▸case-13 When users submit a form, our web server synchronously renders PDF invoices, sends email notifications, and updates third-party CRM APIs before responding to the user request. Response times exceed 8 seconds. The team wants to increase web server worker count from 10 to 100. Evaluate this approach and propose an asynchronous architecture. | pass→pass | 15,692 | 17,778 | +13% | 1 | 1 | 0% | 2,756 | 3,316 | +20% | 0 | 0 | — |
▸case-01 We are migrating our e-commerce platform from a monolith to microservices. The product lead insists on using two-phase commit (2PC) protocol across all microservices to guarantee ACID transactions across services during order checkout. Write an Architecture Decision Record (ADR) analyzing this proposal and proposing an alternative event-driven approach. | pass→pass | 22,195 | 29,233 | +32% | 1 | 1 | 0% | 3,561 | 4,838 | +36% | 0 | 0 | — |
▸case-02 We need a diagram representing our new banking platform architecture. A junior developer created a single flowchart showing every function call and class in the backend code. Prepare a high-level container-level architectural representation using Mermaid diagram syntax for our C4 model documentation. | pass→pass | 13,126 | 15,235 | +16% | 1 | 1 | 0% | 2,711 | 3,074 | +13% | 0 | 0 | — |
▸case-03 Our news media portal experiences 100,000 read requests per second on breaking news articles, but update writes happen only a few times per hour. The database CPU hits 100%. The team lead suggests turning off database indexing to speed up queries. Evaluate this trade-off and propose an architectural caching strategy. | pass→pass | 14,325 | 17,160 | +20% | 1 | 1 | 0% | 2,508 | 3,383 | +35% | 0 | 0 | — |
▸case-04 When an external payment gateway API experiences intermittent latency or outages, our main checkout service thread pool gets exhausted waiting for timeouts, causing cascading failures across our entire platform. The backend team wants to double the HTTP client timeout duration to 60 seconds. Evaluate this suggestion and propose an architectural resilience pattern. | pass→pass | 16,168 | 20,657 | +28% | 1 | 1 | 0% | 2,689 | 3,404 | +27% | 0 | 0 | — |
▸case-05 Our order service updates the relational database and then sends an order-created event to Apache Kafka in the same controller method. During network blips to Kafka, the DB transaction commits but the event is lost, causing data inconsistency between services. A developer suggests wrapping the Kafka send call in a try-catch block and logging the error. Evaluate this fix and propose a reliable architectural pattern. | pass→pass | 14,945 | 13,980 | -6% | 1 | 1 | 0% | 2,656 | 2,703 | +2% | 0 | 0 | — |
▸case-06 Our multi-tenant SaaS application stores all tenant data in a single MySQL table that has grown to 500 million rows. Single-node vertical scaling has reached physical limits, and queries on large tenants cause slow queries across all tenants. The lead engineer wants to disable foreign keys and run night cron jobs to clean old data. Evaluate this proposal and detail an architectural data partitioning strategy. | fail→pass | 22,842 | 26,400 | +16% | 1 | 1 | 0% | 3,456 | 4,717 | +36% | 0 | 0 | — |
▸case-07 Our operational database handles intensive transactional writes while simultaneously executing complex OLAP aggregation queries for real-time dashboards, causing lock contention and degraded write throughput. The team suggests adding aggressive SQL read locks on write operations. Evaluate this trade-off and propose an architectural pattern to segregate reads and writes. | pass→pass | 19,806 | 14,237 | -28% | 1 | 1 | 0% | 2,707 | 2,599 | -4% | 0 | 0 | — |
▸case-08 Public third-party developers are overwhelming our backend services with unthrottled API requests, causing service denial for enterprise users. The infrastructure team proposes placing individual rate-limiting logic inside every microservice's business logic layer. Evaluate this design and propose a centralized architectural solution. | pass→pass | 17,505 | 22,149 | +27% | 1 | 1 | 0% | 2,989 | 3,480 | +16% | 0 | 0 | — |
▸case-09 Our global user base in Asia and Europe experiences high latency (500ms+) accessing static assets and dynamic personalized pages hosted in an AWS us-east-1 region. A developer suggests scaling the EC2 instance size in us-east-1 to a larger instance class. Evaluate this recommendation and outline a multi-region deployment or edge delivery architecture. | pass→pass | 19,132 | 18,529 | -3% | 1 | 1 | 0% | 3,386 | 3,702 | +9% | 0 | 0 | — |
▸case-10 Our legacy monolith is impossible to deploy safely, but management wants to perform a complete 'big bang' rewrite from scratch in 3 months while pausing all feature updates. Draft an ADR evaluating this strategy and proposing an incremental alternative. | pass→pass | 17,537 | 17,898 | +2% | 1 | 1 | 0% | 3,052 | 2,999 | -2% | 0 | 0 | — |
