Design Delivery Instructions - System Design | WinJob

Problem Statement: Special Instructions at Marketplace Scale

Design DoorDash/Amazon/Instacart-class delivery instructions: structured drop-off preferences, access codes, and order-scoped overrides propagated to couriers in near real time. This section covers problem statement: special instructions at marketplace scale in the understanding phase.

Operational detail

Instruction read p95 <120ms on driver app; push delivery p95 <3s after post-dispatch edit before pickup complete.

Failure and edge cases

Customer edits instructions after food is picked up—kitchen already printed bag labels with old notes

Interview checkpoints

Interview note (sec-01)

When presenting Problem Statement: Special Instructions at Marketplace Scale, cite instruction_revision_id, order snapshot pinning, and courier push fanout—not generic delivery instructions blobs.

javaOne Dark Pro

1 public record InstructionRevisionId(String value) {
2   public static InstructionRevisionId mint() {
3     return new InstructionRevisionId("ir_" + java.util.UUID.randomUUID());
4   }
5 }

pythonOne Dark Pro

1 def merge_order_snapshot(address: dict, override: dict | None) -> dict:
2     base = {k: address[k] for k in ("drop_off", "access_code", "notes")}
3     if override:
4         base.update({k: v for k, v in override.items() if v is not None})
5     return base

typescriptOne Dark Pro

1 export interface OrderInstructionSnapshot {
2   revisionId: string;
3   dropOff: "DOOR" | "HANDOFF" | "LOCKER";
4   accessCode?: string;
5   notes?: string;
6 }

Why interviewers care

Delivery Instructions interviews reward crisp scope, explicit trade-offs, and failure stories—not generic microservice diagrams.

Interview checkpoint

Name one failure story for Problem Statement: Special Instructions at Marketplace Scale that proves you understand real outages, not happy-path diagrams.

Key Highlights

•Consumers save reusable instructions on an address profile (gate code, leave at door, ring bell)
•Each order pins an instruction_revision_id at checkout so fee disputes reference frozen text
•Couriers see structured chips plus optional free-text within character caps
•Post-dispatch edits fan out to assigned courier via push within seconds

1	public record InstructionRevisionId(String value) {
2	public static InstructionRevisionId mint() {
3	return new InstructionRevisionId("ir_" + java.util.UUID.randomUUID());
4	}
5	}

1	def merge_order_snapshot(address: dict, override: dict \| None) -> dict:
2	base = {k: address[k] for k in ("drop_off", "access_code", "notes")}
3	if override:
4	base.update({k: v for k, v in override.items() if v is not None})
5	return base

1	export interface OrderInstructionSnapshot {
2	revisionId: string;
3	dropOff: "DOOR" \| "HANDOFF" \| "LOCKER";
4	accessCode?: string;
5	notes?: string;
6	}