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.
- 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.
- CPython
>=3.12parity target for supported Molt semantics. - Full product target: full CPython
>=3.12parity 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.
- 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.
For the full setup and troubleshooting path, use docs/getting-started.md.
uv sync --group dev --python 3.12 # installs the `molt` command into .venv
molt run examples/hello.py # build + run, like `python examples/hello.py`uv sync puts the molt command on your path (in .venv). From there the
common commands are:
molt run app.py # build and run (fast `dev` profile, like `cargo run`)
molt build app.py --release # produce an optimized standalone binary
./app # run the compiled binary directly
molt compare app.py # diff Molt's output against CPython
molt rundefaults to the fastdevprofile andmolt builddefaults to the optimizedreleaseprofile — the same convention ascargo run/cargo build --release. Override either with--profile dev|release(or the--releaseshorthand); both verbs accept both profiles. See docs/getting-started.md.
From a source checkout without activating the venv, prefix any command with
uv run --python 3.12, e.g.uv run --python 3.12 molt run examples/hello.py. The module formpython3 -m molt.cli ...is equivalent and is what the contributor proof lanes use.
- Package and installer paths: see docs/getting-started.md
- Packaging details: packaging/README.md
- Verification command:
molt doctor --json
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
- Contributor map: docs/DEVELOPER_GUIDE.md
- Operations and multi-agent workflow: docs/OPERATIONS.md
- Benchmark workflows: docs/BENCHMARKING.md