Building the Package Registry in Wyn

December 2025

The package registry at pkg.wynlang.com is written in Wyn. This was partly practical — we needed a registry — and partly a test of whether the language is ready for real server work.

The setup

The server is about 130 lines. Each incoming request gets its own spawned task. SQLite stores package metadata. Tarballs go on the filesystem.

fn main() -> int {
    var db = Db.open("/opt/pkg/registry.db")
    var server = Http.listen(3001)
    while true {
        var req = Http.accept(server)
        if req != "" {
            spawn handle_request(req, db)
        }
    }
    return 0
}

No framework, no middleware stack, no dependency injection. Just a loop that accepts connections and spawns handlers.

What worked well

The standard library covered everything we needed. HTTP server, SQLite, JSON parsing, file I/O, crypto for API keys. We didn't install a single package to build the registry.

spawn per request turned out to be the right default. No thread pool sizing, no async/await ceremony. The M:N scheduler handles the rest.

Single binary deployment is the best feature nobody talks about. The registry is a 300KB binary. Deploy means scp and systemctl restart. No Docker, no container orchestration, no dependency resolution on the target machine.

What was rough

Error messages from the type checker were sometimes confusing when working with nested function calls. We've since improved these — the compiler now shows both the expected and actual types with a suggestion for how to fix it.

String interpolation didn't work in all contexts (match arms, struct field initializers). This is still a known limitation we're working on.

The numbers

• Server binary: ~300KB
• Memory at idle: ~2MB
• Lines of Wyn: 130 (server) + 80 (API handlers)
• Deploy time: ~5 seconds
• Uptime since launch: no crashes

The registry handles package search, publish, and install. It's not going to win any scalability awards, but for a language ecosystem with dozens of packages, it's more than enough.