diff --git a/internal/httpapi/handlers_projects.go b/internal/httpapi/handlers_projects.go
index fbcef63..1d46a0e 100644
--- a/internal/httpapi/handlers_projects.go
+++ b/internal/httpapi/handlers_projects.go
@@ -212,6 +212,9 @@ func (s *Server) handleCreateProject(w http.ResponseWriter, r *http.Request) {
 	}
 	s.db.Create(&p)
 	s.audit(r, "create", "project", p.ID, p.Name)
+	if p.PMEmail != "" && !s.owns(r, p.PMEmail) {
+		s.notify(p.PMEmail, "project", "프로젝트 PM으로 지정되었습니다", p.Name, "/projects/"+p.ID)
+	}
 	writeJSON(w, http.StatusCreated, p)
 }
 
@@ -224,6 +227,7 @@ func (s *Server) handlePatchProject(w http.ResponseWriter, r *http.Request) {
 		writeError(w, http.StatusNotFound, "프로젝트를 찾을 수 없습니다")
 		return
 	}
+	oldPM := p.PMEmail
 	var patch map[string]interface{}
 	if err := decodeJSON(r, &patch); err != nil {
 		writeError(w, http.StatusBadRequest, err.Error())
@@ -238,6 +242,9 @@ func (s *Server) handlePatchProject(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	s.db.First(&p, "id = ?", p.ID)
+	if p.PMEmail != "" && !strings.EqualFold(p.PMEmail, oldPM) && !s.owns(r, p.PMEmail) {
+		s.notify(p.PMEmail, "project", "프로젝트 PM으로 지정되었습니다", p.Name, "/projects/"+p.ID)
+	}
 	writeJSON(w, http.StatusOK, p)
 }
 
@@ -383,9 +390,21 @@ func (s *Server) handleCreateTask(w http.ResponseWriter, r *http.Request) {
 		t.Lane = "todo"
 	}
 	s.db.Create(&t)
+	// 담당자로 배정되면 본인에게 알림(+모바일 푸시). 본인이 본인에게 단 경우는 제외.
+	if t.Assignee != "" && !s.owns(r, t.Assignee) {
+		s.notify(t.Assignee, "task", "작업에 배정되었습니다",
+			fmt.Sprintf("[%s] %s", s.projectName(id), t.Title), "/projects/"+id)
+	}
 	writeJSON(w, http.StatusCreated, t)
 }
 
+// projectName returns a project's name (best-effort) for notification text.
+func (s *Server) projectName(id string) string {
+	var p models.Project
+	s.db.Select("name").First(&p, "id = ?", id)
+	return p.Name
+}
+
 func (s *Server) handlePatchTask(w http.ResponseWriter, r *http.Request) {
 	var t models.ProjectTask
 	if err := s.db.First(&t, "id = ?", chi.URLParam(r, "tId")).Error; err != nil {
@@ -396,6 +415,7 @@ func (s *Server) handlePatchTask(w http.ResponseWriter, r *http.Request) {
 		writeError(w, http.StatusForbidden, "권한이 없습니다")
 		return
 	}
+	oldAssignee := t.Assignee
 	var patch map[string]interface{}
 	if err := decodeJSON(r, &patch); err != nil {
 		writeError(w, http.StatusBadRequest, err.Error())
@@ -414,6 +434,11 @@ func (s *Server) handlePatchTask(w http.ResponseWriter, r *http.Request) {
 	patch = snakeKeys(patch)
 	s.db.Model(&t).Updates(patch)
 	s.db.First(&t, "id = ?", t.ID)
+	// 담당자가 새 사람으로 바뀌면 그 사람에게 알림(+푸시).
+	if t.Assignee != "" && !strings.EqualFold(t.Assignee, oldAssignee) && !s.owns(r, t.Assignee) {
+		s.notify(t.Assignee, "task", "작업에 배정되었습니다",
+			fmt.Sprintf("[%s] %s", s.projectName(t.ProjectID), t.Title), "/projects/"+t.ProjectID)
+	}
 	writeJSON(w, http.StatusOK, t)
 }
 
@@ -459,6 +484,18 @@ func (s *Server) handleCreateTaskComment(w http.ResponseWriter, r *http.Request)
 	c.TaskID = tid
 	c.AuthorEmail = s.email(r)
 	s.db.Create(&c)
+	// 댓글이 달리면 작업 담당자에게 알림(본인 댓글 제외).
+	var t models.ProjectTask
+	if s.db.Select("assignee", "title", "project_id").First(&t, "id = ?", tid).Error == nil {
+		if t.Assignee != "" && !s.owns(r, t.Assignee) {
+			body := c.Body
+			if len(body) > 50 {
+				body = body[:50] + "…"
+			}
+			s.notify(t.Assignee, "task", "내 작업에 새 댓글",
+				fmt.Sprintf("%s — %s", t.Title, body), "/projects/"+t.ProjectID)
+		}
+	}
 	writeJSON(w, http.StatusCreated, c)
 }