Free Developer Formatting & Conversion Tools
JSON formatting, Base64, URL encoding, Unix timestamps, and regex testing — five tools, one page, no sign-up.
Runs 100% in your browser•Nothing is uploaded to a server•Free forever
Input
Input
Input
Epoch → Date
Date → Epoch
Pattern
Highlighted matches
Matches & capture groups
About DevBox Kit
DevBox Kit bundles five everyday developer utilities into a single page: a JSON formatter and validator with precise syntax-error locations, a two-way Base64 encoder/decoder, a two-way URL encoder/decoder, a Unix timestamp converter that shows both local and UTC time, and a regex tester with live match highlighting and capture groups.
Everything runs entirely client-side in your browser — nothing you paste in is ever uploaded to a server, so there's no wait and nothing to worry about privacy-wise. Use it for debugging API responses, decoding tokens, sanity-checking query strings, converting timestamps from logs, or testing a regular expression before you commit to it.
Prefer a dedicated page for a single tool? Each one also lives on its own: JSON Formatter, Base64 Encode / Decode, URL Encoder / Decoder, Unix Timestamp Converter, and Regex Tester.
Learn more about developer tools
JSON formatting guide
JSON syntax rules, the most common JSON errors, why JSON.parse messages are so cryptic, and when to minify vs. pretty-print.
Base64 and URL encoding explained
What Base64 actually does (it's not encryption), common real-world use cases, and when you need URL/percent-encoding instead.
Unix timestamp guide
Epoch time explained, the Y2038 problem, how to tell seconds from milliseconds, and timezone/UTC conversion gotchas.
Regex cheat sheet
Practical patterns, flags, and gotchas — anchors, character classes, greedy vs. lazy quantifiers, and catastrophic backtracking.