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FastAPI VS D (Programming Language)

Compare FastAPI VS D (Programming Language) and see what are their differences

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FastAPI logo FastAPI

FastAPI is an Open Source, modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints.

D (Programming Language) logo D (Programming Language)

D is a language with C-like syntax and static typing.
  • FastAPI Landing page
    Landing page //
    2023-05-14
  • D (Programming Language) Landing page
    Landing page //
    2023-05-09

FastAPI features and specs

  • High Performance
    Built on Starlette and Pydantic, FastAPI is one of the fastest frameworks for Python, providing high performance due to its asynchronous request handling.
  • Automatic Interactive API Documentation
    FastAPI automatically generates interactive API documentation via Swagger UI and ReDoc, which are very helpful for development and testing.
  • Type Checking and Validation
    With Pydantic models and Python type hints, FastAPI provides automatic data validation and type checking, reducing the chance of runtime errors.
  • Ease of Use
    Its syntax and design make it easy to learn for Python developers, offering a smooth development experience while reducing boilerplate code.
  • Asynchronous Support
    FastAPI supports asynchronous programming, allowing for better performance for I/O-bound operations, making it optimal for handling many simultaneous connections.
  • Extensive Documentation
    It has comprehensive and well-structured documentation, which is very useful for both beginners and advanced users.
  • Community and Ecosystem
    FastAPI has a growing community and ecosystem, with many plugins and integrations available to extend its functionality.

Possible disadvantages of FastAPI

  • Learning Curve for Asynchronous Programming
    Although FastAPI itself is easy to learn, grasping the concepts of asynchronous programming in Python can be challenging for beginners.
  • Complex Dependencies
    Using Pydantic for advanced validation can make the request models complex, requiring a deeper understanding of Pydantic and its functionalities.
  • Early Stage Libraries
    Some third-party libraries and extensions specifically tailored for FastAPI might still be in early stages of development and lack long-term stability.
  • Limited Real-World Examples
    Although the documentation is extensive, there might be limited real-world examples and case studies readily available compared to more mature frameworks.
  • Deployment Complexity
    Deploying FastAPI applications might be more complex in comparison to traditional synchronous frameworks, mainly due to the need for asynchronous server setups.

D (Programming Language) features and specs

  • Performance
    D is designed to be a high-performance systems programming language, offering performance comparable to C and C++ through native machine code compilation.
  • Expressiveness
    D features a rich standard library and modern language constructs, such as garbage collection, first-class arrays, and advanced templating, making it easier to write expressive and maintainable code.
  • Memory Safety
    D offers optional garbage collection along with manual memory management. This hybrid approach can help in developing safer applications by reducing memory-related errors.
  • Interoperability
    D can easily interoperate with C API, enabling seamless integration with existing C libraries and systems. It also supports better C++ interoperability compared to other languages.
  • Built-in Unit Testing
    D has built-in support for unit tests, allowing developers to write and run tests as part of the language itself, facilitating test-driven development.
  • Concurrency
    D offers built-in concurrency support with message passing, similar to the actor model found in languages like Erlang, making it easier to write concurrent and parallel programs.

Possible disadvantages of D (Programming Language)

  • Adoption
    D is not as widely adopted as other languages like C, C++, or Java. This limited adoption means fewer libraries, frameworks, and community support.
  • Toolchain Maturity
    While D's compilers and tools have improved over the years, they may still lack the maturity and feature set of more established languages, which can affect developer productivity.
  • Learning Curve
    D's richness and combination of paradigms (such as imperative, object-oriented, and functional programming) can present a steep learning curve for new developers.
  • Garbage Collection
    Although D offers optional garbage collection, its reliance on it for memory safety might be seen as a drawback for real-time system development where deterministic memory management is crucial.
  • Ecosystem
    The ecosystem for D is less vibrant compared to more popular languages, leading to potentially fewer third-party libraries, tools, and resources.
  • Standard Library Documentation
    The standard library documentation can be inconsistent or less comprehensive compared to other languages, making it difficult for developers to fully utilize all features of the language.

Analysis of FastAPI

Overall verdict

  • FastAPI is widely regarded as a good choice, especially for applications that require high performance, scalability, and modern Python features. It is suitable for both simple and complex projects, making it a versatile tool in the web development ecosystem.

