Developer Calculators

Developer utilities for encoding, formatting, and generating IDs — Base64, JSON, UUIDs, and timestamps.

4 calculators

Base64 Encoder / DecoderEncode text to Base64 or decode Base64 back to text.JSON FormatterFormat, validate, and minify JSON — pretty-print or compress in one click.Timestamp ConverterConvert a Unix timestamp to a readable date, or pick a date to get its timestamp.UUID GeneratorGenerate one or many random v4 UUIDs, each with its own copy button.

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 — so the only thing in your clipboard is the output you asked for.

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 — reach for real encryption if confidentiality is what you need. 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, which makes it safe to run on a live payload you intend to re-send. 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, turning a Unix timestamp (seconds or milliseconds since the 1970 epoch) into a human-readable UTC date, or giving you the Unix value in seconds and milliseconds for a date and time you pick. 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.

Start with the format you are wrestling with. If you need to ship binary-ish data through a text-only channel, use the Base64 tool. If a payload is malformed or unreadable, the JSON formatter both cleans it up and proves it is valid. If you need an identifier, the UUID generator is the fastest path to a safe random key. If you are debugging a log line or scheduling a job, the timestamp converter untangles the epoch math for you. 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.

Frequently asked questions

Is Base64 encoding the same as encryption?

No. Base64 is encoding, not encryption — it only changes how data is represented so it can travel through text-only systems. Anyone who receives a Base64 string can decode it instantly, so it provides no confidentiality. Use it to transport data safely, not to hide it; for secrecy, use real encryption.

Does the JSON formatter change my data?

No. Formatting only changes whitespace — it pretty-prints with a consistent two-space indent or minifies to a single line. The actual values in your JSON are never altered. If the input is not valid JSON, the formatter reports the error and shows nothing, so a successful output also confirms the data is valid.

Are the generated UUIDs truly unique?

The UUID generator creates version-4 identifiers using your browser's cryptographic random source, which makes collisions astronomically unlikely for any practical use. They are not registered or coordinated with any central authority, which is exactly why they are safe to mint locally for primary keys, request IDs, and correlation tokens without a round trip to a server.

Why does my Unix timestamp show a different time than expected?

Unix time is always measured in UTC, so the same timestamp reads as a different local wall-clock time depending on the viewer's timezone. The timestamp converter shows the UTC date and the raw seconds and milliseconds so you can compare values across systems without timezone confusion. Convert to your local time only at the very end, for display.

Are these developer tools private?

Yes. Every tool on this page runs entirely in your browser. Nothing you type — tokens, JSON payloads, or IDs — is uploaded, stored, or sent anywhere. You can paste sensitive data without it leaving your device, and the tools are free with no sign-up required.