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Mavenclinic·Backend Engineer·Onsite - System Design / Architecture·Senior

SeniorPrefer not to say
May 2026

Summary

System design round at Mavenclinic for a backend engineer role, focused entirely on building a therapist-patient matching marketplace. Dense problem with a lot of moving parts, from search and ranking to booking consistency and HIPAA-adjacent compliance concerns.

Questions Asked (7)

Q1

Design the backend for a marketplace that matches patients with therapists, covering search, booking, availability, and ranking.

System DesignData ModelingTechnical Trade-offs
Author's notes

Big open-ended prompt.

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AI HintsAI Generated

Suggested Approach

Start by clarifying functional and non-functional requirements, then design the core data model and APIs for search, booking, and availability. Discuss ranking algorithms and trade-offs, and wrap up with scalability and reliability considerations.

Pro tip: Emphasize how you would handle real-world constraints like double-booking prevention, time zone complexities, and ranking fairness, showing you understand the domain beyond just technical components.

1. Clarify Requirements and Scope

Ask questions to understand user needs, scale, and constraints (e.g., search filters, booking rules, ranking factors). Define functional and non-functional requirements.

2. Design Data Model and APIs

Outline entities like Patient, Therapist, Availability, Booking, and Review. Define RESTful or GraphQL APIs for search, booking, and availability management.

3. Architect Core Services

Propose services for search (with indexing), booking (with concurrency control), availability (with calendar integration), and ranking (with scoring). Discuss data stores (SQL, NoSQL, search engine).

4. Address Ranking and Matching

Explain how to rank therapists based on relevance, availability, ratings, and other factors. Discuss algorithms (e.g., weighted scoring, machine learning) and trade-offs.

5. Discuss Scalability and Reliability

Cover scaling strategies (sharding, caching, read replicas), consistency models, and failure handling (idempotency, retries, circuit breakers).

Key Points to Mention

  • Double-booking prevention using optimistic locking or distributed transactions
  • Time zone handling and recurring availability slots
  • Search indexing with Elasticsearch or similar for full-text and geo search
  • Ranking factors: relevance, availability, ratings, and personalization
  • Caching strategies for frequently accessed data like therapist profiles
  • Event-driven architecture for notifications and updates

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q2

How would you handle search and ranking of therapists for a given patient, considering specialty, insurance, location, language, modality, price, and availability?

System DesignTechnical Trade-offs
Author's notes

This is where I felt most comfortable.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and constraints, then propose a multi-stage retrieval and ranking pipeline that balances relevance and business rules. Discuss trade-offs between hard filters and soft scoring, and how to handle availability and price dynamically.

Pro tip: Emphasize that availability and price are often the most critical factors for patients, so design the system to prioritize them without sacrificing other criteria. Also, mention the importance of A/B testing and monitoring to continuously improve ranking.

1. Clarify Requirements and Constraints

Ask questions to understand scale, latency requirements, data freshness, and business priorities (e.g., which factors matter most).

2. Design Data Model and Indexing

Outline how to store therapist attributes (specialty, insurance, location, language, modality, price, availability) in a searchable index, considering geospatial and time-based queries.

3. Implement Retrieval and Filtering

Use hard filters for non-negotiable criteria (e.g., insurance, language) and soft filters for others, leveraging a search engine like Elasticsearch for efficient retrieval.

4. Develop Ranking and Scoring

Define a scoring function that combines relevance (e.g., specialty match) with business rules (e.g., price, availability) and personalization, using weighted factors or machine learning.

5. Handle Dynamic Factors and Scalability

Address real-time availability and price updates, caching strategies, and horizontal scaling to meet latency and throughput requirements.

Key Points to Mention

  • Use of Elasticsearch or similar for geospatial and full-text search
  • Hard filters vs. soft scoring for different criteria
  • Ranking function design: weighted sum, learning-to-rank, or business rules
  • Handling real-time availability and price updates
  • Caching and precomputation for performance
  • A/B testing and metrics for continuous improvement

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q3

How do you prevent double booking and deal with stale availability data?

System DesignTechnical Trade-offs
Author's notes

I blanked for a second here.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the requirements and constraints, such as the scale, consistency needs, and user experience. Then propose a layered strategy: prevent double booking at the database level with transactions and constraints, and handle stale availability data through optimistic UI updates, versioning, and revalidation. Discuss trade-offs between strong and eventual consistency, and how to handle conflicts gracefully.

Pro tip: Emphasize idempotency and conflict resolution: use idempotent booking requests to avoid duplicates, and design a clear conflict resolution flow (e.g., waitlist or alternative slots) to maintain a good user experience even when double booking is prevented.

1. Clarify requirements and constraints

Ask about scale, consistency requirements, and user experience expectations. Determine if the system is read-heavy or write-heavy, and whether eventual consistency is acceptable.

