diff --git a/.jules/bolt.md b/.jules/bolt.md
index 57daf471..3f822941 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -3,3 +3,6 @@
 **Learning:** `Date.parse(value)` returns the timestamp primitive directly, while `new Date(value).getTime()` also constructs a `Date` object. Both use the same ECMAScript string-parsing semantics for these call sites.
 
 **Action:** In frequently executed paths that only need a timestamp primitive, prefer `Date.parse(value)`. Treat the allocation reduction as a bounded micro-optimization unless a committed benchmark establishes a larger runtime effect.
+## 2023-10-12 - [Array Iteration Optimization in Session Export]
+**Learning:** Chained `.map(...).filter(...)` operations on large arrays allocate an intermediate array which creates GC overhead. This is problematic on hot paths like dashboard data endpoints.
+**Action:** Replace `.map().filter()` chains with a single `.reduce()` pass for array aggregations to minimize allocations and GC pause times.
diff --git a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
index 7d6a4d4a..2e304acb 100644
--- a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
+++ b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
@@ -196,9 +196,11 @@ export async function GET(
             include: sessionInclude,
           })
           const byId = new Map(rows.map((s) => [s.id, s]))
-          csvSessions = ids
-            .map((id) => byId.get(id))
-            .filter((s): s is SessionWithInclude => !!s)
+          csvSessions = ids.reduce((acc, id) => {
+            const s = byId.get(id)
+            if (s) acc.push(s)
+            return acc
+          }, [] as SessionWithInclude[])
         }
       } else {
         csvSessions = await db.claudeSession.findMany({
@@ -245,9 +247,11 @@ export async function GET(
           include: sessionInclude,
         })
         const byId = new Map(rows.map((s) => [s.id, s]))
-        sessions = ids
-          .map((id) => byId.get(id))
-          .filter((s): s is SessionWithInclude => !!s)
+        sessions = ids.reduce((acc, id) => {
+          const s = byId.get(id)
+          if (s) acc.push(s)
+          return acc
+        }, [] as SessionWithInclude[])
       }
     } else {
       const [rows, countResult] = await Promise.all([