Cool Libraries For ASP.NET Core Tool-Belt

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.NET Core is a well-known and robust open-source framework for developing software applications of nearly all kinds. It offers a vast, but well-organized ecosystem of libraries and tools to help developers streamline and ease out their development process. In this context, several popular .NET libraries have gained significant traction among developers – offering a range of rather complex functionalities and simplifying common tasks.

Without further ado, let’s put forth some of the very popular and useful libraries for you:


Micorsoft ASP.NET Core Authentication JWTBearer

JSON Web Token a.k.a JWT is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. JWTs are commonly used for authentication and authorization purposes in web applications and APIs.

JWTs are typically used in the following flow:

Authentication: A user provides their credentials (such as username and password) to the server.
Server Validation: The server validates the credentials and generates a JWT.
JWT Issuance: The server signs the JWT using a secret key and sends it back to the client.
Token Usage: The client includes the JWT in subsequent requests (usually in the Authorization header) to access protected resources.
Token Verification: The server receives the JWT, verifies its integrity and signature, and extracts the claims to determine the user’s identity and permissions.

Using Micorsoft ASP.NET Core Authentication JWTBearer build a solid JWT authentication in your ASP.NET Core Web API with a cryptographically secure JWT generation and validation. Being a standardized way to transmit the token within the HTTP requests, it makes it compatible with various programming languages, frameworks, and libraries that support JWT authentication.


Entity Framework Core

Entity Framework Core (EF Core) is an open-source, cross-platform object-relational mapping (ORM) library provided by Microsoft. It is a modern, lightweight, and extensible version of the Entity Framework (EF) framework specifically designed for .NET Core and .NET Standard.

EF Core enables developers to interact with relational databases using .NET objects, eliminating the need for writing low-level database-specific code. It simplifies data access and provides a high-level abstraction over the database, allowing developers to focus on application logic rather than manual data access tasks.

Key features and benefits of Entity Framework Core include:

Object-Relational Mapping (ORM): EF Core maps database tables to .NET objects, providing a seamless way to perform CRUD (Create, Read, Update, Delete) operations on
the database using familiar programming constructs.

Data Modeling: EF Core allows developers to define their data model using classes (entity classes) and their relationships (associations). These classes and relationships are then mapped to database tables and foreign key constraints, respectively.

LINQ Support: EF Core provides LINQ (Language Integrated Query) support, allowing developers to use LINQ expressions to query and manipulate data. This enables the use of strongly-typed queries, making the code more readable, maintainable, and less prone to errors.

Database Provider Support: EF Core covers multiple database providers, including Microsoft SQL Server, MySQL, PostgreSQL, SQLite, and more. It provides a plugg-able architecture that allows you to choose the database provider that best suits your application’s needs.

Migrations: EF Core includes a migrations feature that enables developers to easily manage database schema changes over time. Migrations allow for database schema updates without losing data or recreating the entire database.

Cross-Platform and Cross-Database: EF Core is designed to work across different platforms (Windows, macOS, Linux) and supports various database systems, making it suitable for building applications that need to run on different operating systems or target multiple database platforms.



Newtonsoft.Json is a high-performance library to easily convert between JSON and .NET objects, create and parse JSON objects, query JSON objects using LINQ and provide formatting HTTP responses.

Newtonsoft.Json is a popular and widely used JSON serialization and de-serialization library for .NET platforms. It is developed by James Newton-King and provides comprehensive support for working with JSON data in .NET applications.

Newtonsoft.Json, also known as Json.NET, offers a range of features and functionalities that simplify JSON processing. Some key features include:

Serialization and De-serialization: Json.NET allows you to convert .NET objects to JSON (serialization) and JSON back to .NET objects (de-serialization). It provides flexible options to control the serialization process, handle complex object graphs, and handle various data types, including custom types.

LINQ to JSON: Json.NET provides a LINQ-like querying API for querying and manipulating JSON data. This allows you to easily navigate, extract, filter, and modify JSONstructures using familiar LINQ syntax.

JSON Schema: Json.NET supports working with JSON Schema, a specification that describes the structure and validation rules for JSON data. It allows you to validate JSON against a schema, generate JSON schemas from .NET types, and perform various schema-related operations.

Customization and Extensibility: Json.NET offers extensive customization options through attributes, converters, and settings. You can control how objects are serialized, handle special cases, and extend the library’s behavior to accommodate specific requirements.

