diff --git a/frontend/src/helpers/__tests__/querySyncHelper.spec.js b/frontend/src/helpers/__tests__/querySyncHelper.spec.js
new file mode 100644
index 0000000000..b351725e87
--- /dev/null
+++ b/frontend/src/helpers/__tests__/querySyncHelper.spec.js
@@ -0,0 +1,73 @@
+import { getQueryAsString } from '@/helpers/querySyncHelper'
+
+describe('getQueryAsString', () => {
+  it('should return an empty string for an empty query object', () => {
+    const result = getQueryAsString({})
+    expect(result).toBe('')
+  })
+
+  it('should convert a simple query object to a query string', () => {
+    const queryObj = {
+      responsible: '3bde8a8a-4dd5-45aa-8b21-f3f9811b5ea2',
+      category: 'c829d2d0-7e81-4b6e-8f68-9b4d2c58a109',
+    }
+    const result = getQueryAsString(queryObj)
+    expect(result).toBe(
+      '?responsible=3bde8a8a-4dd5-45aa-8b21-f3f9811b5ea2&category=c829d2d0-7e81-4b6e-8f68-9b4d2c58a109'
+    )
+  })
+
+  it('should handle array values in the query object', () => {
+    const queryObj = {
+      responsible: [
+        '3bde8a8a-4dd5-45aa-8b21-f3f9811b5ea2',
+        '65cdde81-32bc-4ff3-9f59-9e23c1a6ec6a',
+      ],
+      category: 'c829d2d0-7e81-4b6e-8f68-9b4d2c58a109',
+      progressLabel: ['f4d40dd5-049b-4ae0-9a04-18c34f35b4a5'],
+    }
+    const result = getQueryAsString(queryObj)
+    expect(result).toBe(
+      '?responsible=3bde8a8a-4dd5-45aa-8b21-f3f9811b5ea2&responsible=65cdde81-32bc-4ff3-9f59-9e23c1a6ec6a&category=c829d2d0-7e81-4b6e-8f68-9b4d2c58a109&progressLabel=f4d40dd5-049b-4ae0-9a04-18c34f35b4a5'
+    )
+  })
+
+  it('should properly encode special characters in keys and values', () => {
+    const queryObj = {
+      'responsible@1': '3bde8a8a-4dd5-45aa-8b21-f3f9811b5ea2',
+      'category&2': 'c829d2d0-7e81-4b6e-8f68-9b4d2c58a109',
+      progressLabel$3: 'f4d40dd5-049b-4ae0-9a04-18c34f35b4a5',
+    }
+    const result = getQueryAsString(queryObj)
+    expect(result).toBe(
+      '?responsible%401=3bde8a8a-4dd5-45aa-8b21-f3f9811b5ea2&category%262=c829d2d0-7e81-4b6e-8f68-9b4d2c58a109&progressLabel%243=f4d40dd5-049b-4ae0-9a04-18c34f35b4a5'
+    )
+  })
+
+  it('should handle a mix of string and array values', () => {
+    const queryObj = {
+      responsible: [
+        '3bde8a8a-4dd5-45aa-8b21-f3f9811b5ea2',
+        '65cdde81-32bc-4ff3-9f59-9e23c1a6ec6a',
+      ],
+      category: 'c829d2d0-7e81-4b6e-8f68-9b4d2c58a109',
+      progressLabel: ['f4d40dd5-049b-4ae0-9a04-18c34f35b4a5'],
+    }
+    const result = getQueryAsString(queryObj)
+    expect(result).toBe(
+      '?responsible=3bde8a8a-4dd5-45aa-8b21-f3f9811b5ea2&responsible=65cdde81-32bc-4ff3-9f59-9e23c1a6ec6a&category=c829d2d0-7e81-4b6e-8f68-9b4d2c58a109&progressLabel=f4d40dd5-049b-4ae0-9a04-18c34f35b4a5'
+    )
+  })
+
+  it('should ignore key-value pairs with null values', () => {
+    const queryObj = {
+      responsible: '3bde8a8a-4dd5-45aa-8b21-f3f9811b5ea2',
+      category: null,
+      progressLabel: 'f4d40dd5-049b-4ae0-9a04-18c34f35b4a5',
+    }
+    const result = getQueryAsString(queryObj)
+    expect(result).toBe(
+      '?responsible=3bde8a8a-4dd5-45aa-8b21-f3f9811b5ea2&progressLabel=f4d40dd5-049b-4ae0-9a04-18c34f35b4a5'
+    )
+  })
+})
diff --git a/frontend/src/helpers/querySyncHelper.js b/frontend/src/helpers/querySyncHelper.js
index 8a12a80090..dc641c91cc 100644
--- a/frontend/src/helpers/querySyncHelper.js
+++ b/frontend/src/helpers/querySyncHelper.js
@@ -1,20 +1,25 @@
 /**
- *
- * @param queryObj{{[p: string]: string[] | string}}
- * @return {string}
+ * Converts a query object to a query string.
+ * @param {Record<string, string|string[]|null|undefined>} queryObj - The query object.
+ * @returns {string} The query string.
  */
 export function getQueryAsString(queryObj) {
-  const params = Object.entries(queryObj).map(([key, vals]) => {
-    if (typeof vals === 'string') {
-      return `&${key}=${vals}`
-    } else {
-      let q = ''
-      for (const val of vals) {
-        q = `${q}&${key}=${val}`
-      }
-      return q
-    }
-  })
-  if (params.length === 0) return ''
-  return '?' + params.join('').slice(1)
+  const queryParams = []
+
+  for (const [key, values] of Object.entries(queryObj)) {
+    if (values === null || values === undefined) continue
+    const normalizedValues = Array.isArray(values) ? values : [values]
+
+    const paramStrings = normalizedValues.map(
+      (value) => `${encodeURIComponent(key)}=${encodeURIComponent(value)}`
+    )
+
+    queryParams.push(...paramStrings)
+  }
+
+  if (queryParams.length === 0) {
+    return ''
+  }
+
+  return '?' + queryParams.join('&')
 }