diff --git a/backend/api/routes.py b/backend/api/routes.py
index f52258d..e84950b 100644
--- a/backend/api/routes.py
+++ b/backend/api/routes.py
@@ -1,8 +1,54 @@
 from fastapi import FastAPI
+from pydantic import BaseModel
+from typing import List, Dict
 
 app = FastAPI()
 
+class ValueFunctionRequest(BaseModel):
+    criterion_name: str
+    levels: List[str]
+    blank_cards: List[int]
+    references: Dict[str, float]
+
 @app.get("/prueba")
-def ruta_de_prueba():
-    # En FastAPI si devuelves un diccionario, se transforma a JSON
-    return {"mensaje": "¡Hola desde FastAPI! El contenedor de docker está funcionando"}
\ No newline at end of file
+def prueba():
+    return {"mensaje": "¡Hola desde FastAPI! El contenedor de docker está funcionando"}
+
+@app.post("/api/criteria/doc/value-function")
+def calcular(request: ValueFunctionRequest):
+    levels = request.levels
+    cards_between_levels = request.blank_cards
+    reference_values = request.references
+
+    # Índices de referencia (por ejemplo 0 y 4)
+    ref_indices = sorted(int(k) for k in reference_values)
+    lower_ref, upper_ref = ref_indices
+
+    # Valores asignados a esas referencias
+    lower_value = reference_values[str(lower_ref)]
+    upper_value = reference_values[str(upper_ref)]
+
+    # Total de unidades entre las referencias
+    total_units = sum(cards_between_levels[i] + 1 for i in range(lower_ref, upper_ref))
+
+    # Valor por unidad
+    unit_value = (upper_value - lower_value) / total_units if total_units else 0
+
+    # Lista de valores finales
+    values = [0] * len(levels)
+    values[lower_ref] = lower_value
+
+    # Hacia arriba
+    for i in range(lower_ref + 1, len(levels)):
+        units = sum(cards_between_levels[r] + 1 for r in range(lower_ref, i))
+        values[i] = lower_value + unit_value * units
+
+    # Hacia abajo
+    for i in range(lower_ref - 1, -1, -1):
+        units = sum(cards_between_levels[r] + 1 for r in range(i, lower_ref))
+        values[i] = lower_value - unit_value * units
+
+    return {
+        "criterion_name": request.criterion_name,
+        "values": {levels[i]: round(values[i], 4) for i in range(len(levels))}
+    }