Performance and Compatibility: Json.NET is known for its performance and has been optimized to handle large JSON payloads efficiently. It supports various .NET platforms, including .NET Framework, .NET Core, and Xamarin, making it widely compatible with various development environments.


SwashBuckle – ASP.NET Core Swagger

Swashbuckle is a library for .NET that integrates with ASP.NET Web API projects to generate interactive documentation (API documentation) and provide a user-friendly interface for testing and exploring APIs. It leverages the capabilities of the Swagger tooling, which is an open-source framework for designing, building, and documenting RESTful APIs.

Swashbuckle, also known as Swagger for ASP.NET Web API, offers the following key features:

Automatic Documentation Generation: Swashbuckle reads the API controllers, models, and XML comments within your ASP.NET Web API project and generates comprehensive documentation in the Swagger/OpenAPI format. This documentation includes details about available endpoints, request/response schemas, supported HTTP methods, parameters, headers, and more.

Interactive API Explorer: Swashbuckle provides an interactive web-based UI (User Interface) called Swagger UI that allows developers and API consumers to explore and test the API endpoints directly from their web browser. It offers a user-friendly interface to understand the API structure, make requests, view responses, and experiment with different input parameters.



Rely on a simple yet powerful, blazingly fast, configuration-based tool to handle the objects mapping for you. Supports fluent API, Nested Mappings, Immutable Collections.

Mapster is a lightweight, open-source, and versatile object mapping library for .NET applications. It simplifies the process of mapping objects between different types, allowing developers to efficiently transfer data between layers of their application, such as between database models, domain models, and
DTOs (Data Transfer Objects).

Key features and benefits of the Mapster library include:

Fluent and Code-Based Mapping Configuration: Mapster provides a fluent API and a code-based configuration approach for defining object mappings. This allows developers to explicitly define how properties should be mapped, handle complex mappings, and override default mapping conventions.

Automatic Mapping: Mapster offers automatic mapping capabilities, where it infers the mapping between properties based on naming conventions and data types. It can automatically map properties with the same names and compatible types without requiring explicit configuration.

Support for Complex Mapping Scenarios: Mapster supports complex mapping scenarios, including nested objects, collections, and inheritance hierarchies. It provides options for customizing the mapping behavior for specific properties or types, enabling fine-grained control over the mapping process.

Efficient and Performant: Mapster is designed to be efficient and performant, providing fast object mapping operations. It utilizes reflection and expression trees to optimize the mapping process and minimize performance overhead.

Support for Various .NET Platforms: Mapster supports multiple .NET platforms, including .NET Framework, .NET Core, and .NET Standard. This makes it suitable for a wide range of applications, regardless of the specific .NET platform being used.

Extensibility: Mapster offers extensibility points that allow developers to customize and extend its functionality. It provides hooks for custom type converters, value resolvers, and other mapping-related operations.


ASP.NET Core Fluent Validation

ASP.NET Core Fluent Validation is a popular library that provides a fluent and expressive way to perform validation in ASP.NET Core applications. It is built on top of the FluentValidation library, which is a widely used validation library for .NET.

ASP.NET Core Fluent Validation offers the following key features and benefits:

Fluent Validation Rules: With Fluent Validation, you can define validation rules using a fluent and expressive syntax. It allows you to specify rules for individual properties or groups of properties, such as required fields, string length limits, numeric ranges, regular expressions, custom validation logic, and more.

Automatic Validation: ASP.NET Core Fluent Validation integrates seamlessly with ASP.NET Core’s model binding process. It automatically triggers the validation of
incoming request models based on the defined validation rules. Validation errors can be easily accessed and handled in the application.

Custom Validation Messages: You can provide custom error messages for each validation rule, giving you full control over the error messages displayed to the user. The library supports localization, making it easier to display validation messages in various languages.

Cross-Property Validation: Fluent Validation supports cross-property validation, allowing you to define validation rules that depend on the values of multiple properties. This enables more complex validation scenarios, such as comparing values or ensuring consistency between related fields.

Integration with ASP.NET Core: ASP.NET Core Fluent Validation integrates smoothly with the ASP.NET Core ecosystem. It works well with the model binding, action filters, and middle-ware pipeline of ASP.NET Core, making it easy to include validation in your application’s request processing flow.

Testability: Fluent Validation provides testability features that allow you to unit test your validation rules. It offers a simple and intuitive API for setting up test scenarios, applying validation rules, and verifying the expected validation results.


