swift-os — a real operating system, written in Swift

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Embedded Swift · aarch64 · experimental, but real A real operating system,<br>written entirely in Swift.<br>Most hobby kernels stop at “Hello from the kernel.” swift-os keeps going — a native Swift userland, an in-kernel TCP/IP stack, capability-based isolation, its own HTTP server, and a native Swift AI inference server . You can even try it in your browser.<br>Run locally Read the docs GitHub Try in your browser beta

qemu · swift-os · aarch64

Real HTTP + AI inference swift-os answers real requests.<br>A pure-Swift, in-kernel TCP/IP stack drives virtio-net. /bin/httpd serves files and /bin/llmd serves a TinyStories transformer over HTTP on :8080 — both native Embedded Swift, running unprivileged at EL0. Boot it in your browser and hit it yourself.<br>boot.log — tail<br>Copy [ ok ] swift-os kernel (Embedded Swift, signed)<br>[ ok ] MMU enabled · EL1 · 256 MiB<br>[ ok ] virtio-net up · DHCPv4 10.0.2.15/24<br>[ ok ] httpd listening on :8080<br>[ ok ] llmd ready · GET /health · POST /completion

How it serves HTTP & AI<br>Kernel<br>Embedded Swift<br>freestanding · no stdlib / Foundation

Boot to login

deterministic · signed image

Seed packages<br>lua · nginx · sqlite3 · curl …

Serving<br>httpd · llmd<br>:8080<br>static files + TinyStories

What it is Efficient, reliable minimalism — not another Unix.<br>A small trusted core, capability-based isolation, deterministic boot, and signed immutable images. swift-os removes legacy rather than emulating it.

Minimal Swift kernel<br>A freestanding Embedded Swift kernel — no Foundation, no stdlib, no GC. Value types and ~Copyable ownership at the metal.

Capability security<br>Authority is a capability you hold, not a uid you are. No ambient root==0 power; typed handles are landing now.

Native Swift userland<br>Real tools — a shell, id, ps, top, httpd, ssh — compiled as Embedded Swift, running unprivileged at EL0.

In-kernel networking<br>A pure-Swift TCP/IP stack over virtio-net: IPv4, DHCP, DNS, TCP/UDP — driving its own /bin/httpd.

AI inference, natively<br>/bin/llmd serves a TinyStories transformer over HTTP — POST /completion — written in Embedded Swift. The flagship app/AI-hosting profile, proven.

Immutable images<br>Boot a signed, read-only base.img; writes land in a tmpfs that vanishes on reboot. Reproducible by design.

Architecture A clear line between userland and kernel.<br>Swift tools run unprivileged at EL0. Every<br>privileged action crosses a single, audited syscall boundary into the kernel at EL1, which owns the MMU, scheduler, network stack, and drivers.<br>See all diagrams<br>EL0 · userland shellhttpdllmdid

syscall boundary<br>EL1 · kernel schedulerMMUTCP/IPvirtio

Honest by default We tell you exactly what works today.<br>Experimental but real means no overclaiming. The status page carries the honesty so the rest of the site can be confident.

AArch64 boot QEMU virt Swift userland TCP/IP + HTTP TinyStories llmd Capabilities · hardening Packages · 12 ports SMP · active Linux ABI · non-goal x86-64 · non-goal<br>See the full status & roadmap

Start here Pick a path.

Try it in your browser<br>Boot swift-os with zero setup — qemu-system-aarch64 in WebAssembly.<br>Run it in 5 minutes<br>clone → build → make run. Boots in QEMU on Apple Silicon.<br>Understand the design<br>Vector diagrams of boot, isolation, networking, and the security model.