statsig-wasm

📈 Wasm bindings for the Statsig JavaScript (Web) SDK.

statsig-wasm lets you drive Statsig — initialise the client, run session replay, run autocapture — straight from your Rust/Wasm frontend, instead of dropping back into a patch of hand-written JS every time. You define your user in Rust, it gets serialised across the Wasm boundary for you, and the rest is just method calls on a typed StatsigClient.

Disclaimer: this project has no affiliation with the official Statsig project or trademark.

📦 Installation
🔧 Setup
🧪 Usage
🛠️ Requirements
📁 Repo & Contributions
📄 License

⸻

📦 Installation

It's a library crate, so add it to your project with:

cargo add statsig-wasm

⸻

🔧 Setup

These bindings call into the Statsig JS client that lives on the global Statsig namespace — so that script has to be on the page before your Wasm module runs. Add the following to your HTML <head>:

<script
  src="https://cdn.jsdelivr.net/npm/@statsig/js-client@3/build/statsig-js-client+session-replay+web-analytics.min.js"
  crossorigin="anonymous"
>
</script>

That particular bundle ships session replay and web analytics (autocapture) baked in, which is what the run_statsig_session_replay and run_statsig_auto_capture bindings below reach for — so keep those in the URL if you intend to use them.

Bear in mind, if you're happy for Statsig to autoinitialise the client, just append ?apikey=<YOUR_CLIENT_API_KEY> to the script's src above and uninstall this crate 😉

If you're looking to initialise the client yourself, read on.

⸻

🧪 Usage

Initialise the client

Build a StatsigClient from your client API key and a user, then kick off initialisation:

use statsig_wasm::{run_statsig_auto_capture, StatsigClient, StatsigUser};

let statsig = StatsigClient::new(
    env!("STATSIG_API_KEY"),
    StatsigUser {
        user_id: user_id.get(),
    },
)
.unwrap();

run_statsig_auto_capture(&statsig);

// `spawn_local` is native to Leptos, use your
// framework's equivalent to run the async method.
spawn_local(async move {
    statsig.initialize().await;
});

StatsigUser is serialised to the shape Statsig expects (your user_id lands as userID), so you stay in Rust and don't hand-roll the JS object.

Initialise synchronously

If you're not in an async context — or just don't want to await — there's a synchronous initialiser that returns straight away:

statsig.initialize_sync();

Session replay & autocapture

Both are one-liners that take the client you've already built. Call them before (or right alongside) initialisation:

use statsig_wasm::{run_statsig_auto_capture, run_statsig_session_replay};

run_statsig_session_replay(&statsig);
run_statsig_auto_capture(&statsig);

Just remember they need the matching features in the JS bundle from Setup — the session-replay+web-analytics build covers both.

⸻

🛠️ Requirements

A Wasm frontend: this is a wasm-bindgen crate meant to compile to wasm32 and run in the browser — it's not a native-target library
The Statsig JS client on the page: the CDN script from Setup has to be loaded, since the bindings call into the global Statsig namespace
Rust 1.85+: the crate is on the 2024 edition, so you'll want a recent toolchain

⸻

📁 Repo & Contributions

🛠️ Repo: https://github.com/dsplce-co/statsig-wasm
📦 Crate: https://crates.io/crates/statsig-wasm

PRs welcome, feel free to contribute

⸻

📄 License

MIT or Apache-2.0, at your option.