Molt

Molt compiles Python into standalone native binaries and WASM with a Rust-owned runtime, deterministic tooling, and explicit compatibility boundaries.

It is not trying to be a hidden CPython launcher. Molt targets a verified, production-minded subset that can keep expanding without giving up control over performance, packaging, or runtime semantics.

Why Molt

• Standalone output: compiled binaries do not rely on a host Python installation.
• Rust-first runtime: hot semantics and stdlib behavior are pushed down into runtime primitives and intrinsics instead of Python fallbacks.
• Deterministic engineering: parity, performance, and security are treated as measurable gates, not vague goals.
• Cross-target ambition: native and WASM are both first-class targets.

Project Contract

• CPython >=3.12 parity target for supported Molt semantics.
• Full product target: full CPython >=3.12 parity for the supported subset without hidden host fallback.
• Compiled artifacts must work without a host Python installation.
• By design, Molt does not support unrestricted exec/eval/compile, runtime monkeypatching, or unrestricted reflection in compiled binaries.

What Molt Supports Today

• Native AOT compilation through the Rust backend.
• Standalone binary workflows with no runtime dependency on local CPython.
• A growing Rust-first stdlib lowering program with generated audit surfaces.
• Differential testing against CPython as a core validation path.
• WASM build workflows, with cross-target parity still incomplete and actively tracked.

5-Minute Quickstart

For the full setup and troubleshooting path, use docs/getting-started.md.

export PYTHONPATH=src
uv run --python 3.12 python3 -m molt.cli build examples/hello.py
./hello_molt

You can also compare behavior directly against CPython:

export PYTHONPATH=src
uv run --python 3.12 python3 -m molt.cli compare examples/hello.py

Install

• Package and installer paths: see docs/getting-started.md
• Packaging details: packaging/README.md
• Verification command: molt doctor --json

Status

Current detailed state lives in docs/spec/STATUS.md. Forward priorities live in ROADMAP.md. The near-term execution slice lives in docs/ROADMAP_90_DAYS.md.

For compatibility and proof detail:

• Docs index: docs/INDEX.md
• Spec index: docs/spec/README.md
• Compatibility architecture: docs/spec/areas/compat/README.md
• Detailed benchmark report: docs/benchmarks/bench_summary.md
• Standalone proof workflow: docs/proofs/STANDALONE_BINARY_PROOF_WORKFLOW.md

Development

• Contributor map: docs/DEVELOPER_GUIDE.md
• Operations and multi-agent workflow: docs/OPERATIONS.md
• Benchmark workflows: docs/BENCHMARKING.md