diff --git a/.npmignore b/.npmignore
index c7459bd..b182fcb 100644
--- a/.npmignore
+++ b/.npmignore
@@ -1,9 +1,5 @@
-src/
 tests/
 target/
-Cargo.lock
-Cargo.toml
-build.rs
 *.node
 *.tgz
 tsconfig.json
diff --git a/package.json b/package.json
index 106867d..f5baba8 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,6 @@
     },
     "license": "Apache-2.0",
     "devDependencies": {
-        "@napi-rs/cli": "^2.18.0",
         "jest": "^28.1.0",
         "prettier": "^2.8.3",
         "typedoc": "^0.22.17",
@@ -24,13 +23,14 @@
     },
     "scripts": {
         "lint": "prettier --check .",
-        "release-build": "napi build --platform --release --strip",
+        "release-build": "napi build --platform --release --strip --cargo-flags=--locked",
         "build": "napi build --platform",
-        "postinstall": "node download-lib.js",
+        "postinstall": "node postinstall.js",
         "test": "jest --verbose --testTimeout 10000",
         "doc": "typedoc --tsconfig ."
     },
     "dependencies": {
+        "@napi-rs/cli": "^2.18.0",
         "https-proxy-agent": "^5.0.1",
         "node-downloader-helper": "^2.1.5"
     }
diff --git a/postinstall.js b/postinstall.js
new file mode 100644
index 0000000..f06926d
--- /dev/null
+++ b/postinstall.js
@@ -0,0 +1,6 @@
+if (process.env.npm_config_build_from_source) {
+	console.log('building @matrix-org/matrix-sdk-crypto-nodejs from source');
+	require('child_process').spawnSync(process.env.npm_execpath || 'npm', ['run', 'release-build']);
+} else {
+	require('./download-lib.js');
+}