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Wasmi - WebAssembly (Wasm) Interpreter

Wasmi is an efficient and lightweight WebAssembly interpreter with a focus on constrained and embedded systems.

Distinct Features

• Simple, correct and deterministic execution of WebAssembly.
• Efficient and cross-platform WebAssembly runtime for no_std embedded environments.
• Compiler/JIT bomb resisting translation.
• Loosely mirrors the Wasmtime API to act as drop-in replacement.
• 100% WebAssembly spec testsuite compliance.
• Built-in support for fuel metering.
• Supports the official Wasm C-API.

Security Audits

Wasmi is suitable for safety critical use cases and has been audited twice.

Wasmi Version(s)	Auditor	Contractor	Report
0.36.0-0.38.0	Runtime Verification Inc.	Stellar Development Foundation	PDF
0.31.0	SRLabs	Parity Technologies	PDF

Docs

• 📖 Usage Guide: learn how to use the Wasmi API properly.
• 🛠️ Development Guide: learn how to develop for Wasmi.
• ✨ Crate Features: learn about wasmi crate features.

WebAssembly Features

	WebAssembly Proposal				WebAssembly Proposal
✅	mutable-global	≥ 0.14.0		✅	custom-page-sizes	≥ 0.41.0
✅	saturating-float-to-int	≥ 0.14.0		✅	memory64	≥ 0.41.0
✅	sign-extension	≥ 0.14.0		✅	wide-arithmetic	≥ 0.42.0
✅	multi-value	≥ 0.14.0		✅	simd	≥ 0.43.0
✅	bulk-memory	≥ 0.24.0		✅	relaxed-simd	≥ 0.44.0
✅	reference-types	≥ 0.24.0		📅	function-references	Tracking Issue
✅	tail-calls	≥ 0.28.0		📅	gc	Tracking Issue
✅	extended-const	≥ 0.29.0		📅	threads	Tracking Issue
✅	multi-memory	≥ 0.37.0		📅	exception-handling	Tracking Issue

	Embeddings
✅	WASI	WASI (wasip1) support via the wasmi_wasi crate.
✅	C-API	Official Wasm C-API support via the wasmi_c_api_impl crate.

Used by

If you want your project on this list please inform me about you project and how Wasmi is used.

Soroban · Typst · Zellij · Josh · Ripple · Firefly Zero · icu4x · orbitinghail · smoldot · Munal OS · Ayaka · Project Oak

Sponsors

Special thanks to the past and present sponsors of the Wasmi project.

Sponsoring since Oct. 2024

Sponsored until Oct. 2024

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.