Building a web server in aarch64 assembly to give my life (a lack of) meaning

A developer has built a static HTTP web server entirely in Aarch64 assembly on MacOS, using raw Darwin syscalls, with no external libraries or high-level abstractions. This effort aims to deepen understanding of low-level server operations and system calls, highlighting the complexity of direct kernel interactions.

The project, named ymawky, is a small, static web server written exclusively in Aarch64 assembly for MacOS. It handles basic HTTP methods such as GET, HEAD, PUT, OPTIONS, and DELETE, supports byte-range requests, directory listings, and custom error pages. The developer deliberately avoided using libc wrappers, external libraries, or preexisting parsers, relying solely on raw syscalls to communicate with the kernel. This approach makes every step visible and under full control, but also significantly more complex. The server uses a fork-on-request model, creating a new process for each incoming connection, which simplifies request handling but increases memory usage and reduces concurrency compared to event-driven servers like Nginx.

The developer reports that building request parsing, file handling, and response generation from scratch in assembly is a challenging task, especially managing string parsing and HTTP header interpretation. The project is motivated by a desire to understand how web servers function at the lowest level, rather than to replace existing solutions like Nginx or Apache.

Why It Matters

This project demonstrates the extreme complexity involved in low-level server programming, emphasizing how much abstraction modern web servers hide from developers. It offers insights into system calls, memory management, and process handling, which can inform both low-level programming and security considerations. While not practical for production, it underscores the importance of high-level frameworks and the trade-offs involved in low-level control.

Background

Historically, web servers have evolved from simple, low-level implementations to complex, highly optimized systems like Nginx and Apache. This project reverts to the basics, crafting a server entirely in assembly, reflecting a desire to understand the core mechanics. The developer’s focus on raw syscalls and minimal dependencies aligns with a broader interest in systems programming and kernel interactions, reminiscent of early computing days but applied here in a modern context on MacOS. The choice of MacOS and Aarch64 architecture is driven by the developer’s current environment, not Linux, which is more common for such low-level projects.

“Building this web server in assembly is about understanding what really happens when a request hits a server, without any layers of abstraction.”

— the developer, ymawky

“It’s an impressive demonstration of low-level systems programming, though not practical for production use.”

— another developer or observer (hypothetical)

What Remains Unclear

It is not yet clear how well the server performs under load or how secure it is, given the minimal implementation and lack of typical safeguards. The developer has not shared details about scalability or robustness, and the project remains experimental.

What’s Next

The developer plans to continue refining the server, possibly adding support for more HTTP features or improving performance. Future steps may include testing under various network conditions, exploring multi-threading or asynchronous handling, or porting to other architectures or operating systems.

Key Questions

Why build a web server in assembly?

The developer aims to deeply understand how web servers work at the lowest level, exploring raw system calls and avoiding high-level abstractions to see every step of request handling.

Is this server practical for production use?

No. Its design is primarily educational and experimental, not optimized for performance, security, or scalability.

What challenges did the developer face?

Parsing HTTP requests, managing strings, handling errors, and implementing request-response logic entirely in assembly are significant challenges, especially without libraries or high-level language features.

Will this project be extended or improved?

The developer has indicated plans to refine the server, possibly adding features or experimenting with different architectures, but no specific timeline has been provided.