Filigree architecture is a modern term given to a phase in the history of Australian architecture. The phase was an embellishment of the "Australian verandah tradition", where the verandah evolved from its functional usages to become highly ornamental.

The filigree style was a vernacular tradition of buildings possessing prominent verandahs that screened the facade, cloaking the exterior in an ornamental veil that obscured the rest of building. On filigree style buildings, the verandah was the dominant visual element. The term "filigree" refers to the intricate texture of this verandah screen, which was often perforated to let air and light pass through, creating dazzling displays of shadows.

In the Victorian era, the style exploded into popularity. Double- and triple-storey verandahs lined the main streets, with some rare examples reaching up to four storeys. Victorian Filigree style verandahs were made almost exclusively from cast iron, and their delicate appearance gave rise to the term cast iron lacework. In the Federation era, the style evolved into the Federation Filigree style, when timber eclipsed cast iron as the predominant material of choice and the shape and form of the verandah became more novel.

The style was mainly popularised by speculative builders, but it did not have a class consciousness, being used both on humble workers cottage developments and grand mansions, as well as by prominent commercial architects such as Richard Gailey and Andrea Stombuco. Neither was it reserved for a single setting, being used on domestic, commercial and governmental buildings, becoming particularly well associated with Australian terrace houses and pub verandahs.

These strong associations have led to the filigree style being "regarded as distinctly Australian." While ornamental cast iron verandahs can be found elsewhere in the world, Australia possesses a unique interpretation of the design and form of this style, as well as a prevalence unseen elsewhere.

"Filigree" was first proposed as a style descriptor by architectural historian Richard Apperly, and was popularised in A Pictorial Guide to Identifying Australian Architecture: Styles and Terms from 1788 to the Present (1989) by Richard Apperly, Robert Irving & Peter Reynolds. The book attempted to establish a series of guidelines governing Australian architectural styles, splitting them into six distinct, chronological eras: Old Colonial, Victorian, Federation, Inter-War, Post-War and late-twentieth-century.

A particular focus of Apperly, Irving, & Reynolds was recognising unique, Australian trends that had so far been unrecognised in academia. They coined the term "filigree" to describe the prevalence of buildings possessing prominent verandah and balcony structures that dominate the facade, hiding the building's external walls behind an intricately textured verandah screen that subsumed the building. The term "filigree" refers to the intricate texture of the balustrades, columns, brackets and friezes that make up that verandah screen, which was often perforated to let air and light pass through. This lacy, filigree screen was designed to stand dominant of the main building, creating an in-between space that was both public and private.

Apperly, Irving, & Reynolds divided Filigree architecture into two main phases. Victorian Filigree described architecture with a visually dominant verandah or balcony constructed during the Victorian era (c. 1840 – c. 1900). The primary verandah construction material in this era was cast iron, often referred to as cast iron lacework. Federation Filigree describes the continuation of this verandah tradition into the Federation era (c. 1890 – c. 1920. In this period, cast iron (though still in usage) was eclipsed by the demand for novel, naturalised materials such as timber and hand-worked wrought iron.