diff --git a/main.go b/main.go
index e62b5f2..444102a 100644
--- a/main.go
+++ b/main.go
@@ -519,13 +519,15 @@ func (s *Server) indexJob(id, root string) {
 	s.jobsMu.Unlock()
 	snapshot.ID = uniqueID("snapshot")
 
-	// Only the latest snapshot is kept; older workspaces are deleted.
+	// Each session keeps only its latest snapshot; its older workspaces are deleted.
 	s.snapshotsMu.Lock()
 	var oldRoots []string
-	for _, old := range s.snapshots {
-		oldRoots = append(oldRoots, old.Root)
+	for key, old := range s.snapshots {
+		if old.Owner == snapshot.Owner {
+			oldRoots = append(oldRoots, old.Root)
+			delete(s.snapshots, key)
+		}
 	}
-	clear(s.snapshots)
 	s.snapshots[snapshot.ID] = snapshot
 	s.snapshotsMu.Unlock()
 	for _, old := range oldRoots {
diff --git a/main_test.go b/main_test.go
index e283a5b..795dc59 100644
--- a/main_test.go
+++ b/main_test.go
@@ -286,3 +286,40 @@ func TestSessionCookieFlags(t *testing.T) {
 		}
 	}
 }
+
+// indexLocal uploads files as a local job and waits for the snapshot.
+func (c client) indexLocal(files map[string]string) (jobID, snapshotID string) {
+	c.t.Helper()
+	var created struct{ JobID string }
+	c.json("POST", "/api/jobs", `{"kind":"local"}`, 201, &created)
+	for path, content := range files {
+		c.json("POST", "/api/jobs/"+created.JobID+"/files?path="+path, content, 200, nil)
+	}
+	c.json("POST", "/api/jobs/"+created.JobID+"/commit", "", 202, nil)
+	status, raw := c.do("GET", "/api/jobs/"+created.JobID+"/events", "")
+	var job Job
+	for line := range strings.Lines(string(raw)) {
+		if data, ok := strings.CutPrefix(line, "data: "); ok {
+			json.Unmarshal([]byte(data), &job)
+		}
+	}
+	if status != 200 || job.SnapshotID == nil {
+		c.t.Fatalf("job did not finish: %d %+v", status, job)
+	}
+	return created.JobID, *job.SnapshotID
+}
+
+func TestSessionsKeepIndependentSnapshots(t *testing.T) {
+	server, alice := newTestServer(t)
+	bob := alice.stranger()
+	_, aliceFirst := alice.indexLocal(map[string]string{"a.go": "package a"})
+	_, bobSnapshot := bob.indexLocal(map[string]string{"b.go": "package b"})
+	_, aliceSecond := alice.indexLocal(map[string]string{"c.go": "package c"})
+
+	alice.json("GET", "/api/snapshots/"+aliceFirst, "", 404, nil)
+	alice.json("GET", "/api/snapshots/"+aliceSecond, "", 200, nil)
+	bob.json("GET", "/api/snapshots/"+bobSnapshot, "", 200, nil)
+	if len(server.snapshots) != 2 {
+		t.Fatalf("snapshots = %d, want 2", len(server.snapshots))
+	}
+}