torch_xla makes the demo run in an afternoon; making it fast is where migrations die. The lazy-tensor mental model, the recompilation traps, and the honest fork between porting and rewriting in JAX.
Updated Sep 2026 · Grounded in real Forward Deployed Engineer interview loops and written to a senior-engineer editorial bar.
torch_xla makes the demo run in an afternoon; making it fast is where migrations die. The lazy-tensor mental model, the recompilation traps, and the honest fork between porting and rewriting in JAX.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
