Hash

Compute a cryptographic hash (digest) of text, for checksums, cache keys or comparing values. The text is hashed as UTF-8.

Base64

Encode text as Base64, or decode Base64 back to text. Used in data URLs, HTTP Basic authentication, JWTs and email attachments.

URL encode / decode

Percent-encode text so it can go safely in a URL query string, or decode an encoded string back to readable text.

Form encoding (application/x-www-form-urlencoded): spaces become +.

Hex

Convert text to its UTF-8 bytes in hexadecimal, or hex bytes back to text. Handy for inspecting encodings and binary data.

XML escape / unescape

Replace the characters that have a special meaning in XML and HTML with entities, or turn entities back into characters.

Escapes & < > " '. Unescape also handles numeric references like A and A.

Case converter

Convert identifiers between naming conventions: camelCase, snake_case, kebab-case, CONSTANT_CASE and more.

Converts as you type. Each line is converted separately, so you can paste a list of names.

Lines → List

Turn a column of values (one per line) into a single delimited list, for example for an SQL IN clause or an array literal.

Split

Split text into parts on a delimiter or a regular expression and see every part with its index.

Substring

Extract part of a text by character position, counting from 0.

Negative indexes count from the end: start -3 gives the last 3 characters.

Transform

Apply a quick clean-up to text: sort or deduplicate lines, trim or remove whitespace, or reverse it.

Stats

Count characters, Unicode code points, UTF-8 bytes, words and lines. Useful to check length limits of fields and messages.

Regex tester

Test a Java regular expression against your text as you type: matches are highlighted, with their position and capture groups. Optionally try a replacement.

Java syntax (java.util.regex), as used by String.matches, Pattern and Spring. In the replacement, $1 or ${name} insert a group.

UUID generator

Generate universally unique identifiers (UUIDs), one or up to 100 at a time.

v7 UUIDs start with a timestamp, so they sort by creation time: a good choice for database keys.

Password generator

Generate a strong random password with a cryptographically secure generator. It is never cached.

The password contains at least one character of each selected type.

Random string

Generate a random string of the chosen length and characters, for tokens, test data or identifiers.

Java POJO from CSV

Paste a CSV header and get a Java field for every column, with a guessed type. Add a few data rows under the header and the types are taken from the values.

Values: true/false/yes/no → Boolean, whole numbers → BigInteger, decimals → BigDecimal, 2026-01-01 → LocalDate, 2026-01-01 09:30 → LocalDateTime, anything else → String. Wrapper types are used because an empty cell means null; choose primitive types when every row has a value.

Timestamp converter

Convert a Unix timestamp (epoch) to a readable date and back. Paste seconds, milliseconds or a date like 2026-01-01T09:00:00Z: the unit is recognised automatically.

How it works

What is a Unix timestamp? It counts the seconds since 1 January 1970 at 00:00 UTC (the "epoch"), the same number everywhere in the world. Time zones only matter when you turn it into a date.

Seconds or milliseconds? Linux (date +%s), PHP and most databases use seconds (10 digits today). Java (System.currentTimeMillis()) and JavaScript (Date.now()) use milliseconds (13 digits). Microseconds have 16 digits, nanoseconds 19.

Good to know: Unix time ignores leap seconds, and 32-bit systems that store it as a signed int overflow on 19 January 2038 at 03:14:07 UTC (the "year 2038 problem"). Use 64-bit values (long in Java).

Cron expression

Build a schedule and get the cron expression for Linux crontab, Spring (Java @Scheduled) and Quartz, with the next run times.

The end hour is not included: from 9 to 17 means the last run is before 17:00, so nothing runs in the evening or at night.

Linux has 5 fields and no seconds. Spring puts seconds in front (6 fields). Quartz also starts with seconds, accepts an optional year and needs ? in day of month or day of week. Spring and Quartz days are written as names (MON-SUN) because the two number them differently (in Quartz 1 = Sunday).