Developer Calculators

Developer work is full of small, repetitive transformations that are easy to get wrong by hand. Base64-encoding a token, pretty-printing an API response, minting a UUID for a database row, or converting a Unix timestamp into a readable date are all things you might do a dozen times a day. The developer calculators on this page do those jobs instantly, in your browser, with no install and no upload. **Base64** is the workhorse of text-safe binary transport. It turns arbitrary bytes into a limited alphabet of letters, digits, `+`, `/`, and `=` so the data can travel through systems that only understand text — email, JSON, URL parameters, and basic-auth headers. This tool encodes plain text to Base64 and decodes Base64 back to text, with proper UTF-8 handling so accents, Chinese characters, and emojis survive the round trip. Note that Base64 is *encoding*, not *encryption*: anyone can decode it, so never use it to hide a secret. **JSON** is the lingua franca of APIs, and it is painfully easy to hand-edit into something invalid. The JSON formatter parses your input and, if it is valid, pretty-prints it with a consistent two-space indent or minifies it to a single compact line. If the input is not valid JSON, it tells you exactly what went wrong and shows nothing — so a successful output is, in effect, a validation pass. Formatting never changes your data, only the whitespace. **UUIDs** (universally unique identifiers) are the standard way to generate primary keys, request IDs, and correlation tokens without a central authority. The UUID generator creates version-4 identifiers using your browser's cryptographic random source, one at a time or in bulk, and gives every value its own copy button so you can grab exactly the one you need. Random v4 UUIDs also avoid leaking row counts or creation order the way sequential integers do. **Timestamps** are where off-by-timezone bugs are born. The timestamp converter goes both ways: turn a Unix timestamp (seconds or milliseconds since the 1970 epoch) into a human-readable UTC date, or pick a date and time and get its Unix value in seconds and milliseconds. Because Unix time is always UTC, the same number reads as different wall-clock times in different regions — keep that in mind when comparing values across systems. Every tool here runs entirely client-side. Nothing you type is uploaded or stored, which matters when you are pasting tokens, payloads, or IDs that should never leave your machine. Use them as often as you like; they are free and require no sign-up.