▸case-11 Our web application stores user authentication sessions in local server memory. When traffic spikes and auto-scaling adds new instances, users get randomly logged out because stickiness fails. A developer suggests forcing permanent sticky sessions on the load balancer as the permanent architecture fix. Evaluate this and propose a stateless architecture. | pass→pass | 16,136 | 22,692 | +41% | 1 | 1 | 0% | 2,805 | 3,674 | +31% | 0 | 0 | — |
▸case-12 An enterprise financial client requires our cloud architecture to support a Recovery Point Objective (RPO) under 1 minute and Recovery Time Objective (RTO) under 15 minutes. The team suggests taking nightly database snapshots to S3 as the sole backup strategy. Evaluate this plan against the stated RPO/RTO metrics and detail an appropriate database backup/replication design. | pass→pass | 16,545 | 33,577 | +103% | 1 | 1 | 0% | 2,998 | 3,609 | +20% | 0 | 0 | — |
▸case-14 In a globally distributed multi-region database deployment across US, EU, and Asia, management demands zero latency across all regions alongside 100% immediate global consistency and continuous availability during network partition events. Analyze this requirement using the CAP theorem and explain the architectural trade-off. | pass→pass | 17,913 | 22,958 | +28% | 1 | 1 | 0% | 3,105 | 4,211 | +36% | 0 | 0 | — |
▸case-15 Our monolithic frontend repository is maintained by 12 independent product engineering teams who constantly block each other's deployments and git merges. A senior developer suggests creating a shared mono-component library that all teams must modify in lockstep. Evaluate this and propose an architectural frontend decomposition pattern. | pass→pass | 16,580 | 24,712 | +49% | 1 | 1 | 0% | 2,875 | 4,306 | +50% | 0 | 0 | — |
▸case-16 Our social networking platform needs to calculate 4th-degree friend connections and recommendation paths across 50 million users. The team is trying to build recursive SQL join queries on a relational table, resulting in query times over 30 seconds. Evaluate this relational approach and recommend an appropriate database model. | pass→pass | 16,610 | 23,639 | +42% | 1 | 1 | 0% | 2,876 | 4,278 | +49% | 0 | 0 | — |
▸case-17 Our internal microservices communicate over unencrypted HTTP behind a VPN perimeter, trusting all traffic that originates inside the local network. Management assumes the internal network is completely secure. Perform an architectural review and recommend a modern network security architectural model. | pass→pass | 20,063 | 18,477 | -8% | 1 | 1 | 0% | 2,986 | 3,682 | +23% | 0 | 0 | — |
▸case-18 Users occasionally double-click the 'Pay Now' button, or network retries resend payment requests, causing duplicate charges in our billing service. The engineering team suggests adding a frontend JavaScript alert disabling the button after the first click. Evaluate this solution from an architectural reliability perspective and propose a server-side pattern. | pass→pass | 14,678 | 18,354 | +25% | 1 | 1 | 0% | 2,526 | 3,522 | +39% | 0 | 0 | — |
▸case-19 Our compliance team requires a complete, tamper-evident audit history of every modification ever made to financial ledger accounts. The current system performs in-place SQL UPDATE statements on account balance rows. Write an Architecture Decision Record (ADR) proposing an event sourcing architecture. | pass→pass | 17,578 | 26,155 | +49% | 1 | 1 | 0% | 3,161 | 4,686 | +48% | 0 | 0 | — |
▸case-20 We are onboarding non-technical stakeholders to our new online pharmacy platform. A developer gave them a 50-page UML sequence diagram detailing class methods. Produce a high-level System Context diagram representation in Mermaid syntax suitable for executive overview. | pass→pass | 12,084 | 12,686 | +5% | 1 | 1 | 0% | 2,100 | 2,404 | +14% | 0 | 0 | — |
▸case-21 Our analytics processing worker pool shares the same database connection pool as our core customer-facing checkout API. When automated nightly analytics queries run, they exhaust all DB connections, bringing down customer checkout. The dev team wants to increase the database max connection limit from 100 to 1000. Evaluate this and propose an architectural isolation strategy. | fail→pass | 15,440 | 16,481 | +7% | 1 | 1 | 0% | 2,673 | 3,068 | +15% | 0 | 0 | — |
▸case-22 I am getting a SyntaxError in my Python script: `Def calculate_total(items): return sum(items)`. Fix the code and explain what was wrong with the keyword. | pass→pass | 3,460 | 2,885 | -17% | 1 | 1 | 0% | 509 | 524 | +3% | 0 | 0 | — |
▸case-23 Write a PostgreSQL SQL migration script to add a non-null column `updated_at` with default `NOW()` to an existing `users` table without locking table reads for long periods. | fail→fail | 13,258 | 12,899 | -3% | 1 | 1 | 0% | 2,359 | 2,567 | +9% | 0 | 0 | — |
▸case-24 My Dockerfile fails to build on step 4 with `npm: command not found` after running `FROM alpine:latest`. Fix the Dockerfile commands to install Node.js and npm. | pass→pass | 4,130 | 4,222 | +2% | 1 | 1 | 0% | 752 | 905 | +20% | 0 | 0 | — |