ASP.NET Core Serilog

ASP.NET Core Serilog is a logging integration library that enables the use of the Serilog logging framework within ASP.NET Core applications. Serilog is a popular and flexible logging library for .NET applications, and ASP.NET Core Serilog provides seamless integration between Serilog and ASP.NET Core’s logging infrastructure.

With ASP.NET Core Serilog, you can configure Serilog as the logging provider for your ASP.NET Core application. It offers the following features and benefits:

Flexible Logging Configuration: ASP.NET Core Serilog allows you to configure Serilog using various methods, such as code-based configuration, JSON configuration files, environment variables, or other configuration sources supported by ASP.NET Core. This flexibility enables you to control the log output format, sink destinations (such as console, file, or external logging services), and logging levels.

Structured Logging: Serilog promotes structured logging, which means that log messages are enriched with structured data in the form of key-value pairs. This enables better analysis and filtering of log events, as well as integration with log aggregation and analysis tools.

Rich Log Filtering and Sink Options: Serilog offers powerful filtering capabilities, allowing you to control which log events are captured based on their properties, severity levels, or other criteria. It also provides various sinks (output destinations) to store log events, including files, databases, Elasticsearch, and
cloud-based logging services.

Extensibility: Serilog is highly extensible, and ASP.NET Core Serilog allows you to leverage this extensibility within your ASP.NET Core application. You can add custom enrichers, sinks, or other Serilog extensions to tailor the logging behavior according to your specific requirements.

Integration with ASP.NET Core’s Logging Abstraction: ASP.NET Core Serilog seamlessly integrates with ASP.NET Core’s built-in logging abstraction. This means that you can continue using the standard logging APIs provided by ASP.NET Core, such as ILogger, while benefiting from the powerful features and configurability of Serilog.


ASP.NET Core MVC Versioning

“Microsoft.AspNetCore.Mvc.Versioning” library provides versioning support for ASP.NET Core MVC applications. This library allows you to version your API endpoints based on different criteria, such as URL path, query string, or headers.

By using the Microsoft.AspNetCore.Mvc.Versioning library, you can easily implement versioning in your ASP.NET Core MVC application, enabling you to make backward-compatible changes to your APIs without breaking existing client applications.

To use this library, you can install the “Microsoft.AspNetCore.Mvc.Versioning” NuGet package in your project. Once installed, you can configure versioning options in your Startup class and decorate your API controllers or actions with versioning attributes to indicate the supported versions.



Refit is a popular library for creating type-safe HTTP clients in .NET. It simplifies the process of consuming RESTful APIs by automatically generating API interfaces based on specified contracts or interfaces. Refit uses the power of .NET’s HttpClient and provides a higher-level abstraction for making HTTP requests
and handling responses.

With Refit, you define an interface that represents the API endpoints you want to consume, and Refit generates an implementation of that interface at runtime. This implementation handles the HTTP communication, serialization, and deserialization of data, allowing you to interact with the API in a strongly typed manner.

Refit supports various HTTP verbs (GET, POST, PUT, DELETE, etc.), URL parameters, query parameters, request headers, and content serialization using libraries like Newtonsoft.Json or System.Text.Json.

To use Refit, you need to install the “Refit” NuGet package in your project. It’s worth noticing that Refit works efficiently with modern .NET frameworks like .NET Core and .NET 5/6.


StackExchange Redis

StackExchange.Redis is a popular open-source library for working with Redis, a high-performance in-memory data store. Redis is often used as a cache, message broker, or data structure server in various applications.

StackExchange.Redis library is specifically designed for .NET applications and provides a convenient and efficient way to interact with Redis using the .NET programming language. It is developed and maintained by the Stack Exchange team, known for their expertise in building large-scale web applications.

The library offers a rich set of features and abstractions to work with Redis. It provides a simple API to connect to a Redis server, send commands, and retrieve responses. It supports all major Redis data types, such as strings, lists, sets, sorted sets, hashes, and hyperlogs.

Some key features of StackExchange.Redis include:

Connection Management: It handles the management of Redis connections, including connection pooling, reconnecting in case of failures, and handling multiple servers in a Redis cluster.

Command and Pipeline Support: It allows you to send Redis commands to the server and retrieve responses. It also supports command pipelining, which enables batching of multiple commands to reduce network round-trips.

