Your path

Step 1
What really happens when you press F5~2 h
Step 2
Value and reference types: the stack, the heap and boxing~2 h · by the author’s design, after “What really happens when you press F5”
Step 3 · by the author’s design, after “Value and reference types: the stack, the heap and boxing”inside a rung the order is up to you
Memory and lifetime: the garbage collector, IDisposable, using~2 h
class, struct, record: what to declare data with~2 h
Strings: immutability, interning, StringBuilder, Span~1.5 h
Step 4
Equality, hashing and comparison: a contract that is easy to break~2 h · by the author’s design, after “class, struct, record: what to declare data with”
null: nullable types, nullable reference annotations and what to do about them~1.5 h · by the author’s design, after “class, struct, record: what to declare data with”
Span, Memory, ref struct and how to measure~2 h · by the author’s design, after any one of these: “Value and reference types: the stack, the heap and boxing”, “Strings: immutability, interning, StringBuilder, Span”
Encapsulation and construction: an object that cannot be assembled wrongly~2 h · by the author’s design, after “class, struct, record: what to declare data with”
Step 5 · ~2 h
Pattern matching, tuples, deconstructionby the author’s design, after any one of these: “class, struct, record: what to declare data with”, “null: nullable types, nullable reference annotations and what to do about them”
Inheritance and polymorphism: virtual, override, new, sealedby the author’s design, after “Encapsulation and construction: an object that cannot be assembled wrongly”
Delegates, lambdas, closures, eventsby the author’s design, after “Encapsulation and construction: an object that cannot be assembled wrongly”
Exceptions: what they are and what they are notby the author’s design, after “Encapsulation and construction: an object that cannot be assembled wrongly”
Step 6
Interfaces: the contract, explicit implementation, DIM~1.5 h · by the author’s design, after “Inheritance and polymorphism: virtual, override, new, sealed”
async/await: what it is and what it is not~2.5 h · by the author’s design, after “Delegates, lambdas, closures, events”
Step 7 · ~2 h
Generics: constraints, reification, varianceby the author’s design, after “Interfaces: the contract, explicit implementation, DIM”
Data at the boundary: JSON, files and streams, dates and timesby the author’s design, after any one of these: “Exceptions: what they are and what they are not”, “async/await: what it is and what it is not”
Concurrency: lock, Lock, Interlocked, SemaphoreSlim, Channel, Parallelby the author’s design, after “async/await: what it is and what it is not”
SRP: one reason to changeby the author’s design, after “Interfaces: the contract, explicit implementation, DIM”
Step 8 · ~2 h
Metadata: reflection, attributes, source generatorsby the author’s design, after any one of these: “What really happens when you press F5”, “Generics: constraints, reification, variance”
Collections: choosing a data structure and its costby the author’s design, after “Generics: constraints, reification, variance”
OCP: open for extension, closed for modificationby the author’s design, after “SRP: one reason to change”
Step 9 · ~2 h
LINQ: deferred execution, yield, IQueryableby the author’s design, after “Collections: choosing a data structure and its cost”
LSP: a subtype must be substitutableby the author’s design, after “OCP: open for extension, closed for modification”
Step 10
ISP: clients are not forced to depend on what they don't need~1.5 h · by the author’s design, after “LSP: a subtype must be substitutable”
Step 11
DIP and dependency injection~2.5 h · by the author’s design, after “ISP: clients are not forced to depend on what they don't need”
Step 12 · ~2 h
Creational patterns: who creates objects and howby the author’s design, after “DIP and dependency injection”
Structural patterns: how to assemble objects into a wholeby the author’s design, after “DIP and dependency injection”
Behavioral patterns: who calls whom and whenby the author’s design, after “DIP and dependency injection”, “Delegates, lambdas, closures, events”
The host, DI in practice, configuration, loggingC# в приложении · by the author’s design, after “DIP and dependency injection”
Step 13 · ~2 h
Applied .NET patterns: Repository, Options, CQRS, Resultby the author’s design, after 2 of these: “Creational patterns: who creates objects and how”, “Structural patterns: how to assemble objects into a whole”, “Behavioral patterns: who calls whom and when”
Minimal API: the pipeline, binding, validation, errorsC# в приложении · by the author’s design, after “The host, DI in practice, configuration, logging”
HttpClient, resilience and background jobsC# в приложении · by the author’s design, after “The host, DI in practice, configuration, logging”, “async/await: what it is and what it is not”
EF Core without illusionsC# в приложении · by the author’s design, after “The host, DI in practice, configuration, logging”, “LINQ: deferred execution, yield, IQueryable”
Step 14
Finale: testability and talking about architecture out loud~2.5 h · by the author’s design, after “Applied .NET patterns: Repository, Options, CQRS, Result”, “async/await: what it is and what it is not”
Shipping to Azure: App Service, secrets, managed identity~2 h · C# в приложении · by the author’s design, after “Minimal API: the pipeline, binding, validation, errors”
Step 15 · ~2 h
What's new in C# 13 and 14 and how interviewers ask about itby the author’s design, after “Finale: testability and talking about architecture out loud”
Testing a service: from the unit to HTTPC# в приложении · by the author’s design, after “The host, DI in practice, configuration, logging”, “Finale: testability and talking about architecture out loud”
Examfinal · in the browser, without the assistantclosed · enrol on the course

0 of 38 units done · ~63.5 h without the optional units, ~75.5 h with them

HttpClient, resilience and background jobs

What the unit teaches

Explain why new HttpClient() per request exhausts ports while an eternal static client doesn't see DNS changes, and choose between IHttpClientFactory and a long-lived client with PooledConnectionLifetime
Register named and typed clients, understand HandlerLifetime and handler rotation, and not hold a typed client in a singleton
Write your own DelegatingHandler (retries, logging) and predict how the order of handler registration changes behavior
Choose resilience strategies — retry with exponential backoff and jitter, circuit breaker, per-attempt and overall timeouts — and name their cost: retrying a non-idempotent POST, a retry storm
Write a BackgroundService that doesn't bring down the host: per-iteration error handling, PeriodicTimer with TimeProvider, a scope per iteration, the stopping token passed to the HTTP call, a work queue on Channel<T>

This unit is open to those enrolled

Enrolment is free — it is what lets the server remember your progress between sessions.