SwiftOS: A Custom Kernel in Embedded Swift Now Serves Its Own Website

A developer built SwiftOS, a hobby operating system written entirely in Embedded Swift for 64-bit ARM — kernel, drivers, TCP/IP stack, and userland tools all in Swift. It runs on a Hetzner Cloud ARM VM and serves its own website, swiftos.tech, over HTTPS: there's no Linux inside the guest, and nginx is statically linked against a custom syscall ABI and newlib port.

The system features a three-tier filesystem (an immutable signed base image, a RAM-backed scratch layer, and a persistent /data tier whose only durability guarantee is that fsync reaches disk), a capability-based security model instead of root, and a Swift-native TLS 1.3 stack currently used only by the ACME client rather than public traffic. Node.js runs jitless via V8's lite mode, since the kernel refuses RWX memory pages.

The project was built to probe how far Embedded Swift can go for low-level systems work, and its design draws more from mainframe traditions — immutable image discipline, recovery-oriented architecture — than from Unix conventions. About 91,000 lines of Swift went into it over 1,235 commits in two months, developed partly alongside a coding agent; the author is clear this remains a research/hobby project, not production software.