ICU Message Editor
Visually build and test ICU Message Format patterns — plural, select, and more.
Live Preview
What is ICU Message Format?
ICU Message Format is the industry standard for internationalized messages that adapt to language rules. It handles pluralization (one item vs. many items), gender selection (he/she/they), and number/date formatting across different locales. This free visual editor lets you build, test, and debug ICU messages without memorizing the syntax.
How to Use the ICU Message Editor
- 1
Write your ICU message
Enter an ICU Message Format string in the editor. Use the syntax helpers to insert plural rules (｛count, plural, ...｝), select statements (｛gender, select, ...｝), or number/date formatting.
- 2
Set variable values
Adjust the variable inputs below the editor to test different values. Change the count to see plural forms update, or switch the gender variable to preview select branches.
- 3
Preview and copy the result
The live preview shows exactly how the message renders with your test values. Copy the ICU string to paste into your i18n locale files for production use.
Frequently Asked Questions
What is ICU Message Format used for?
ICU Message Format handles pluralization, gender selection, and locale-aware formatting in translated strings. It is supported by most i18n libraries including FormatJS, i18next, and Angular.
What does the # symbol mean in plural messages?
The # symbol is replaced with the actual numeric value at runtime. For example, in '# items', if count is 5, it renders as '5 items'.
Is my data processed on a server?
No. All parsing and preview happens locally in your browser. Nothing is sent to any server.