diff --git a/src/api.js b/src/api.js
index 1ddeac9..56b1950 100644
--- a/src/api.js
+++ b/src/api.js
@@ -21,7 +21,7 @@ const s3 = new S3Client({
   },
 });
 
-/** Helpers **/
+/* ---------------- helpers ---------------- */
 
 const toListed = (folderKey) => (o) => {
   const d = o.LastModified ?? new Date(0);
@@ -49,34 +49,40 @@ const byNewest = (a, b) => b.sort - a.sort;
 const sidecarsFor = (key) => [key + ".sha256", key + ".sig"];
 
 const parseName = (fname) => {
-  // Expected pattern: parts[3] = platform (windows|darwin|linux), parts[4] = arch
+  // Expected convention: parts[3] = platform (windows|darwin|linux), parts[4] = arch
   const parts = fname.split("_");
-  const platform = parts[3] ?? "";
+  const platform = (parts[3] ?? "").toLowerCase();
   const arch = parts[4] ?? "";
   const groupId = `${parts[0] ?? ""}_${platform}_${arch}`;
   return { parts, platform, arch, groupId };
 };
 
-const windowsCompanionFromTar = (tarKey) => {
-  // .../name.tar.gz -> .../name_setup.exe
-  const base = tarKey.slice(0, -TAR_EXT.length);
-  return `${base}_setup.exe`;
+// Remove sidecar suffixes first, then packaging suffix to compute a common base across variants
+const stripSidecar = (name) => {
+  if (name.endsWith(".sha256")) return name.slice(0, -".sha256".length);
+  if (name.endsWith(".sig")) return name.slice(0, -".sig".length);
+  return name;
 };
 
-const darwinCompanionFromTar = (tarKey) => {
-  // .../name.tar.gz -> .../name.dmg
-  const base = tarKey.slice(0, -TAR_EXT.length);
-  return `${base}.dmg`;
+const stripPackaging = (name) => {
+  if (name.endsWith(TAR_EXT)) return name.slice(0, -TAR_EXT.length); // correct length
+  if (name.endsWith("_setup.exe")) return name.slice(0, -"_setup.exe".length);
+  if (name.endsWith(".dmg")) return name.slice(0, -".dmg".length);
+  return name;
 };
 
-/** Public API **/
+const baseStem = (name) => stripPackaging(stripSidecar(name));
+
+const isTar = (name) => name.endsWith(TAR_EXT);
+const isDmg = (name) => name.endsWith(".dmg");
+const isSetup = (name) => name.endsWith("_setup.exe");
+
+/* ---------------- public API ---------------- */
 
 const cleanOldItems = async () => {
   const keys = Array.from(oldKeys);
   console.log(`cleaning|count|${keys.length}`);
-  if (keys.length === 0) {
-    return;
-  }
+  if (keys.length === 0) return;
 
   const deletes = keys.map((Key) =>
     s3
@@ -84,7 +90,6 @@ const cleanOldItems = async () => {
       .then(() => console.log(`cleaning|key|${Key}`))
       .catch((err) => console.error(`cleaning|error|${Key}`, err)),
   );
-
   await Promise.allSettled(deletes);
   oldKeys.clear();
 };
@@ -115,86 +120,117 @@ const getBucketFiles = async (folderName) => {
     );
 
     const contents = (data.Contents ?? []).filter((it) => it.Key !== folderKey);
-
-    // Normalize listing
     const listed = contents.map(toListed(folderKey)).sort(byNewest);
 
-    // Consider only .tar.gz for retention policy
-    const tarItems = listed.filter((i) => i.name.endsWith(TAR_EXT));
-
-    // Nightly policy: keep top 3 per (name_platform_arch); mark others + companions for deletion
-    const keepSet = new Set();
-    if (folder === "nightly") {
-      const groupCounts = {};
-      for (const t of tarItems) {
-        const { groupId, platform } = parseName(t.name);
-        groupCounts[groupId] = (groupCounts[groupId] ?? 0) + 1;
-        const count = groupCounts[groupId];
-
-        if (count <= 3) {
-          keepSet.add(t.key);
-        } else {
-          [t.key, ...sidecarsFor(t.key)].forEach((k) => oldKeys.add(k));
-
-          if (platform === "windows") {
-            const setupKey = windowsCompanionFromTar(t.key);
-            [setupKey, ...sidecarsFor(setupKey)].forEach((k) => oldKeys.add(k));
-          } else if (platform === "darwin") {
-            const dmgKey = darwinCompanionFromTar(t.key);
-            [dmgKey, ...sidecarsFor(dmgKey)].forEach((k) => oldKeys.add(k));
-          }
-        }
+    // Build indexes
+    const byKey = Object.fromEntries(listed.map((i) => [i.key, i]));
+    const byBase = new Map(); // base -> { tar, dmg, setup, sidecars:Set<string> }
+    for (const it of listed) {
+      const base = baseStem(it.name);
+      let g = byBase.get(base);
+      if (!g) {
+        g = { tar: null, dmg: null, setup: null, sidecars: new Set() };
+        byBase.set(base, g);
+      }
+      if (isTar(it.name)) {
+        g.tar = it;
+      } else if (isDmg(it.name)) {
+        g.dmg = it;
+      } else if (isSetup(it.name)) {
+        g.setup = it;
+      } else if (it.name.endsWith(".sha256") || it.name.endsWith(".sig")) {
+        g.sidecars.add(it.key);
       }
-    } else {
-      tarItems.forEach((t) => keepSet.add(t.key));
     }
 
