Did the Salesforce senior SWE (roughly L5 equivalent) system design round in March. Writing this up because there's almost nothing current out there on what their system design bar looks like.
First thing: Salesforce doesn't call levels L5 like Google does. Their internal levels for senior SWE are around MTS II (Member of Technical Staff II) depending on the org. Worth knowing if you ask the recruiter about leveling.
The design round itself was 60 minutes. The prompt I got was something like: "Design a notification delivery system that supports email, SMS, and push, and can handle 50 million users." Classic distributed systems problem.
What they cared about: Clarifying requirements before diving in. The interviewer pushed back hard when I started designing before scoping. He wanted me to ask about SLAs, delivery guarantees (at-least-once vs exactly-once), and scale. High-level architecture first, then zoom in. I drew out components on the shared whiteboard tool and he kept asking "what's the bottleneck here." Tradeoffs. Not just what you pick but why. Fan-out vs pull model for notification delivery, queue vs direct delivery, etc. They asked about multi-tenancy specifically. Salesforce is a CRM serving enterprise clients, so questions like "how do you isolate one customer's data/traffic from another" came up. I don't think every company asks this but it's core to Salesforce's product reality.
They did NOT ask me to write code during the design round. It was purely whiteboard/architecture.
Level expectation felt higher than "draw a few boxes and name some services." You need to own the conversation, proactively address failure modes, and reason about scale without them having to pull it from you.
Overall I'd say it was a fair interview. Not gotcha-heavy. If you've done system design prep at all you know the drill. Just make sure you're ready to talk multi-tenancy and enterprise data isolation.