Building the data-fabric behind hundreds of billions of files at Dropbox scale

A senior (IC4) infrastructure engineering role on Dropbox's remote-Poland EPD team, building backend systems that manage metadata for hundreds of billions of files and hundreds of petabytes of data. The bar is 9+ years of experience building large multi-threaded, geographically distributed backend systems in Python, Go, C/C++, or Java, plus comfort setting medium-to-long-term technical strategy under ambiguity.

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What this interview tests

Large-scale distributed systems design (metadata at massive file-count scale)
Multi-threaded, geographically dispersed backend architecture
OS internals, filesystems, databases, networking, compilers depth
Setting medium-to-long-term technical strategy and roadmaps
Operating in ambiguity and open-ended problem solving
Cross-functional collaboration and on-call ownership at scale

Common question themes

Design a metadata storage system that must scale to hundreds of billions of files

Tell me about the most geographically distributed or multi-threaded backend system you've built

Describe a time you had to set technical direction under real ambiguity, with no clear right answer

How do you think about consistency, availability, and partial failure in a system serving millions of concurrent connections

Tell me about a long-term project you owned end to end and how you drove it to completion

How would you approach improving interoperability across many disparate services/ecosystems

How candidates describe it

Real Senior Infrastructure Software Engineer interview stories — retold from candidates' public write-ups, with sources.

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