diff --git a/packages/node/download_core.js b/packages/node/download_core.js
index a68738d86..f1bc28c77 100644
--- a/packages/node/download_core.js
+++ b/packages/node/download_core.js
@@ -1,4 +1,5 @@
 // TODO: Make this a pre-publish hook and just bundle everything
+import { createHash } from 'node:crypto';
 import * as OS from 'node:os';
 import * as fs from 'node:fs/promises';
 import * as path from 'node:path';
@@ -6,7 +7,15 @@ import { Readable } from 'node:stream';
 import { finished } from 'node:stream/promises';
 import { exit } from 'node:process';
 
+// When changing this version, run node download_core.js update_hashes
 const version = '0.3.14';
+const versionHashes = {
+  'powersync_x64.dll': 'ba0fda2496878d195ea5530562509cc585fa4702fd308594d0eef6f37060dafe',
+  'libpowersync_x64.so': '4cee8675b78af786f26f1e1666367de3d228f584084cca257e879060302c1371',
+  'libpowersync_aarch64.so': 'ed4ec55cb29ac4b295dc076de71e4247b08d46db562a53e2875cc47420a97a55',
+  'libpowersync_x64.dylib': 'cec6fb04732dd8c9a8ec6c6028b1b996965a0a359b0461d7dd6aa885d6eccddf',
+  'libpowersync_aarch64.dylib': '55b60e156c3ddc9e7d6fae273943b94b83481c861676c9bcd1e2cfcea02b0a18'
+};
 
 const platform = OS.platform();
 let destination;
@@ -23,24 +32,68 @@ if (platform === 'win32') {
   destination = 'libpowersync.dylib';
 }
 
+const expectedHash = versionHashes[asset];
 const destinationPath = path.resolve('lib', destination);
-try {
-  await fs.access(destinationPath);
-  exit(0);
-} catch {}
-
-const url = `https://github.com/powersync-ja/powersync-sqlite-core/releases/download/v${version}/${asset}`;
-const response = await fetch(url);
-if (response.status != 200) {
-  throw `Could not download ${url}`;
-}
 
-try {
-  await fs.access('lib');
-} catch {
-  await fs.mkdir('lib');
-}
+const hashStream = async (input) => {
+  for await (const chunk of input.pipe(createHash('sha256')).setEncoding('hex')) {
+    return chunk;
+  }
+};
+
+const hashLocal = async () => {
+  try {
+    const handle = await fs.open(destinationPath, 'r');
+    const input = handle.createReadStream();
+
+    const result = await hashStream(input);
+    await handle.close();
+    return result;
+  } catch {
+    return null;
+  }
+};
+
+const download = async () => {
+  if ((await hashLocal()) == expectedHash) {
+    console.debug('Local copy is up-to-date, skipping download');
+    exit(0);
+  }
+
+  const url = `https://github.com/powersync-ja/powersync-sqlite-core/releases/download/v${version}/${asset}`;
+  const response = await fetch(url);
+  if (response.status != 200) {
+    throw `Could not download ${url}`;
+  }
 
-const file = await fs.open(destinationPath, 'w');
-await finished(Readable.fromWeb(response.body).pipe(file.createWriteStream()));
-await file.close();
+  try {
+    await fs.access('lib');
+  } catch {
+    await fs.mkdir('lib');
+  }
+
+  const file = await fs.open(destinationPath, 'w');
+  await finished(Readable.fromWeb(response.body).pipe(file.createWriteStream()));
+  await file.close();
+
+  const hashAfterDownloading = await hashLocal();
+  if (hashAfterDownloading != expectedHash) {
+    throw `Unexpected hash after downloading (got ${hashAfterDownloading}, expected ${expectedHash})`;
+  }
+};
+
+const updateReferenceHashes = async () => {
+  for (const asset of Object.keys(versionHashes)) {
+    const url = `https://github.com/powersync-ja/powersync-sqlite-core/releases/download/v${version}/${asset}`;
+    const response = await fetch(url);
+    const hash = await hashStream(Readable.fromWeb(response.body));
+
+    console.log(`  '${asset}': '${hash}',`);
+  }
+};
+
+if (process.argv[process.argv.length - 1] == 'update_hashes') {
+  await updateReferenceHashes();
+} else {
+  await download();
+}