MessageFormat · Free Local Tool

Icu Message Validator

Check the ICU MessageFormat brackets, variables, Plural and Select branches, and list the rules and test data that are missing other.

No uploadsMobile-friendlyTheme support

What is the ICU MessageFormat validator?

Check the ICU MessageFormat brackets, variables, Plural and Select branches, and list the rules and test data that are missing other. ToolHub places the core computing entirely within the browser, allowing immediate use on both desktop and mobile devices, without the need to register an account or send content to the backend.

How to use this tool?

  1. Enter the data according to the field prompts and select the required processing method.
  2. Click "Process Now" to view the results, indicator summary and necessary error messages.
  3. After confirming that the content meets actual needs, you can copy the results or download them into files for further use.

Suitable use cases

Translation string QA, Plural copywriting design, Localization CI and message template maintenance. All processing is completed in the current page, which is especially suitable for workflows that do not want to post internal data to remote services.

Interpretation of results and precautions

Currently focusing on the common ICU Message syntax, complex nested formats should then be verified by the target framework compiler. Tools will validate basic input formats and provide readable error messages, but production environments should still be reconfirmed against source specifications, business rules, or professional requirements.

Browser and device support

Icu Message Validator supports current Chrome, Edge, Firefox, and Safari releases. Mobile and desktop layouts use the same validation rules documented on this page.

Frequently Asked Questions

Will the ICU MessageFormat validator upload data to the server?
No. Tool functions are executed directly within the current browser tab, and input and generated results will not be uploaded or saved by ToolHub.
What use cases is the ICU MessageFormat validator suitable for?
Translation string QA, Plural copywriting design, Localization CI and message template maintenance
Do I need to install software before using the ICU MessageFormat validator?
No need. Use a desktop or mobile browser that supports modern JavaScript, and no account is required.
What are the limitations of this tool?
Currently focusing on the common ICU Message syntax, complex nested formats should then be verified by the target framework compiler.
Is manual inspection required after the results are generated?
Needed. Tools can assist with calculations, conversions, or formatting, but before going online, importing data, or making business decisions, the results should still be reviewed according to actual specifications.

Icu Message Validator: inputs, output, and reproducible example

Use the free Icu Message Validator online. Fast, private, mobile-friendly, and processed directly in your browser.

What this page actually processes

FieldControlDefault exampleValidation role
Plural LocaleTextzh-TWPlural Locale is read by the browser as a text value before the tool runs.
ICU MessageMultiline text{name} has {count, plural, =0 {no new notifications} one {# then new notifications} other {# then new notifications}}.ICU Message is read by the browser as a multiline text value before the tool runs.
Test variables JSONMultiline text{"name":"Xiao Ming","count":3}Test variables JSON is read by the browser as a multiline text value before the tool runs.

Reproduce the built-in example

Start with Plural Locale = zh-TW; ICU Message = {name} has {count, plural, =0 {no new notifications} one {# then new notifications} other {# then new notifications}}.; Test variables JSON = {"name":"Xiao Ming","count":3}, then run Icu Message Validator. Change one input at a time so the effect on the result remains traceable.

After validating plural locale, icu message, test variables json, the page displays its result in the output workspace and enables the relevant copy or download action.

When to use it and how to interpret the result

Translation string QA, Plural copywriting design, Localization CI and message template maintenance. All processing is completed in the current page, which is especially suitable for workflows that do not want to post internal data to remote services.

Limits and checks before use

Currently focusing on the common ICU Message syntax, complex nested formats should then be verified by the target framework compiler. Tools will validate basic input formats and provide readable error messages, but production environments should still be reconfirmed against source specifications, business rules, or professional requirements.

Page verification record

Controls inspected3 documented inputsResult pathValidate → process → review → copy/downloadLast content review2026-09-02