DEB II platform is a new language independent development platform for lexicographic tools based on the client/server architecture. It uses web Mozilla Development Platform for building special interface modules allowing to build the resulting lexicographic application such as a dictionary writing system from several components. The DEB II consists of a dictionary browser and editor for more XML dictionaries, an integrated Czech morphological analyzer and can cooperate with other applications such as corpus manager Manatee/Bonito and Word Sketch Engine or a geographical information system GRASS (used for building a Czech onomastic dictionary). The properties and assets of the DEB II platform will be presented as one of its current applications, the tool named PRALED, which is designed for preparation of the new Czech Lexical Database in the Institute of Czech Language in Prague.