’s native Web Crypto API gives you SHA-256 and SHA-512 instantly, without sending your input anywhere.
4. UUID generator
Need a batch of unique identifiers for database keys or test data? A UUID generator produces RFC 4122 v4 IDs using a cryptographic random source — copy a hundred at once.
5. Unix timestamp converter
Logs and APIs love storing time as a Unix timestamp, which humans can’t read at a glance. A timestamp converter turns those numbers into local and UTC dates (and back) and shows a live current timestamp.
6. Word counter
Whether you’re writing an essay, tuning an SEO article, or squeezing a post under a character limit, a word counter gives you words, characters, sentences, paragraphs and reading time as you type.
7. Case converter
Renaming variables or tidying titles? A case converter switches between camelCase, snake_case, kebab-case, Title Case and more in one click.
8. URL encoder / decoder
Special characters and non-ASCII text break URLs. A URL encoder percent-encodes query parameters correctly and decodes the cryptic %XX strings you copy from an address bar.
9. A diff / text-compare tool
When two files “look identical” but behave differently, a diff tool highlights the exact characters that changed. (Coming soon to our toolbox.)
10. A regular-expression tester
Regex is powerful and easy to get wrong. A live tester that highlights matches as you type turns trial-and-error into something you can actually reason about. (Coming soon.)
How to choose a good online tool
Not all “free” tools are equal. A few things worth checking:
- Does it run locally? If a tool processes your data in the browser (like the ones above), your input never leaves your device — important for anything sensitive.
- Is it fast? Static, CDN-served tools load instantly and respond without a network round trip.
- Is it honest about its limits? For example, a hash tool that skips MD5 because it’s insecure is telling you something useful.
Bookmark the handful you use most, and you’ll shave a surprising amount of friction off your day. You can find all of the tools above, free and privacy-first, right here on DevToolbox.