Walmart Labs Product Designer Case: Omni‑Channel Grocery Pickup & Substitutions

This case mirrors real Walmart Labs (Walmart Global Tech) product design interviews, where candidates tackle complex, operations-heavy retail problems at massive scale. You’ll design an improved end‑to‑end curbside pickup experience for Walmart Grocery on mobile (iOS/Android), with a deep dive on time‑slot selection, check‑in, parking‑lot handoff, and item substitutions. The interview emphasizes pragmatic product thinking, service design across store + app + last‑mile, measurable outcomes, and accessibility—hallmarks of Walmart’s culture (customer‑obsessed, data‑informed, operationally grounded, and frugal). What you’ll do: 1) Clarify and align (8–10 min): Identify primary users (customer, store associate, Spark Driver), success metrics (conversion, slot fill rate, wait time from arrival to handoff, substitution acceptance rate, CSAT, labor minutes/order), constraints (low bandwidth in lots, GPS drift, ADA compliance, multilingual needs, privacy), and business guardrails (EDLP/EDLC mindset, cost to serve, fraud prevention). 2) Map the service (10–12 min): Sketch the key journey stages—Browse → Cart → Slot selection → Substitution preferences → Arrival/check‑in (geo‑fence vs manual) → Handoff → Post‑order (ratings/returns). Call out store‑ops touchpoints (associate picking app, staging areas, parking signage) and failure/edge cases (no‑show, out‑of‑stock at pick time, weather, multi‑order in one vehicle, alcohol/age‑verify). 3) Propose UX flows (15–18 min): Present wireframe‑level flows for: a) Slot selection that balances demand shaping and transparency (cut‑off times, capacity); b) Substitution controls (global vs per‑item rules, brand/price thresholds, ‘don’t substitute’) with clear price deltas; c) Arrival and check‑in that works with spotty GPS and supports license plate/spot number; d) Real‑time status and associate communications (asynchronous updates, safe messaging, language support). Explain information hierarchy, error states, and accessibility (WCAG 2.1 AA, high contrast, large tap targets, VO labels). 4) Instrumentation & experimentation (8–10 min): Define event logging, guardrail metrics (NPS/CSAT, OTD, cancellations), and an A/B plan (e.g., demand‑shaping slot UI vs control). Discuss trade‑offs between conversion and cost to serve, and how to mitigate dark patterns. 5) Cross‑functional plan (6–8 min): Outline how you’d partner with Store Operations, Last‑Mile, Data Science, Engineering, and Legal/Compliance. Cover rollout (pilot → staged ramp by market capacity), localization, and change management for associates. What interviewers evaluate: 1) Problem framing rooted in customer + ops reality; 2) Systems thinking across digital and physical; 3) Craft and clarity in flows/states; 4) Metrics‑driven decision making; 5) Awareness of scale, accessibility, and privacy; 6) Communication and prioritization under time constraints. Candidate materials allowed: marker/whiteboard or virtual canvas; low‑fi sketches are expected (hi‑fi not required). Deliverable by end: a clearly articulated North Star, a prioritized MVP scope (e.g., improved substitutions + resilient check‑in), key screens/flows, and a metrics plan tied to business outcomes.