diff --git a/main.py b/main.py
index fda39aa..81755b9 100644
--- a/main.py
+++ b/main.py
@@ -21,7 +21,7 @@ def clamp_limit(limit: int) -> int:
 
 import off
 from db import Base, engine, get_db
-from models import Food, Recipe, TelemetryDaily
+from models import Food, Recipe, TelemetryDaily, TelemetryActive
 
 
 # Columnas añadidas a `recipes` después de la v1 (id/name/servings/items). En
@@ -278,6 +278,7 @@ def delete_cookbook(author_id: str, db: Session = Depends(get_db)):
 class TelemetryIn(BaseModel):
     day: str
     app_version: str | None = None
+    install_id: str | None = None
     active_modules: list[str] = []
     opens_by_module: dict[str, int] = {}
     seconds_by_module: dict[str, int] = {}
@@ -337,6 +338,12 @@ def add_telemetry(body: TelemetryIn, db: Session = Depends(get_db)):
         row.active = (row.active or 0) + delta["active"]
         row.opens = (row.opens or 0) + delta["opens"]
         row.seconds = (row.seconds or 0) + delta["seconds"]
+
+    # Presencia (instalación, día) para contar instalaciones únicas.
+    install_id = (body.install_id or "").strip()[:64]
+    if install_id and db.get(TelemetryActive, (install_id, day)) is None:
+        db.add(TelemetryActive(install_id=install_id, day=day))
+
     db.commit()
     return {"ok": True}
 
@@ -372,7 +379,26 @@ def telemetry_summary(days: int = 30, db: Session = Depends(get_db)):
             "seconds": int(seconds or 0),
         })
     modules.sort(key=lambda x: x["opens"], reverse=True)
-    return {"sinceDays": days, "submissions": submissions, "modules": modules}
+
+    # Instalaciones únicas (por install_id): total, activas en el periodo y hoy.
+    today = date.today().isoformat()
+    installs_total = db.query(
+        func.count(func.distinct(TelemetryActive.install_id))).scalar() or 0
+    installs_active = db.query(
+        func.count(func.distinct(TelemetryActive.install_id))
+    ).filter(TelemetryActive.day >= cutoff).scalar() or 0
+    dau_today = db.query(
+        func.count(func.distinct(TelemetryActive.install_id))
+    ).filter(TelemetryActive.day == today).scalar() or 0
+
+    return {
+        "sinceDays": days,
+        "submissions": submissions,
+        "installsTotal": int(installs_total),
+        "installsActive": int(installs_active),
+        "dauToday": int(dau_today),
+        "modules": modules,
+    }
 
 
 @app.post("/recipes")
diff --git a/models.py b/models.py
index 86638e8..764a133 100644
--- a/models.py
+++ b/models.py
@@ -85,3 +85,13 @@ class TelemetryDaily(Base):
     active = Column(Integer, default=0)
     opens = Column(Integer, default=0)
     seconds = Column(Integer, default=0)       # tiempo en pantalla acumulado
+
+
+class TelemetryActive(Base):
+    """Presencia (instalación, día) para contar instalaciones ÚNICAS, DAU/MAU y
+    retención. El install_id es un identificador anónimo de la instalación (un
+    número aleatorio, sin nada personal)."""
+    __tablename__ = "telemetry_active"
+
+    install_id = Column(String, primary_key=True)
+    day = Column(String, primary_key=True)  # 'YYYY-MM-DD'
diff --git a/test_telemetry.py b/test_telemetry.py
index 9769a05..76f8ea3 100644
--- a/test_telemetry.py
+++ b/test_telemetry.py
@@ -23,6 +23,7 @@ def test_telemetria_agrega_y_resume():
     r1 = client.post("/telemetry", json={
         "day": day,
         "app_version": "2.27.0",
+        "install_id": "inst-A",
         "active_modules": ["fasting", "weight", "alcohol"],
         "opens_by_module": {"alcohol": 3, "weight": 1},
         "seconds_by_module": {"alcohol": 120, "aprende:sueno": 45},
@@ -30,14 +31,22 @@ def test_telemetria_agrega_y_resume():
     assert r1.status_code < 300, r1.text
     r2 = client.post("/telemetry", json={
         "day": day,
+        "install_id": "inst-B",
         "active_modules": ["fasting", "alcohol"],
         "opens_by_module": {"alcohol": 2},
         "seconds_by_module": {"alcohol": 60},
     })
     assert r2.status_code < 300, r2.text
+    # Tercer envío de una instalación ya vista (inst-A): no suma instalación única.
+    r3 = client.post("/telemetry", json={"day": day, "install_id": "inst-A"})
+    assert r3.status_code < 300, r3.text
 
     summary = client.get("/telemetry/summary").json()
-    assert summary["submissions"] == 2  # dos envíos ese día
+    assert summary["submissions"] == 3  # tres envíos ese día
+    # Dos instalaciones únicas (inst-A duplicada no cuenta doble), ambas hoy.
+    assert summary["installsTotal"] == 2
+    assert summary["installsActive"] == 2
+    assert summary["dauToday"] == 2
     by_module = {m["module"]: m for m in summary["modules"]}
     # alcohol: activo en 2 envíos, abierto 3+2 = 5 veces, 120+60 = 180 s.
     assert by_module["alcohol"]["activeInstallDays"] == 2
@@ -49,7 +58,8 @@ def test_telemetria_agrega_y_resume():
     # Versión de la app (fragmentación): el primer envío fue 2.27.0, el segundo
     # sin versión → 'unknown'.
     assert by_module["ver:2.27.0"]["activeInstallDays"] == 1
-    assert by_module["ver:unknown"]["activeInstallDays"] == 1
+    # r2 y r3 sin app_version → ver:unknown cuenta 2.
+    assert by_module["ver:unknown"]["activeInstallDays"] == 2
     # fasting: activo en 2 envíos, 0 aperturas.
     assert by_module["fasting"]["activeInstallDays"] == 2
     assert by_module["fasting"]["opens"] == 0