diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..41afe05
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+check-mirrors-summary.md
diff --git a/check-mirrors.sh b/check-mirrors.sh
index 3ad7c1b..b0c74cf 100755
--- a/check-mirrors.sh
+++ b/check-mirrors.sh
@@ -1,22 +1,41 @@
 #!/bin/sh
 
+summary_path="${GITHUB_STEP_SUMMARY:-check-mirrors-summary.md}"
 temp_path="$(mktemp)"
 
 zig_version="$(curl -sSL 'https://ziglang.org/download/index.json' | jq -r '.master.version')"
-filename="zig-linux-x86_64-$zig_version.tar.xz"
+filename="zig-x86_64-linux-$zig_version.tar.xz"
 
 curl -L "https://ziglang.org/builds/$filename" >"$temp_path"
 correct_sum="$(sha512sum "$temp_path")"
 
+rm "$summary_path"
+
+echo "| URL | Owner | Result | Time (s) |" >>"$summary_path"
+echo "|:----|:------|:-------|---------:|" >>"$summary_path"
+
 jq '.[] | .[0] + " " + .[1]' -r <mirrors.json | while read -r mirror_url mirror_name; do
-	curl -L "$mirror_url/$filename" >"$temp_path"
+	time_secs="$(curl -w "%{time_total}" -L "$mirror_url/$filename" -o "$temp_path")"
 	download_status="$?"
-	mirror_sum="$(sha512sum "$temp_path")"
 
 	if [ "$download_status" -eq 0 ]; then
+		mirror_sum="$(sha512sum "$temp_path")"
 		if [ "$mirror_sum" = "$correct_sum" ]; then
-			continue
+			err="" # success
+		else
+			err="checksum mismatch: $mirror_sum (expected $correct_sum)"
 		fi
+	else
+		err="curl exit status: $download_status"
+	fi
+
+	md_time_secs="$(printf '`%0.2f`' "$time_secs")" # 2dp, backticks
+	md_mirror_name="$(echo "$mirror_name" | sed -e 's/[<>]/\\\0/g')" # backslash-prefix angle brackets
+	md_status="$(if [ "$err" = "" ]; then echo ":white_check_mark:"; else echo ":warning: \`$err\`"; fi)" # tick or cross for success
+	echo "| $mirror_url | $md_mirror_name | $md_status | $md_time_secs |" >>"$summary_path"
+
+	if [ "$err" = "" ]; then
+		continue # success
 	fi
 
 	curl -s \