A senior IC is judged mainly by what they build: hard problems solved, high-quality code, deep expertise. A tech lead is judged by what the team builds. The title is less a promotion above senior IC and more a different shape of work focused on multiplying others.
The key shift
Senior IC Tech Lead
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Depth in the code Breadth across the project
Solves the hard problem Makes sure the right problems get solved
Optimizes own throughput Optimizes the team's throughput
Owns a component Owns the technical outcome
Mostly heads-down Mix of heads-down and coordination
