Senior Site Reliability Engineer

Mozilla • London, England, United Kingdom • Posted June 10, 2026

Location London, England
Job Type Full-time
Category Computer Occupations
Posted June 10, 2026

Senior Site Reliability Engineer

at MZLA/Thunderbird Locations: Remote Canada, Remote UK, Remote US

Why Thunderbird?


Thunderbird is one of the world’s most trusted open-source email applications, empowering more than 20 million people globally. At MZLA, the team behind Thunderbird, we build privacy-respecting communication tools that help people manage their digital lives while staying in control of their data.


We are open source by design. Our products are developed transparently and in collaboration with a global community of contributors, and that same spirit shapes how we work: collaboratively, inclusively, and with a shared commitment to putting users first.


Our small but growing distributed team includes 65+ people across seven countries. As Thunderbird evolves beyond a single desktop application, we are expanding across desktop, mobile, and paid services to build independent, privacy-respecting alternatives to big tech...

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