diff --git a/.npmignore b/.npmignore
index 452190b..1ed313f 100644
--- a/.npmignore
+++ b/.npmignore
@@ -7,4 +7,4 @@ docs
 .github
 CODE_OF_CONDUCT.md
 SECURITY.md
-CONTRIBUTING.md
\ No newline at end of file
+CONTRIBUTING.md
diff --git a/README.md b/README.md
index c2480a3..b4038d8 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,26 @@ $ npm install @performanc/voice
 $ npm install github:PerformanC/voice
 ```
 
+### Native build requirements
+
+Installation builds the native audio sender and requires Python, a C compiler,
+and the libsodium development files.
+
+On Windows, use the official Visual Studio libsodium package and set
+`SODIUM_ROOT` to its extracted directory:
+
+```powershell
+$env:SODIUM_ROOT = 'C:\path\to\libsodium'
+npm install
+```
+
+The build also detects a static libsodium installation under `VCPKG_ROOT`.
+Custom layouts can set `SODIUM_INCLUDE_DIR` to the directory containing
+`sodium.h` and `SODIUM_LIB` to the full path of the static `.lib` file.
+
+Linux and macOS builds use the system libsodium development package, such as
+`libsodium-dev` on Debian/Ubuntu or `brew install libsodium` on macOS.
+
 ## Usage
 
 ```javascript
diff --git a/index.js b/index.js
index d5b996a..9404c8c 100644
--- a/index.js
+++ b/index.js
@@ -1150,7 +1150,7 @@ class Connection extends EventEmitter {
           nonce.fill(0)
           data.copy(nonce, 0, data.length - 4, data.length)
 
-          const headerSize = 12 + cc * 4
+          let headerSize = 12 + cc * 4
           let extensionLengthInWords = 0
           if (data.length < headerSize) return;
 
