Design ledger and bikemap integration

Q: Design ledger and bikemap integration

This question evaluates competency in designing strongly consistent financial ledgers and integrating an external routing service, testing data modeling, distributed transactions, linearizability and idempotency, scalability, security, API design, and observability in the System Design domain.

Q: How do I approach System Design interview questions?

System Design questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master system design interviews.

Q: What difficulty level is this interview question?

This is a hard difficulty System Design question, commonly asked during Onsite rounds at Stripe.

Q: What role is this question designed for?

This question is commonly asked for Software Engineer candidates at Stripe during technical interviews.

Question

System Design: Strongly Consistent Ledger and External Service Integration

Context and Goal

You are asked to design two components in a production-grade environment:

A financial ledger with strong consistency and high scalability.
An integration of an external "Bikemap" routing library/service into a larger application.

Assume:

Money movement requires correctness over availability. Writes must be strongly consistent. Reads can be tuned for performance while preserving correctness.
Bikemap is a third-party routing API used to fetch bicycle routes/metadata; think of it as a network API with SLAs, rate limits, and versioned contracts.

Part A — Ledger System Requirements

Design a ledger that provides:

Consistency and correctness
- Double-entry accounting (every transaction balances to zero).
- Immutability and auditability (no destructive updates; reversible corrections).
- Idempotent writes; exactly-once effects externally.
- Strong write consistency (linearizable writes, serializable transactions).
Scalability and performance
- High write throughput; horizontal scaling.
- Efficient balance reads (point-in-time and as-of time).
Reliability and security
- Multi-AZ durability, backups, disaster recovery.
- Encryption at rest/in transit; access controls.
Interfaces and operations
- Well-defined APIs (create account, transfer, hold/release, reverse, query balance, list transactions).
- Observability, schema evolution, and operational playbooks.

Describe: data model, write/read paths, sharding strategy, multi-account transaction handling, audit guarantees, idempotency, and failure handling.

Part B — Integrate an External Bikemap Service

Explain how you would integrate an external Bikemap library/service into a larger application, covering:

API design
- Internal domain API that remains stable even if the provider changes.
- Versioning, contracts, and auth/secrets management.
Data flow
- Request flow, caching, rate limiting, retries, timeouts, and circuit breakers.
- Sync vs async flows and background jobs.
Error handling and resilience
- Error taxonomy, fallback strategies, and observability.
Deployment considerations
- Environment promotion (dev/staging/prod), canaries, feature flags, infrastructure, and testing strategies.

Design ledger and bikemap integration

Quick Overview

System Design: Strongly Consistent Ledger and External Service Integration

Context and Goal

Part A — Ledger System Requirements

Part B — Integrate an External Bikemap Service

Solution

Comments (0)

Design ledger and bikemap integration

Quick Overview

System Design: Strongly Consistent Ledger and External Service Integration

Context and Goal

Part A — Ledger System Requirements

Part B — Integrate an External Bikemap Service

Solution

Comments (0)