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Interface Bloat

Fat Interface · Refused Bequests

When an interface accumulates so many methods or options that it becomes unwieldy and nearly impossible to implement correctly. Simplicity is a feature.

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Origin

The concept emerged from object-oriented software design discussions in the 1990s, though the specific term's origin is uncertain. Bjarne Stroustrup, creator of C++, referred to "fat interfaces," while Martin Fowler used the term "Refused Bequests" to describe the same anti-pattern. The phenomenon itself traces to earlier computing: IBM's OS/360, introduced in 1964, exemplified bloat as its design grew to support wide-ranging hardware configurations.

Updated February 22, 2026