2. Prevent double booking at the data layer

Use database transactions with isolation levels (e.g., serializable) or unique constraints on time slots. Consider optimistic concurrency control with version numbers or timestamps.

3. Handle stale availability data

Implement optimistic UI updates with revalidation on the server. Use versioning or ETags to detect stale data, and provide clear feedback if a slot is no longer available.

4. Design for idempotency and conflict resolution

Make booking requests idempotent using idempotency keys. Define a conflict resolution strategy, such as offering alternative slots or a waitlist.

5. Discuss trade-offs and monitoring

Compare strong vs. eventual consistency, and explain how you balance performance and correctness. Mention monitoring for double booking attempts and stale data rates.

Key Points to Mention

  • Database transactions and isolation levels (e.g., serializable, repeatable read)
  • Unique constraints or exclusion constraints on time ranges
  • Optimistic concurrency control (versioning, timestamps, ETags)
  • Idempotency keys for booking requests
  • Eventual consistency and revalidation strategies
  • Conflict resolution and user experience (waitlist, alternative slots)

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q4

Walk through the API design for booking, cancellation, and waitlists.

API & IntegrationsSystem Design
Author's notes

Covered the obvious endpoints but the waitlist part caught me a bit flat.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the core requirements and constraints (e.g., booking rules, cancellation policies, waitlist behavior) before diving into API design. Then walk through the resource model, endpoints, and key flows for booking, cancellation, and waitlist management, emphasizing idempotency, concurrency, and error handling. Finally, discuss trade-offs and how you would evolve the design for scale and reliability.

Pro tip: Proactively address race conditions and idempotency—e.g., using idempotency keys for booking and cancellation, and optimistic locking or distributed locks for slot allocation—to show you understand real-world backend challenges.

1. Clarify Requirements and Constraints

Ask questions to understand booking rules (e.g., advance notice, duration), cancellation policies (e.g., fees, cutoff times), and waitlist behavior (e.g., auto-promotion, expiration). Identify non-functional requirements like consistency, latency, and scale.

2. Define Resources and Data Model

Outline core resources: Appointment, Slot, Booking, WaitlistEntry, and Cancellation. Specify their attributes, relationships, and state transitions (e.g., booked, cancelled, waitlisted).

3. Design API Endpoints and Flows

Propose RESTful endpoints for booking (POST /bookings), cancellation (DELETE /bookings/{id} or POST /bookings/{id}/cancel), and waitlist (POST /waitlist, GET /waitlist). Describe request/response payloads and status codes for success and errors.

4. Address Concurrency, Idempotency, and Error Handling

Explain how to prevent double-booking using transactions or locks, ensure idempotent operations with idempotency keys, and handle common errors (e.g., slot unavailable, already cancelled, waitlist full) with appropriate HTTP codes and messages.

5. Discuss Trade-offs and Evolution

Highlight trade-offs (e.g., strong vs. eventual consistency, synchronous vs. asynchronous waitlist promotion) and how the design could evolve for scale, reliability, and new features like recurring bookings.

Key Points to Mention

  • Idempotency keys for booking and cancellation to prevent duplicate operations.
  • Concurrency control (e.g., optimistic locking, database transactions, or distributed locks) to avoid double-booking.
  • Waitlist management: automatic promotion when a slot opens, notification mechanisms, and expiration policies.
  • Clear error handling and HTTP status codes (e.g., 409 Conflict for slot taken, 410 Gone for cancelled booking).
  • API versioning and pagination for waitlist and booking history endpoints.
  • Security and authorization: ensuring only authorized users can book, cancel, or view waitlists.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q5

What privacy and compliance considerations apply here, given that this is sensitive health data?

Technical Trade-offsSystem Design
Author's notes

HIPAA came up immediately.

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AI HintsAI Generated

Suggested Approach

Start by acknowledging that health data is among the most sensitive categories, governed by regulations like HIPAA and GDPR. Then, walk through the data lifecycle—collection, storage, processing, and sharing—highlighting specific technical controls and compliance requirements at each stage. Emphasize a defense-in-depth approach that balances privacy, security, and usability.

Pro tip: Demonstrate awareness that privacy is not just about encryption; it's about minimizing data collection, enforcing strict access controls, and ensuring auditability. Mention that you would involve legal and compliance teams early in the design process to avoid costly rework.

1. Identify applicable regulations

Determine which laws and standards apply based on the data types and jurisdictions, such as HIPAA for protected health information (PHI) in the US, GDPR for EU residents, and possibly local laws. This sets the baseline for compliance.

2. Map data flows and classify data

Trace how sensitive health data enters, moves through, and exits your system. Classify data by sensitivity to apply appropriate controls, ensuring you know where PHI resides and how it's protected.

3. Implement technical safeguards

Apply encryption at rest and in transit, strict access controls (e.g., role-based access, least privilege), audit logging, and data minimization techniques like de-identification or pseudonymization where possible.