-    // Build final output list (tar + sidecars + optional platform companion + its sidecars)
-    const byKey = Object.fromEntries(listed.map((i) => [i.key, i]));
+    const groups = Array.from(byBase.values());
+
+    // Nightly retention: keep newest 3 per (name_platform_arch).
+    const keepBaseSet = new Set();
+    if (folder === "nightly") {
+      const buckets = new Map(); // groupId -> array of group objects
+      for (const g of groups) {
+        const rep = g.tar ?? g.dmg ?? g.setup;
+        if (!rep) continue;
+        const { groupId } = parseName(rep.name);
+        if (!buckets.has(groupId)) buckets.set(groupId, []);
+        buckets.get(groupId).push(g);
+      }
+
+      for (const [, arr] of buckets) {
+        arr.sort((a, b) => {
+          const ta = (a.tar ?? a.dmg ?? a.setup)?.sort ?? 0;
+          const tb = (b.tar ?? b.dmg ?? b.setup)?.sort ?? 0;
+          return tb - ta;
+        });
+
+        arr.forEach((g, idx) => {
+          const rep = g.tar ?? g.dmg ?? g.setup;
+          if (!rep) return;
+          const base = baseStem(rep.name);
+          if (idx < 3) {
+            keepBaseSet.add(base);
+          } else {
+            // mark all artifacts in the group as old
+            if (g.tar)
+              [g.tar.key, ...sidecarsFor(g.tar.key)].forEach((k) =>
+                oldKeys.add(k),
+              );
+            if (g.dmg)
+              [g.dmg.key, ...sidecarsFor(g.dmg.key)].forEach((k) =>
+                oldKeys.add(k),
+              );
+            if (g.setup)
+              [g.setup.key, ...sidecarsFor(g.setup.key)].forEach((k) =>
+                oldKeys.add(k),
+              );
+          }
+        });
+      }
+    } else {
+      // keep all groups in non-nightly
+      for (const g of groups) {
+        const rep = g.tar ?? g.dmg ?? g.setup;
+        if (rep) keepBaseSet.add(baseStem(rep.name));
+      }
+    }
+
+    // Emit kept groups in newest-first order, using representative timestamp
+    const kept = groups
+      .filter((g) => {
+        const rep = g.tar ?? g.dmg ?? g.setup;
+        return rep && keepBaseSet.has(baseStem(rep.name));
+      })
+      .sort((a, b) => {
+        const ta = (a.tar ?? a.dmg ?? a.setup)?.sort ?? 0;
+        const tb = (b.tar ?? b.dmg ?? b.setup)?.sort ?? 0;
+        return tb - ta;
+      });
+
     const out = [];
-
-    for (const t of tarItems) {
-      if (!keepSet.has(t.key)) {
-        continue;
-      }
-
-      // tar.gz
-      out.push(t);
-
-      // tar sidecars
-      for (const sk of sidecarsFor(t.key)) {
-        const it = byKey[sk];
-        if (it) {
-          out.push(it);
+    for (const g of kept) {
+      // tar + sidecars
+      if (g.tar) {
+        out.push(g.tar);
+        for (const sk of sidecarsFor(g.tar.key)) {
+          const it = byKey[sk];
+          if (it) out.push(it);
         }
       }
-
-      // platform companions
-      const { platform } = parseName(t.name);
-
-      if (platform === "windows") {
-        const setupKey = windowsCompanionFromTar(t.key);
-        const setupItem = byKey[setupKey];
-        if (setupItem) {
-          out.push(setupItem);
-          for (const sk of sidecarsFor(setupKey)) {
-            const it = byKey[sk];
-            if (it) {
-              out.push(it);
-            }
-          }
+      // dmg + sidecars
+      if (g.dmg) {
+        out.push(g.dmg);
+        for (const sk of sidecarsFor(g.dmg.key)) {
+          const it = byKey[sk];
+          if (it) out.push(it);
         }
-      } else if (platform === "darwin") {
-        const dmgKey = darwinCompanionFromTar(t.key);
-        const dmgItem = byKey[dmgKey];
-        if (dmgItem) {
-          out.push(dmgItem);
-          for (const sk of sidecarsFor(dmgKey)) {
-            const it = byKey[sk];
-            if (it) {
-              out.push(it);
-            }
-          }
+      }
+      // setup + sidecars
+      if (g.setup) {
+        out.push(g.setup);
+        for (const sk of sidecarsFor(g.setup.key)) {
+          const it = byKey[sk];
+          if (it) out.push(it);
         }
       }
     }