Pub/Sub (Publish/Subscribe) Support: It provides a straightforward way to publish messages to channels and subscribe to receive messages from channels.

Lua scripting: It supports executing Lua scripts on the Redis server, allowing you to perform complex operations in an atomic and efficient manner.

Asynchronous and Synchronous Operations: It offers both synchronous and asynchronous methods to interact with Redis, giving you flexibility in choosing the appropriate programming style for your application.



MediatR is a popular open-source library for implementing the Mediator pattern in .NET applications. The Mediator pattern is a behavioral design pattern that promotes loose coupling and simplifies communication between components by introducing a mediator object that encapsulates the interaction logic.

MediatR provides a mediator implementation that enables communication between different components (handlers) by sending requests (messages) and receiving responses. It follows the “Request-Response” model, where requests are sent to the mediator, and appropriate handlers are invoked to process the requests and return responses.

With MediatR, you define your application’s requests and corresponding handlers as separate classes. A request represents a message or a command that carries data, and a handler is responsible for processing that request. The mediator acts as a centralized component that receives requests and routes them to the appropriate handler.

Some key features and benefits of MediatR include:

Loose Coupling: MediatR helps decouple the sender of a request from the receiver by introducing a mediator, allowing components to communicate without having direct dependencies on each other.

Simplified Communication: It provides a clean and straightforward way to send requests and handle them with separate handlers, promoting a more organized and
maintainable codebase.

Separation of Concerns: By separating requests and handlers, MediatR helps in keeping the codebase focused on specific responsibilities and improves code modularity.

Pipeline Behavior: MediatR allows you to define pipeline behaviors that can intercept requests and responses, enabling cross-cutting concerns such as validation, logging, caching, and authorization to be added easily.

Asynchronous support: MediatR supports both synchronous and asynchronous request handling, allowing you to take advantage of asynchronous programming techniques to improve the performance and responsiveness of your application.

MediatR is available as a NuGet package and can be easily added to your .NET projects. It is widely used in various types of applications, including web applications, microservices, and domain-driven design (DDD) architectures, where the Mediator pattern provides a transparent and efficient way to handle communication and coordination between components.



xUnit.NET (or simply xUnit) is an open-source testing framework for the .NET infrastructure. It is a unit testing tool designed to support automated testing of .NET applications, enabling developers to write and execute tests against their code.

xUnit.NET is based on the xUnit testing framework family, which includes xUnit for various programming languages such as Java, Python, and Ruby. It follows the principles of simplicity, scalability, and flexibility to provide a robust and developer-friendly testing experience.

Some key features and notions of xUnit.NET include:

Test Classes and Test Methods: xUnit.NET organizes tests into classes and test methods, where each test method represents a specific scenario or behavior to be tested.

Test Lifecycle Management: xUnit.NET provides attributes that allow you to control the lifecycle of tests, such as setting up test fixtures before running tests and cleaning up resources afterward.

Test Assertions: It offers a rich set of assertion methods to verify expected outcomes and conditions in your tests. These assertions help you check whether the actual results match the expected values.

Test Runners: xUnit.NET supports various test runners, both within integrated development environments (IDEs) like Visual Studio and via command-line interfaces (CLIs). These runners discover and execute tests, generate test reports, and provide feedback on test results.

Test Data Theories: xUnit.NET supports data-driven testing using theories, where test methods can be parameterized with different inputs and expected outputs. This
enables testing different scenarios with a single test method.

Extensibility and Customization: xUnit.NET provides extensibility points that allow you to customize the test execution process, implement custom assertions, and integrate with other testing frameworks or tools.

Parallel Test Execution: xUnit.NET supports running tests in parallel, which can significantly speed up the test execution process, especially when running a large number of tests.


The mentioned libraries are analogous to a swiss army knife. You can confidently use them to fulfill various requirements of disparate natures. On the other hand, libraries coming from heterogeneous sources, having specific coding and interface structures of their own, are not supposed to adhere to specific standards and interfaces. This lack-of-compliance may give rise to memory usage issues, in-efficient code execution and sometime conflicting behavior. This is likely to happen if you choose to import and use excessive number of libraries in your project without dire need. Point to ponder is that use the libraries which are absolutely necessary for your particular requirements and prefer using your own and others’ well familiar piece of code for the little requirements you come across. Make your best efforts to keep your code loosely-coupled, consistent, uniformly-designed and, avoid using a bulldozer to swat a fly.

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