# extism/extism

The framework for building with WebAssembly (wasm). Easily & securely load wasm modules, move data, call functions, and build extensible apps.

Repository: https://github.com/extism/extism
Canonical: https://ross.abutalabs.com/products/extism
Homepage: https://extism.org
Language: Rust
License: BSD-3-Clause
License Family: permissive
Topics: plugin-system, c, cpp, go, ocaml, python, ruby, rust, haskell, wasm, webassembly, node, elixir, javascript, browser, csharp, dotnet, java, zig, serverless
Last push: 2026-08-25T21:00:04+00:00

## Health v2 (maintenance only)
Score: 91/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 75, longevity 100
- inputs: {"age_days": 1481, "days_push": 8, "days_rel": 90, "gap_med": 36.5, "n_releases_24m": 13}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 5739, forks 166 (observed 2026-08-28T04:09:28.402634+00:00)

## What it is
Extism is a cross-language framework for building with WebAssembly, providing host SDKs and plugin development kits to securely load and run sandboxed Wasm modules inside applications. It lets developers add extensible plugin systems, FaaS platforms, and user-supplied code execution to software written in many languages.

## Use cases
- add a plugin system to my application
- run untrusted user code safely in a sandbox
- execute webassembly modules from python or go
- build an extensible app where users write plugins
- run wasm code on servers, edge, and browsers with one interface
- embed user-supplied logic into my cli tool

## When to choose
- you need to run arbitrary or untrusted code from users in a sandbox
- you want a cross-language plugin interface with SDKs for many host languages
- you want portable wasm execution across servers, edge, CLIs, IoT, and browsers
- you need host-controlled capabilities like HTTP, timers, and memory limits for plugins

## When to avoid
- you only need a simple in-process plugin mechanism in a single language
- you need maximum raw performance with no sandboxing overhead
- your plugins require full native access to the host system
- you want a full-featured wasm runtime API rather than an opinionated plugin framework

## Facets
- artifact type: framework
- maturity: active
- function: plugin-system, wasm, sdk, developer-tools
- domain: developer-tools, web-development, cross-platform, security
- platform: windows, cross-platform, browser, python, rust, go, cli, wasm, serverless, embedded
- tags: webassembly-runtime, host-sdks, pdk, sandboxed-execution, extensibility, faas, sandboxing, linux, macos, nodejs

## Member repositories
- extism/extism (main) score 91

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:28.402634+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:53:21.843523+00:00, confidence not recorded.
  - readme: https://github.com/extism/extism (fetched 2026-08-28T04:09:28.402634+00:00, sha c313fc6acf7e)
  - homepage: https://extism.org (fetched 2026-08-29T08:48:51.860980+00:00, sha 26c548db8046)
  - site_page: https://extism.org/docs/overview (fetched 2026-08-29T08:48:51.863297+00:00, sha c91c9d7a38d0)
  - site_page: https://extism.org/docs/category/quickstart (fetched 2026-08-29T08:48:51.864981+00:00, sha 9abfac3e06a2)
  - site_page: https://extism.org/docs/category/concepts (fetched 2026-08-29T08:48:51.866470+00:00, sha 396c2817ee05)
  - site_page: https://extism.org/docs/install (fetched 2026-08-29T08:48:51.868104+00:00, sha 2d9ab1724505)
  - site_page: https://extism.org/docs/quickstart/host-quickstart (fetched 2026-08-29T08:48:51.869911+00:00, sha c3102bf09007)
  - site_page: https://extism.org/docs/quickstart/plugin-quickstart (fetched 2026-08-29T08:48:51.872033+00:00, sha ab907d4c7607)
  - registry_crates: https://crates.io/api/v1/crates/extism (fetched 2026-08-29T08:48:51.874051+00:00, sha 9862a7b05348)
- Data as of 2026-08-30T08:39:29.467469+00:00.