diff --git a/native/binding.gyp b/native/binding.gyp
index 6a15511..f263f95 100644
--- a/native/binding.gyp
+++ b/native/binding.gyp
@@ -4,15 +4,12 @@
       "target_name": "voice_send_native",
       "sources": [
         "src/binding.c",
+        "src/cthreads.c",
         "src/voice_send.c"
       ],
       "include_dirs": [
         "."
       ],
-      "libraries": [
-        "-lsodium",
-        "-lpthread"
-      ],
       "conditions": [
         ["OS=='linux'", {
           "cflags": [
@@ -21,9 +18,16 @@
             "-Wextra",
             "-Wpedantic"
           ],
-          "ldflags": []
+          "libraries": [
+            "-lsodium",
+            "-lpthread"
+          ]
         }],
         ["OS=='mac'", {
+          "libraries": [
+            "-lsodium",
+            "-lpthread"
+          ],
           "xcode_settings": {
             "OTHER_CFLAGS": [
               "-std=c99",
@@ -34,11 +38,37 @@
           }
         }],
         ["OS=='win'", {
+          "defines": [
+            "SODIUM_STATIC"
+          ],
+          "msvs_settings": {
+            "VCCLCompilerTool": {
+              "AdditionalOptions!": [
+                "-flto=full",
+                "-flto=thin"
+              ]
+            },
+            "VCLibrarianTool": {
+              "AdditionalOptions!": [
+                "-flto=full",
+                "-flto=thin"
+              ]
+            },
+            "VCLinkerTool": {
+              "AdditionalOptions!": [
+                "-flto=full",
+                "-flto=thin",
+                "/opt:lldltojobs=<(lto_jobs)"
+              ]
+            }
+          },
           "libraries": [
-            "-lsodium.lib"
+            "<!(node find-libsodium.js library <(target_arch))",
+            "ws2_32.lib"
           ],
           "include_dirs": [
-            "src"
+            "src",
+            "<!(node find-libsodium.js include <(target_arch))"
           ]
         }]
       ]
diff --git a/native/find-libsodium.js b/native/find-libsodium.js
new file mode 100644
index 0000000..d0294fb
--- /dev/null
+++ b/native/find-libsodium.js
@@ -0,0 +1,105 @@
+import fs from 'node:fs'
+import path from 'node:path'
+
+const [kind, targetArch] = process.argv.slice(2)
+const archNames = {
+  arm64: 'ARM64',
+  ia32: 'Win32',
+  x64: 'x64'
+}
+const vcpkgArchNames = {
+  arm64: 'arm64',
+  ia32: 'x86',
+  x64: 'x64'
+}
+
+if (!['include', 'library'].includes(kind) || !archNames[targetArch]) {
+  fail(`Unsupported libsodium lookup: ${kind ?? ''} ${targetArch ?? ''}`)
+}
+
+const roots = []
+const sodiumRoot = process.env.SODIUM_ROOT ?? process.env.npm_config_sodium_root
+
+if (sodiumRoot) {
+  roots.push(sodiumRoot)
+  roots.push(vcpkgInstalledRoot(sodiumRoot))
+}
+
+if (process.env.VCPKG_ROOT) {
+  roots.push(vcpkgInstalledRoot(process.env.VCPKG_ROOT))
+}
+
+const candidates =
+  kind === 'include'
+    ? includeCandidates(roots)
+    : libraryCandidates(roots, targetArch)
+const result = candidates.find(
+  (candidate) => candidate && fs.existsSync(candidate)
+)
+
+if (!result) {
+  fail(
+    `Could not find the libsodium ${kind}. Set SODIUM_ROOT to a libsodium ` +
+      'SDK directory, or set SODIUM_INCLUDE_DIR and SODIUM_LIB explicitly. ' +
+      'A VCPKG_ROOT installation is also supported.'
+  )
+}
+
+process.stdout.write(
+  path.resolve(kind === 'include' ? path.dirname(result) : result)
+)
+
+function includeCandidates(searchRoots) {
+  return [
+    process.env.SODIUM_INCLUDE_DIR,
+    ...searchRoots.map((root) => root && path.join(root, 'include'))
+  ]
+    .filter(Boolean)
+    .map((includeDir) => path.join(includeDir, 'sodium.h'))
+}
+
+function libraryCandidates(searchRoots, arch) {
+  const candidates = [process.env.SODIUM_LIB]
+
+  for (const root of searchRoots.filter(Boolean)) {
+    candidates.push(
+      path.join(root, 'lib', 'libsodium.lib'),
+      path.join(root, 'lib', 'sodium.lib')
+    )
+
+    const releaseRoot = path.join(root, archNames[arch], 'Release')
+    if (!fs.existsSync(releaseRoot)) continue
+
+    const toolsets = fs
+      .readdirSync(releaseRoot, { withFileTypes: true })
+      .filter((entry) => entry.isDirectory() && /^v\d+$/.test(entry.name))
+      .map((entry) => entry.name)
+      .sort((left, right) =>
+        right.localeCompare(left, undefined, {
+          numeric: true
+        })
+      )
+
+    for (const toolset of toolsets) {
+      candidates.push(
+        path.join(releaseRoot, toolset, 'static', 'libsodium.lib')
+      )
+    }
+  }
+
+  return candidates.filter(Boolean)
+}
+
+function vcpkgInstalledRoot(root) {
+  const triplet =
+    process.env.VCPKG_TARGET_TRIPLET ??
+    process.env.VCPKG_DEFAULT_TRIPLET ??
+    `${vcpkgArchNames[targetArch]}-windows-static`
+
+  return path.join(root, 'installed', triplet)
+}
+
+function fail(message) {
+  process.stderr.write(`\n@performanc/voice: ${message}\n`)
+  process.exit(1)
+}
diff --git a/native/src/binding.c b/native/src/binding.c
index fb41568..26d478d 100644
--- a/native/src/binding.c
+++ b/native/src/binding.c
@@ -113,7 +113,7 @@ static void *loop_thread_func(void *arg) {
     /* INFO: Send via UDP */
     if (pkt_len > 0) {
       int sent = os_sendto(nc->udp_fd, packet, (size_t)pkt_len, 0, (const struct sockaddr *)&nc->udp_addr, sizeof(nc->udp_addr));
-      if (sent == (ssize_t)pkt_len) {
+      if (sent == pkt_len) {
         nc->ctx.stats.packets_sent++;
 
         /* INFO: Update the stats counter and sync to JS every 50 packets */