This page lists various tools related to internationalization that may be helpful. They are not maintained or owned by the W3C, and the links are provided with no guarrantees.
A Perl script for character normalization.
Unicode code converter
Browser-based app. Converts between characters, Unicode code point numbers, UTF-8 and UTF-16 code units in hex, Numeric Character References (hex and decimal), percent-encoded text, and other character escape formats.
Browser-based app. UniView is a Unicode character viewer/picker that displays characters from a selected range or search pattern, provides information about them, and allows you to assemble strings from them like in a character map. You can also create customizable lists of characters for pasting into documents. UniView supports the latest version of the Unicode Standard, including the supplementary planes as well as the BMP. Characters are displayed as graphics by default, but you can also display them using an installed font.
Browser-based app. Allows you to see how Unicode characters are represented by bytes in various legacy encodings, and vice versa. You can customise the encodings. The algorithms used are based on those described in the Encoding specification, and thus describe the behaviour you can expect from web browsers.
List characters tool
Browser-based app. Analyses the characters in text that you paste into the large box at the top, and produces a list of what characters were used, grouped by Unicode block.
IANA Language Subtag Registry search tool
Browser-based app. Look for subtags by searching on the descriptions in the registry. Look up subtags and sequences of subtags. List the various types of tag currently available. Runs on the most up-to-date version of the registry.
W3C Internationalization Checker
Performs various tests on a Web Page to determine its level of internationalisation-friendliness. It also lists key internationalization settings related to character encoding, language declarations, text direction and class/id names. This information includes HTTP headers, which can be particularly useful for troubleshooting problems.
Counter styles converter
Browser-based app. Allows you to convert ASCII numbers into other representations that can be used to create counters for ordered lists, headings, figures, etc. It uses the algorithms described by CSS3 Counter Styles and Predefined Counter Styles.
Unicode character pickers
Browser-based app. The pickers display the characters that are used for a range of languages, and allow you to compose one or more words by clicking on characters. The list of scripts supported includes Arabic, Armenian, Bengali, Devanagari, Egyptian Hieroglyphs, Ethiopic, Gujarati, Gurmukhi, Hebrew, Khmer, IPA, Lao, Latin, Lisu, Malayalam, Myanmar, Runic, Tamil, Thai, Tibetan, Tifinagh, Tłįchǫ (Dogrib), Urdu and Vietnamese, and more are added from time to time. Pickers are particularly useful for people not familiar with a script, but the optimisations, conversion tools, etc, can also be helpful to more experienced users.