I will describe my work with N.Nekrasov on supersymmetric interfaces in gauge theories in the context of the Bethe/gauge correspondence. These interfaces, viewed as operators on the Hilbert space, give linear maps between spaces of SUSY vacua, understood mathematically as generalized cohomology theories of the Higgs branch. A natural class of interfaces are SUSY Janus interfaces for masses, with the corresponding cohomological maps being either the stable envelopes or the chamber R-matrices (both due to Maulik-Okounkov and Aganagic-Okounkov). Thus, such interfaces (and their collisions) can be used to define actions of the spectrum generating algebras (such as Yangians) on the “gauge” side of the Bethe/gauge correspondence, i.e., in QFT. Further applications and possible generalizations will be mentioned as well. ------------------- Part of the London Integrability Journal Club. Please register at integrability-london.weebly.com if you are a new participant. The link will be emailed on Tuesday.