Why this product is good

  • FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.7+ based on standard Python type hints. It is built on top of Starlette for web framework capabilities and Pydantic for data validation and settings management. FastAPI is known for its excellent performance, automatic generation of interactive API documentation (with Swagger and Redoc), and support for asynchronous programming. Developers appreciate its ease of use, detailed documentation, and helpful error messages.

Recommended for

  • Developers building RESTful APIs
  • Teams looking for a high-performance ASGI-based web framework
  • Projects that require asynchronous programming capabilities
  • Applications needing automatic generation of interactive API documentation
  • Python developers who prefer utilizing type hints for code clarity and validation

Analysis of D (Programming Language)

Overall verdict

  • Overall, D is a solid programming language choice that balances performance with productivity. It may not be as widely adopted as some other languages, but it has a dedicated community and continues to evolve, making it a viable option for various programming tasks.

Why this product is good

  • The D programming language is considered good by many developers for various reasons. It combines the performance and low-level control of C/C++ with the expressive power and ease of use found in modern languages. D offers features like garbage collection, first-class functions, and compile-time function execution, providing both speed and flexibility. Its interoperability with C, the convenience of a powerful standard library (Phobos), and the availability of packages via the DUB package manager make it a practical choice for systems programming, application development, and rapid prototyping.

Recommended for

  • System programming enthusiasts looking for an alternative to C/C++
  • Developers interested in writing high-performance applications
  • Programmers who appreciate modern language features and strong community support
  • Projects requiring seamless C integration
  • Individuals looking for a language that supports easy code maintenance and scalability

FastAPI videos

FastAPI from the ground up

More videos:

  • Tutorial - 30 Days of Python - Day 14 - Web App with Flask, FastAPI, ngrok, and Invictify - Python TUTORIAL
  • Review - [PT] Python - API com FastAPI - Chat | twitch.tv/codeshow

D (Programming Language) videos

D Language Tutorial

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User comments

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Reviews

These are some of the external sources and on-site user reviews we've used to compare FastAPI and D (Programming Language)

FastAPI Reviews

  1. Kurslog team
    ยท Working at Kurslog ยท

    When our backend team needs to build services for data parsing, aggregators, or high-load APIs, FastAPI is our absolute go-to choice. It completely lives up to its name-development speed is outstanding.

    The combination of Pydantic for data validation and built-in async support keeps our shared codebase clean, strictly typed, and reliable. But the biggest highlight for our cross-functional team is the automatic generation of interactive OpenAPI (Swagger) documentation. Our frontend and mobile developers no longer have to wait for backend engineers to manually update API docs; everything stays perfectly in sync automatically. It has drastically improved our team's communication and delivery speed.

    ๐Ÿ Competitors: Django, Flask, ExpressJS, Nest.js, Spring Boot
    ๐Ÿ‘ Pros:    Blazing fast performance (on par with nodejs and go)|Native asynchronous support out of the box|Automatic, interactive documentation generation (swagger/redoc)|Strict typing and data validation with pydantic
    ๐Ÿ‘Ž Cons:    Smaller plug-and-play ecosystem compared to older frameworks like django|Requires our architects to design the project structure and directory layout from scratch

The 20 Best Laravel Alternatives for Web Development
FastAPI, as the name hints, is a swift mover. Built on Starlette, itโ€™s all about speed and performance with Python. Crafting API masterpieces at the speed of light, now thatโ€™s something.
25 Python Frameworks to Master
Since its release in 2018, it has rapidly gained popularity due to its great performance and simplicity. In fact, according to PyPi Stats, FastAPI has over 9 million monthly downloads, surpassing even full-stack frameworks like Django.
Source: kinsta.com
3 Web Frameworks to Use With Python
myapp/ is the main directory of your FastAPI application. It includes all the other files and directories needed for the application.static/ is a directory used to store static assets such as CSS, JavaScript, and image files. These assets are served directly by the web server and are typically used to add visual styling and interactivity to the application.css/, img/, js/...
Best Alternatives to FastAPI App Free for Windows (2021)
FastAPI Alternative โ€“ So many alternatives app to FastAPI that you must to know out there. And, looking for an ideal software was not easy matter. Lucky you, at this page you can find the best replacement app for FastAPI. So what you are waiting for, get the latest FastAPI alternative app for Windows 10 from this page.
Top 5 Back-End Frameworks to Consider for Web Development in 2021
FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints. It is fast when compared to other major Python frameworks like Flask and Django. FastAPI gives great flexibility to fulfill businessesโ€™ API needs in todayโ€™s evolving world.

