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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.

                   

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.