GoKawiilCruller: a production-focused Bun runtime ported to Zig 0.16
Cruller is a fork of the last Zig-based Bun release, reduced to the parts needed to run already-built production JavaScript servers and ported to vanilla Zig 0.16.
Repository: GitHub - solenopsys/cruller: fork of Bun · GitHub
The project keeps JavaScriptCore, Bun.serve , HTTP/1-3, WebSockets, fetch , streams, Blob , Request / Response , static serving, and the module resolver for pre-built JavaScript. It removes the package manager, bundler/transpiler, shell, test runner, most CLI dispatch, N-API, SQL clients, archive support, and other development-oriented subsystems.
The interesting part of the port was separating the runtime from Bun’s old patched Zig build integration. Cruller now has a vanilla Zig 0.16 build graph, compatibility shims for APIs changed since Zig 0.15, and a generated-code embedding module so release builds remain portable instead of loading generated JS from the build directory at runtime.
The main design decision is to treat this as a runtime, not a general-purpose Bun replacement. A minimal launcher loads a pre-built entrypoint; features that require package installation, bundling, TypeScript transformation, or bun test are intentionally outside the scope.
Current measurements on Linux x64, compared with the official Bun 1.3.14 binary:
Cruller ReleaseFast stripped runtime: 73.0 MiB
stripped runtime: 73.0 MiB Official Bun runtime: 88.5 MiB
Size reduction: about 18%
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