D (Programming Language) Reviews

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Social recommendations and mentions

Based on our record, FastAPI should be more popular than D (Programming Language). It has been mentiond 311 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

FastAPI mentions (311)

  • Shipping Sovereign SDK: Cryptographic Forensic Receipts and the End of the AI "Prose Tax"
    The Sovereign SDK is a Python-native framework designed to minimize prose overhead while generating ironclad, cryptographic execution receipts for AI agents, complete with drop-in FastAPI/Starlette ASGI middleware. - Source: dev.to / about 1 month ago
  • 5-Minute AI Jobs and Closed Tabs โ€” Why We Built Replay-Then-Tail SSE
    We had a feature in production where a single user request could run for five-plus minutes โ€” fetch documents, chunk them, hit an LLM per chunk, synthesize a final answer. We did the obvious thing first: a FastAPI handler that ran the pipeline and streamed progress back to the browser over Server-Sent Events. - Source: dev.to / 2 months ago
  • FastAPI With LangChain and MongoDB
    FastAPI is a Python framework for building APIs quickly, efficiently, and with very little code. - Source: dev.to / 3 months ago
  • I Built A " CrowdSense AI " : A Scalable, Context-Aware Platform for Smart Stadiums
    Backend: Python-based FastAPI for its asynchronous I/O capabilities and rapid JSON serialization. - Source: dev.to / 3 months ago
  • Async PyMongo in FastAPI
    FastAPI is a high-performance web framework that is production-ready and designed for building APIs in python, with roots embedded in asynchronous programming. It embraces Pythonโ€™s asyncio model as its core principle rather than treating it as optional. This design choice gives FastAPI leverage for I/O bound workloads such as db access, external API calls and real-time data streaming. - Source: dev.to / 3 months ago
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D (Programming Language) mentions (60)

  • Ask HN: What is your (AI) dev tech stack / workflow? (June 2026)
    I've spent 2 weeks (2-4h per day) to make D language[1] version of Sciter SDK [2] Choice of AI "tooling" was by accident - typed something like "how to define copy constructor in D for custom structure" in Microsoft's Copilot in Edge browser that gives context for AI. The answer was good enough for me and so I went with it further. [1] D language HQ : https://dlang.org/. - Source: Hacker News / about 1 month ago
  • Rue: Higher level than Rust, lower level than Go
    > Mostly, I am not really trying to compete with C/C++/Rust on speed, but I'm not going to add a GC either. So I'm somewhere in there. Out of curiosity, how would you compare the goals of Rue with something like D[0] or one of the ML-based languages such as OCaml[1]? 0 - https://dlang.org/ 1 - https://ocaml.org/. - Source: Hacker News / 7 months ago
  • Pony: An actor-model, capabilities-secure, high-performance programming language
    The D language home page has something similar with a drop down with code examples https://dlang.org/. - Source: Hacker News / 11 months ago
  • Show HN: D++lang โ€“ A new systems programming language with Python-like syntax
    What is this? There's a lot of red flags here. * The name "D" for a programming language was taken in 1999: https://dlang.org/. - Source: Hacker News / about 1 year ago
  • Koto Programming Language
    >For me the biggest gap in programming languages is a rust like language with a garbage collector, instead of a borrow checker. I cannot agree more that's the much needed sweet spot/Goldilock/etc. Personally I have been advocating this approach for some times. Apparently the language is already widely available and currently has stable and wide compiler support including the venerable GNU compiler suite (GDC). It... - Source: Hacker News / over 1 year ago
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What are some alternatives?

When comparing FastAPI and D (Programming Language), you can also consider the following products

Flask - a microframework for Python based on Werkzeug, Jinja 2 and good intentions.

C++ - Has imperative, object-oriented and generic programming features, while also providing the facilities for low level memory manipulation

ExpressJS - Sinatra inspired web development framework for node.js -- insanely fast, flexible, and simple

Nim (programming language) - The Nim programming language is a concise, fast programming language that compiles to C, C++ and JavaScript.

Django - The Web framework for perfectionists with deadlines

V (programming language) - Simple, fast, safe, compiled language for developing maintainable software.