The Senior iOS overlay — turn the DSA grind into a senior hire.
The SWE prep guide gets you over the coding bar. But a senior iOS loop tests something the algorithm grind never touches: can you own a codebase, design for offline, profile a launch, kill a memory leak, set up CI, and influence architecture? This overlay pairs every one of the 24 SWE weeks with a real senior iOS task, so that by interview day you've not just solved LeetCode — you've shipped a portfolio of senior work and have the case studies to prove it.
Three loops, three flavours
USA leans DSA + system design; Singapore weighs product ownership, security & reliability; Australia prizes practical build, architecture & communication. Tune your last 20% to where you're applying.
A task every week
Refactor a module, write the tests, profile the launch, migrate UIKit→SwiftUI, design offline sync, add CI, hunt a memory leak — one concrete senior deliverable per week, building on the last.
Stories + a take-home + a gate
Convert the work into five senior case-study templates, rehearse a full take-home build, and clear a readiness gate of mocks before you say yes to the loop.
Three senior-iOS loops, decoded by region
A senior iOS loop has the same spine everywhere — coding, iOS architecture, mobile system design, behavioral, often a practical build — but the weighting shifts sharply by market. The bars below are the author's calibration of emphasis, not official numbers; use them to decide where to spend your final polish. Green tag = the dimension this region over-indexes on.
The 24-week Senior iOS overlay
One senior iOS task laid over each SWE week, grouped into the same six phases. Each task names a skill and a concrete deliverable you'll have shipped by Friday — they chain together on a single app you own. Tick weeks off as you go; progress saves in this browser (separately from your SWE progress). Pick a phase tab to expand it.
The take-home / live build, mastered
Senior iOS loops increasingly replace a whiteboard with a practical build: "here's an API — build a small feature." It looks easy and quietly separates seniors from mids. The signal isn't that the happy path works — it's that you handled the states nobody demos, made it testable, and can defend every call. These eight things are what graders actually tick. The full offline walkthrough — with reference SwiftUI, tests, and a self-scoring checklist — lives in this kit.
Five senior case-study templates
Senior behavioral rounds aren't "tell me about a conflict" — they probe judgement under your own authority. These are the five stories every senior iOS loop fishes for. Each template gives you the STAR scaffold, the senior signals it must land, the prompts that draw it out, and what a strong answer sounds like. Fill each with your real work from the overlay above — that's the point of doing the tasks. Tap a card to open it.
The Senior iOS readiness gate
Don't accept a loop on vibes. Clear this gate first — it's the senior-iOS equivalent of a pre-flight checklist. Each item is a rep you complete under realistic conditions, not a topic you read. Tick them as you pass them; the gate verdict below flips to ready only when all of them are green. Progress saves in this browser.
The senior-iOS interview-day playbook
The SWE guide's coding / system-design / behavioral skeletons still apply — this is the senior-iOS layer on top of them.
The iOS architecture round — narrate this frame
Frame the feature
Restate what the screen/feature must do, the states it can be in (loading/error/empty/loaded), and the non-functionals: offline, accessibility, performance budget.
Draw the layers
View ↔ presentation (VM/store) ↔ domain ↔ data. Name where state lives, the direction dependencies point, and the seams you'd inject for tests.
Make state explicit
Model a single source of truth, unidirectional updates, and how async work lands back on the main actor. Call out value vs reference semantics.
Reason about threads
async/await + actors; what's isolated to the main actor; where a data race or retain cycle could hide and how you'd prove it doesn't.
Show the seams
Protocol-backed dependencies, a fake at the boundary, the few high-value tests you'd write first. "Here's the unit I'd test and how I'd inject the network."
Defend one decision
Pick the interesting call (SwiftData vs Core Data, MVVM vs TCA, when to modularise) and name what you traded and why. That judgement is the senior signal.