4. Establish policies and procedures

Define and enforce policies for data retention, deletion, breach notification, and user consent. Ensure these are documented and regularly reviewed to adapt to changing regulations.

5. Monitor, audit, and train

Continuously monitor access and usage, conduct regular audits, and provide ongoing privacy training to engineers and staff. This ensures compliance is maintained and incidents are detected early.

Key Points to Mention

  • HIPAA Privacy and Security Rules, including the requirement for Business Associate Agreements (BAAs) with third-party services.
  • GDPR principles such as data minimization, purpose limitation, and the right to erasure.
  • Encryption standards (e.g., AES-256 for data at rest, TLS 1.2+ for data in transit) and key management.
  • Access control mechanisms like RBAC, MFA, and the principle of least privilege.
  • Audit logging and monitoring for unauthorized access or anomalies.
  • Data anonymization or pseudonymization techniques to reduce risk when using data for analytics or testing.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q6

How would you enforce region and licensure constraints so therapists only appear for patients they're legally allowed to treat?

System DesignData Modeling
Author's notes

Didn't expect this to be its own thread of the conversation.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the core requirement: filtering therapists based on patient location and therapist licensure. Then propose a data model that stores licensure and region data, and describe how to enforce constraints at query time and possibly at write time. Emphasize the need for accuracy and compliance, and discuss trade-offs between real-time checks and precomputed eligibility.

Pro tip: Mention that licensure rules can change and that you'd design for auditability and easy updates, perhaps using a rules engine or configuration service. Also, consider edge cases like patients in multiple regions or therapists with multiple licenses.

1. Clarify Requirements and Constraints

Ask questions to understand the exact rules: Are regions defined by state, country, or something else? How often do licensure rules change? What is the expected scale?

2. Design Data Model

Propose tables/collections for therapists, their licenses (with region and expiration), patients (with location), and a mapping of region to licensure requirements. Consider normalization vs. denormalization for performance.

3. Enforce Constraints at Query Time

Describe how to filter therapists when a patient searches: join therapist licenses with patient region, check validity and expiration. Discuss indexing and caching for performance.

4. Handle Updates and Edge Cases

Explain how to handle changes in licensure or patient location: invalidate caches, update precomputed lists, and ensure eventual consistency. Address edge cases like multi-state licenses or patients in transit.

5. Ensure Compliance and Auditability

Mention logging, auditing, and possibly a separate service to manage licensure rules. Discuss how to test and monitor the system to prevent violations.

Key Points to Mention

  • Data model: therapists, licenses (region, expiration), patients (location), region-license mapping
  • Query-time filtering with proper indexing and caching
  • Handling dynamic licensure rules and updates
  • Edge cases: multi-region patients, therapists with multiple licenses, expiration
  • Auditability and compliance logging
  • Trade-offs: real-time vs. precomputed eligibility, consistency vs. performance

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q7

How would you scale this system as the platform grows in users and therapists?

System DesignTechnical Trade-offs
Author's notes

Standard scaling question.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the current architecture and growth projections, then identify bottlenecks in the user and therapist flows. Propose a phased scaling strategy that addresses database, application, and infrastructure layers, emphasizing trade-offs between consistency, availability, and cost.

Pro tip: Focus on the therapist-side scaling challenges (e.g., scheduling, real-time availability) as they often have stricter consistency requirements than user-side features. Mention specific technologies you've used to solve similar problems, but always tie them back to business impact.

1. Clarify Requirements and Current State

Ask about expected growth rates, read/write patterns, and any SLAs. Briefly summarize the existing architecture to ensure alignment.

2. Identify Bottlenecks and Scaling Dimensions

Analyze components like database, API servers, caching, and third-party integrations. Determine which will hit limits first as users and therapists grow.

3. Propose Scaling Strategies per Layer

For each bottleneck, suggest horizontal scaling, sharding, read replicas, caching, async processing, or microservices. Explain how they address the specific growth.

4. Discuss Trade-offs and Priorities

Highlight trade-offs such as consistency vs. availability, latency vs. cost, and complexity vs. time-to-market. Prioritize based on business needs.

5. Outline an Incremental Roadmap

Propose a phased approach: quick wins first, then more complex changes. Include monitoring and metrics to validate each phase.

Key Points to Mention

  • Database scaling: read replicas, sharding, partitioning, and choosing the right database (SQL vs. NoSQL) for different data types.
  • Caching strategies: Redis or Memcached for session data, frequent queries, and therapist availability.
  • Asynchronous processing: message queues (e.g., RabbitMQ, Kafka) for background tasks like notifications, video processing, and scheduling.
  • Horizontal scaling: stateless services, load balancing, auto-scaling groups, and container orchestration (e.g., Kubernetes).
  • Therapist-specific scaling: handling real-time scheduling, double-booking prevention, and consistency in appointment booking.
  • Monitoring and observability: metrics, logging, tracing, and alerting to proactively detect scaling issues.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.