Plaid interview questions

Showing 1–16 of 16 results

• Calculate Ordered Job Makespan Across Parallel WorkersMedium

  Calculate the total makespan required to process a queue of ordered jobs across a fixed pool of identical parallel workers.

  PlaidSoftware EngineerCoding & AlgorithmsTechnical Screen
• Compute discounted prices in a queueMedium

  This question evaluates proficiency in array processing, algorithm design, use of auxiliary data structures such as monotonic stacks, and formal complexity and correctness reasoning.

  PlaidSoftware EngineerCoding & AlgorithmsTechnical Screen
• Count Completed Jobs in a Serial Multi-Worker PipelineMedium

  Calculate the total number of jobs completed by a given deadline across a multi-stage pipelined system with worker pools. The solution requires simulating stage-by-stage batch execution, tracking wave durations, and enforcing barrier synchronization between stages.

  PlaidSoftware EngineerCoding & AlgorithmsTechnical Screen
• Count Completed Jobs in a Serial Single-Worker PipelineMedium

  Determine the total number of jobs completed by a single worker executing a sequence of stage-gated tasks before a time limit expires. Tests linear simulation, division/modulo arithmetic, handling of zero-duration and zero-count edge cases, and 64-bit integer safety.

  PlaidSoftware EngineerCoding & AlgorithmsTechnical Screen
• Design RAG Evaluation and DebuggingMedium

  Design a comprehensive evaluation, monitoring, and debugging framework for a production Retrieval-Augmented Generation (RAG) system operating in a high-stakes financial data domain. The candidate must address multi-stage metrics, CI/CD regression testing, and root-cause localization for retrieval vs. generation failures.

  PlaidMachine Learning EngineerML System DesignOnsite
• Design a ChatGPT-like conversational assistantEasy

  This question evaluates a candidate's ability to design large-scale conversational AI systems, covering competencies in distributed system architecture, real-time streaming, stateful multi-turn session management, safety controls, and integration with external tools.

  PlaidSoftware EngineerSystem DesignTechnical Screen
• Design a Fraud Detection SystemMedium

  This question evaluates competency in ML system design for fraud detection within fintech data-connectivity platforms, testing real-time scoring, feature engineering (including relational/graph signals), label strategy, model training and serving, and operational concerns such as latency, privacy, monitoring, and robustness.

  PlaidMachine Learning EngineerML System DesignTechnical Screen
• Design a coupon redemption systemMedium

  This question evaluates proficiency in data structures and algorithms for building an in-memory service, including efficient lookup/update strategies, expiration handling, limit enforcement, idempotency, concurrency considerations, and time/space complexity reasoning.

  PlaidSoftware EngineerCoding & AlgorithmsTechnical Screen
• Design a geo-distributed rate limiterEasy

  This question evaluates a candidate's competency in designing geo-distributed, globally consistent rate limiting systems that enforce per-API-key and additional constraints while balancing low-latency request paths and regional failure tolerance.

  PlaidSoftware EngineerSystem DesignTechnical Screen
• Design an Embeddable Pay by Bank WidgetMedium

  Design a secure, embeddable Pay by Bank frontend widget and supporting backend infrastructure that enables direct bank checkout via an isolated iframe and asynchronous payment processing.

  PlaidSoftware EngineerSystem DesignOnsite
• Explain What You Seek and an Unexpected Project OutcomeMedium

  Tests candidate self-awareness, career motivation, and adaptability when technical initiatives diverge from expectations due to real-world constraints.

  PlaidSoftware EngineerBehavioral & LeadershipOnsite
• Explain project scope, timeline, and delegationMedium

  This question evaluates project management, technical ownership, estimation, risk management, delegation, and cross-team communication competencies within the Behavioral & Leadership domain for software engineers.

  PlaidSoftware EngineerBehavioral & LeadershipTechnical Screen
• Reason About Rate Limiting Under Memory and Throughput PressureMedium

  Tests the candidate's ability to design a high-throughput, memory-bounded rate limiter using bucketed counters instead of unbounded timestamp queues, balancing concurrency, memory overhead, and precision.

  PlaidSoftware EngineerSoftware Engineering FundamentalsOnsite
• Resolve routing-number to bank mappingEasy

  This question evaluates a candidate's skills in data normalization, deduplication, aggregation, and conflict resolution across multiple JSON data sources, with emphasis on canonicalization of aliases and handling inconsistent mappings.

  PlaidSoftware EngineerCoding & AlgorithmsTechnical Screen
• Validate Evaluation Chains and Resolve Boolean OutcomesMedium

  Implement a graph traversal to resolve Boolean evaluation chains with negation, detecting cycles, paths leading to cycles, and undefined references in linear time.

  PlaidSoftware EngineerCoding & AlgorithmsTechnical Screen
• Validate and Resolve Chained Decision RulesMedium

  Determine if all rules in a chained decision rule set resolve to a terminal 'pass' outcome without cycles or missing references.

  PlaidSoftware EngineerCoding & AlgorithmsTechnical Screen