A universal modular Library OS (libOS) for zkVM-powered verifiable applications.

ZeroOS is a modular library operating system that transforms normal applications into verifiable applications (vApps) simply by linking against a lightweight, platform-agnostic OS layer. Unlike prior zkVM stacks that rely on patched toolchains and modified language runtimes, ZeroOS requires no changes to libc or language standard libraries. Developers use off-the-shelf Rust/C toolchains, link against ZeroOS, and obtain a deterministic, zkVM-compatible unikernel.

ZeroOS enables zkVMs to standardize around a shared OS layer—radically reducing fragmentation, audit burden, and maintenance cost across the ecosystem. Every zkVM platform integrating ZeroOS implements only one function: __platform_bootstrap.

ZeroOS is open-source, built for extensibility, and designed to encourage community contributions.

ZeroOS intercepts real syscall instructions and implements a stable subset of the Linux syscall ABI inside the kernel.

• Works with unmodified musl libc and Rust std
• Eliminates version hell associated with patched toolchains
• Ensures long-term ABI stability (kernel ABIs are more stable than language runtimes)

ZeroOS is composed of small, swappable kernel modules:

• Memory allocators (freelist, buddy, bump, etc.)
• Syscall wrappers toggled via compile-time flags
• Swappable schedulers
• Optional I/O and device modules

Developers include only what their vApp requires—minimizing trusted computing base and zkVM trace length.

Every subsystem is engineered to preserve determinism:

• No external nondeterminism (time, randomness, signals are stubbed or controlled)
• Single-address-space unikernel model
• All guest behavior is fully captured by the zkVM trace

To port ZeroOS to a zkVM, implement only:

void __platform_bootstrap();

This function sets up:

• Trap handler registration
• Memory-mapped I/O regions
• Platform-specific device initialization

Everything else is shared across all platforms.

ZeroOS builds a fully static ELF that runs directly on the zkVM’s bare-metal execution model while preserving the familiar POSIX/Linux syscall interface.

./bootstrap

If you're working in a devcontainer, run:

./bootstrap --install-shell-integration

./build-fibonacci.sh
./build-std-smoke.sh
./build-c-smoke.sh

cargo matrix fix
cargo matrix fmt
cargo matrix check
cargo matrix test

or

cargo massage

See LICENSE-MIT and LICENSE-APACHE for details.