diff --git a/.github/workflows/check-mirrors.yaml b/.github/workflows/check-mirrors.yaml
new file mode 100644
index 0000000..a76e4c4
--- /dev/null
+++ b/.github/workflows/check-mirrors.yaml
@@ -0,0 +1,25 @@
+{
+  "name": "check-mirrors",
+  "on": {
+    "schedule": [
+      { "cron": "0 6,18 * * *" },
+    ],
+    "workflow_dispatch": null,
+  },
+  "jobs": {
+    "check-mirrors": {
+      "runs-on": "ubuntu-latest",
+      "steps": [
+        { "uses": "actions/checkout@v4" },
+        {
+          "name": "Check mirrors",
+          "env": {
+            "PUSHOVER_USER": "${{ secrets.PUSHOVER_USER }}",
+            "PUSHOVER_TOKEN": "${{ secrets.PUSHOVER_TOKEN }}",
+          },
+          "run": "sh check-mirrors.sh",
+        },
+      ],
+    },
+  },
+}
diff --git a/check-mirrors.sh b/check-mirrors.sh
new file mode 100755
index 0000000..3ad7c1b
--- /dev/null
+++ b/check-mirrors.sh
@@ -0,0 +1,28 @@
+#!/bin/sh
+
+temp_path="$(mktemp)"
+
+zig_version="$(curl -sSL 'https://ziglang.org/download/index.json' | jq -r '.master.version')"
+filename="zig-linux-x86_64-$zig_version.tar.xz"
+
+curl -L "https://ziglang.org/builds/$filename" >"$temp_path"
+correct_sum="$(sha512sum "$temp_path")"
+
+jq '.[] | .[0] + " " + .[1]' -r <mirrors.json | while read -r mirror_url mirror_name; do
+	curl -L "$mirror_url/$filename" >"$temp_path"
+	download_status="$?"
+	mirror_sum="$(sha512sum "$temp_path")"
+
+	if [ "$download_status" -eq 0 ]; then
+		if [ "$mirror_sum" = "$correct_sum" ]; then
+			continue
+		fi
+	fi
+
+	curl -s \
+		-F user="$PUSHOVER_USER" -F token="$PUSHOVER_TOKEN" \
+		-F message="Zig download mirror '$mirror_name' is down" \
+		https://api.pushover.net/1/messages.json
+done
+
+rm "$temp_path"
diff --git a/main.js b/main.js
index 0af8fa7..48bc891 100644
--- a/main.js
+++ b/main.js
@@ -15,11 +15,8 @@ const CANONICAL = 'https://ziglang.org/builds';
 
 // The list of mirrors we attempt to fetch from. These need not be trusted, as
 // we always verify the minisign signature.
-const MIRRORS = [
-  'https://pkg.machengine.org/zig', // slimsag <stephen@hexops.com>
-  'https://zigmirror.hryx.net/zig', // hryx <codroid@gmail.com>
-  'https://zig.linus.dev/zig',      // linusg <mail@linusgroh.de>
-];
+// This is an array of URLs.
+const MIRRORS = require('./mirrors.json').map((x) => x[0]);
 
 async function downloadFromMirror(mirror, tarball_name, tarball_ext) {
   const tarball_path = await tc.downloadTool(`${mirror}/${tarball_name}${tarball_ext}?source=github-actions`);
diff --git a/mirrors.json b/mirrors.json
new file mode 100644
index 0000000..bee01a7
--- /dev/null
+++ b/mirrors.json
@@ -0,0 +1,5 @@
+[
+	[ "https://pkg.machengine.org/zig", "slimsag <stephen@hexops.com>" ],
+	[ "https://zigmirror.hryx.net/zig", "hryx <codroid@gmail.com>"     ],
+	[ "https://zig.linus.dev/zig",      "linusg <mail@linusgroh.de>"   ]
+]