Design Driver Onboarding - System Design | WinJob

Problem Statement: Trust-Gated Driver Supply

Phase understanding — Onboarding design note #1. This section anchors trust-gated supply pipeline for Uber, Lyft, and DoorDash-class marketplaces. Uber/Lyft/DoorDash must vet millions of independent contractors before they touch passengers or food. Onboarding is a compliance workflow—not a signup form.

Signal	What to measure
Case pipeline	time_to_first_trip_hours
Quality	false_positive_rejection_rate vs unsafe_approval_rate
Ops load	manual_review_queue_depth and reviewer_throughput
Compliance	audit_retention and jurisdiction-specific rule packs

Interviewers probe whether you treat onboarding as a workflow + evidence problem, not CRUD on a user row. Unique key for this section: sec-001-trust-gated supply pipeline-1.

Mechanism

Applicant submits immutable application version.
Workflow fans out vendor checks with correlation IDs.
Evidence vault stores artifacts; OCR feeds structured fields.
Merge gates require all blocking checks PASS.
Ops can override with reason code; activation event is idempotent.

Edge cases

Applicant uploads blurry license → manual queue with resubmit link.
Vendor webhook arrives before mobile ACK → reconcile by vendor_ref.
Duplicate device fingerprint → force manual even if MVR clear.
Market rule change mid-flight → version policies; never retroactively fail without notice.

Failure drills

Vendor outage: pause auto-approve; extend SLA timers.
Double activation event: dedupe on case_id in driver profile service.
PII leak attempt: vault denies; break-glass logged.

Checkpoints

(sec-001) State machine owned by workflow worker only.
(sec-001) Idempotency-Key on create application API.
(sec-001) Outbox for driver.activated downstream.
(sec-001) CAP: CP for case state; async analytics OK AP.

Code anchors

javaOne Dark Pro

1 public record OnboardingCaseId(UUID value, String marketCode) {}

pythonOne Dark Pro

1 def is_terminal(state: str) -> bool:
2     return state in {"APPROVED", "REJECTED", "WITHDRAWN"}

typescriptOne Dark Pro

1 export type OnboardingState = 'DRAFT' | 'SUBMITTED' | 'IN_REVIEW' | 'APPROVED' | 'REJECTED';

Why interviewers care

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

Interview checkpoint

Name one failure story for Problem Statement: Trust-Gated Driver Supply that proves you understand real outages, not happy-path diagrams.

Key Highlights

•Anchor trust-gated supply pipeline
•Case workflow owns state transitions
•Evidence vault with vendor correlation
•Activation event is idempotent downstream

1	def is_terminal(state: str) -> bool:
2	return state in {"APPROVED", "REJECTED", "WITHDRAWN"}