diff --git a/questionsservice/questiongeneratorservice/questiongenerator-service.js b/questionsservice/questiongeneratorservice/questiongenerator-service.js
index 1985174a..21c8721d 100644
--- a/questionsservice/questiongeneratorservice/questiongenerator-service.js
+++ b/questionsservice/questiongeneratorservice/questiongenerator-service.js
@@ -25,31 +25,44 @@ app.use(cors());
 // Only parse query parameters into strings, not objects (adds security)
 app.set('query parser', 'simple');
 
-// Function to generate the required number of questions
-async function getQuestions(req) {
-  const preguntas = req.query.n_preguntas || 1;
-  const respuestas = req.query.n_respuestas || 4;
-  var temas = req.query.tema || [];
+function validateNumberInQuery(number, minValue, paramName, defValue) {
+  if (!(paramName in number)) return defValue;
+  n = Number(number[paramName]);
+  if (isNaN(n)) throw new Error(`A number was expected in param \'${paramName}\'`);
+  if (n < minValue) throw new Error(`\'${paramName}\' must be at least \'${minValue}\'`);
+  return n;
+}
+
+// Function to validate required fields in the request body
+function validateFields(query) {
+  const preguntas = validateNumberInQuery(query, 1, 'n_preguntas', 1);
+  const respuestas = validateNumberInQuery(query, 1, 'n_respuestas', 4);
+  var temas = query.tema || [];
   if (!Array.isArray(temas)) {
     temas = Array.of(temas);
-  } 
-
-  return await QuestionGenerator.generateQuestions(preguntas, respuestas, temas);
+  }
+  return { preguntas, respuestas, temas };
 }
 
 // Route for getting questions
 app.get('/questions', async (req, res) => {
   try {
-    const retQuestions = await getQuestions(req);
-    try{
-      const questionsHistoryResponse = await axios.post(questionHistoryServiceUrl + '/history/questions', retQuestions);
+    const { preguntas, respuestas, temas } = validateFields(req.query);
+    try {
+      const retQuestions = await QuestionGenerator.generateQuestions(preguntas, respuestas, temas);
+      try {
+        await axios.post(questionHistoryServiceUrl + '/history/questions', retQuestions);
+      } catch (error) {
+        console.error(`Error saving questions history: ${error}`);
+      }
+      res.json(retQuestions);
     } catch (error) {
-      console.error(`Error saving questions history: ${error}`);
+      console.error(`An error occurred: ${error.message}`);
+      res.status(500).json({ error: 'Internal Server Error' });
     }
-    res.json(retQuestions);
   } catch (error) {
-    console.error(`An error occurred: ${error.message}`)
-    res.status(500).json({ error: 'Internal Server Error' });
+    console.error(`Bad Request: ${error.message}`);
+    res.status(400).json({ message: error.message });
   }
 });
 
diff --git a/questionsservice/questiongeneratorservice/questiongenerator.js b/questionsservice/questiongeneratorservice/questiongenerator.js
index 1b180ccc..89206f31 100644
--- a/questionsservice/questiongeneratorservice/questiongenerator.js
+++ b/questionsservice/questiongeneratorservice/questiongenerator.js
@@ -36,8 +36,13 @@ class QuestionGenerator {
 
         const randomDocs = await Pais.aggregate([
             { $match: plantilla.filtro },
-            { $sample: { size: Number(respuestas) } }
+            { $sample: { size: respuestas } }
         ]);
+        if (randomDocs.length < respuestas) {
+            console.error(`Not enought data found to generate a question`);
+            throw new Error(`Not enought data found to generate a question`);
+        }
+
         console.log("\nFind:");
         console.log(randomDocs);
 
@@ -75,7 +80,15 @@ class QuestionGenerator {
                 templates = templates.concat(this.temas.get(tema));
                 console.log(this.temas.get(tema));
             }
+            else {
+                console.error(`The topic \'${tema}\' is not currently defined`);
+                throw new Error(`The topic \'${tema}\' is not currently defined`);
+            }
         });
+        if (templates.length == 0) {
+            console.error(`No correct topics were passed`);
+            throw new Error(`No correct topics were passed`);
+        }
         console.log(templates);
         console.log([...new Set(templates)]);
         return [...new Set(templates)];