Drills

Concept questionHard~9 min

Use capacity, load shedding, and backpressure signals

Explains saturation signals and how systems shed, queue, throttle, or degrade before cascading failure.

.NETApplication InsightsASP.NET CoreAzure Service BusEF Core+4

Architecture scenarioMedium~10 min

Use correlation IDs and logging scopes in ASP.NET Core APIs

Use correlation IDs, structured logs, and logging scopes to make API failures traceable in production.

.NETASP.NET CoreEF CoreSQL

Use DbContext pooling without leaking request state

Uses EF Core context pooling only when reusable context state, tenant isolation, and underlying connection state are controlled and tested.

.NETAmazon SQSAzure Service BusRabbitMQ

Use delayed and scheduled messages

Explains delayed delivery, scheduled work, reminders, retry timing, cancellation, and clock-related trade-offs.

.NETASP.NET CoreEF CoreSQL

Use EF Core compiled queries on hot paths

Explains when EF Core compiled queries help, what they do not fix, and how to measure their value.

Debugging scenarioMedium~10 min

Use EF Core query tags and correlation for production debugging

Explains how query tags, request correlation, and telemetry help connect slow SQL back to code paths.

.NETApplication InsightsASP.NET CoreEF CoreSQL

.NETASP.NET CoreEF CoreSQL

Use ExecuteUpdate instead of loading entities for bulk changes

Explains when set-based EF Core updates are better than loading entities and where lifecycle behavior can differ.

Architecture scenarioHard~12 min

Use If-Match preconditions to prevent lost updates

Connects HTTP preconditions to atomic database concurrency checks and honest 412 or 428 API behavior.

.NETASP.NET Core

Architecture scenarioMedium~10 min

Use immutable snapshots instead of shared mutable state

Redesigns read-heavy shared state so readers observe a complete version without coordinating every access through a lock.

.NETC#

Comparison questionEasy~5 min

Use logs, metrics, and traces for API diagnosis

Explains the different diagnostic roles of logs, metrics, and traces during backend production issues.

.NETApplication InsightsASP.NET CoreOpenTelemetry

Architecture scenarioMedium~10 min

Use OpenAPI as an API contract

Use OpenAPI for API design, client integration, testing, and contract review in ASP.NET Core services.

Architecture scenarioHard~12 min

Use read models for complex API screens

Explains read models for complex API screens with practical .NET data-access examples and production trade-offs.

.NETC#EF CoreSQL

.NETASP.NET CoreRedisStackExchange.Redis

Use Redis counters for API rate limiting

Explains Redis-backed rate-limit counters, atomic increments, windows, identity keys, and fallback behavior.

Concept questionHard~9 min

Use Redis locks only with clear lease boundaries

Explains the risks of Redis-based distributed locks and when database constraints, queues, or idempotency are safer.

.NETASP.NET CoreRedisStackExchange.Redis

Comparison questionEasy~5 min

Use, Run, and Map in the ASP.NET Core middleware pipeline

Explains middleware continuation, terminal delegates, path branches, short-circuiting, and two-way request and response flow.

Use security headers, TLS, and cookie flags correctly

Explains HTTPS, HSTS, secure cookies, HttpOnly, SameSite, no-store, and practical API/browser security hardening.

.NETASP.NET CoreJWT

.NETApplication InsightsASP.NET CoreOpenTelemetry

Use structured logs without leaking sensitive data

Explains structured logging fields, safe context, redaction, event naming, and avoiding secret or personal-data leaks.

Architecture scenarioHard~12 min

Use the inbox pattern to deduplicate consumed messages

Makes consumer-side deduplication atomic with the business change while supporting concurrent delivery, retention, replay, and failed processing.

.NETAmazon SQSAzure Service BusRabbitMQ

Using SemaphoreSlim for concurrency limits

Use SemaphoreSlim to bound concurrent asynchronous work without blocking threads unnecessarily.

Using Task.WhenAll for independent I/O

Use Task.WhenAll to run independent asynchronous I/O operations concurrently while handling exceptions, cancellation, and dependency limits.

Coding problemEasy~15 min

Validate a date range request

Implements a small validation helper for date ranges with clear error messages.

.NETC#

Validate JWTs and trust claims carefully

Explains JWT validation, trusted issuers, audiences, expiration, signing keys, claims, and server-side authorization boundaries.

.NETASP.NET CoreJWT

Concept questionEasy~5 min

Value types, reference types, and parameter passing in C#

Explains what is copied when values and object references are assigned or passed, including the explicit effect of ref, out, and in.

.NETC#