diff --git a/src/components/Alert/AlertBox.tsx b/src/components/Alert/AlertBox.tsx
new file mode 100644
index 00000000..fa617aff
--- /dev/null
+++ b/src/components/Alert/AlertBox.tsx
@@ -0,0 +1,35 @@
+import {Stack} from '@mui/material'
+import {FC} from 'react'
+import {useContainer} from 'unstated-next'
+
+import {AlertContainer} from '@/utils/AlertContainer'
+
+import {Button} from '../Clickable/Button'
+import {Dialog} from '../Dialog/Dialog'
+
+export const AlertBox: FC = () => {
+  const container = useContainer(AlertContainer)
+
+  const closeContainer = () => {
+    container.setAlertBox({
+      message: container.alertBox?.message ?? '',
+      title: container.alertBox?.title ?? '',
+      isOpen: false,
+    })
+  }
+
+  return (
+    <Dialog
+      open={container.alertBox?.isOpen ?? false}
+      title={container.alertBox?.title}
+      contentText={container.alertBox?.message}
+      close={closeContainer}
+    >
+      <Stack direction={'row'} mt={3} justifyContent="center">
+        <Button variant="button1" onClick={closeContainer}>
+          Dobre
+        </Button>
+      </Stack>
+    </Dialog>
+  )
+}
diff --git a/src/components/PageLayout/LoginForm/LoginForm.tsx b/src/components/PageLayout/LoginForm/LoginForm.tsx
index 50973b7d..41366b72 100644
--- a/src/components/PageLayout/LoginForm/LoginForm.tsx
+++ b/src/components/PageLayout/LoginForm/LoginForm.tsx
@@ -8,6 +8,7 @@ import {Link} from '@/components/Clickable/Link'
 import {Dialog} from '@/components/Dialog/Dialog'
 import {FormInput} from '@/components/FormItems/FormInput/FormInput'
 import {AuthContainer} from '@/utils/AuthContainer'
+import {useAlert} from '@/utils/useAlert'
 import {useSeminarInfo} from '@/utils/useSeminarInfo'
 
 import {PasswordResetRequestForm} from '../PasswordResetRequest/PasswordResetRequest'
@@ -30,6 +31,7 @@ export const LoginForm: FC<LoginFormProps> = ({closeDialog}) => {
   const {login} = AuthContainer.useContainer()
   const {handleSubmit, control} = useForm<LoginFormValues>({defaultValues})
   const {seminar} = useSeminarInfo()
+  const {alert} = useAlert()
 
   const router = useRouter()
 
diff --git a/src/components/Problems/UploadProblemForm.tsx b/src/components/Problems/UploadProblemForm.tsx
index 120e0abf..ea9fc343 100644
--- a/src/components/Problems/UploadProblemForm.tsx
+++ b/src/components/Problems/UploadProblemForm.tsx
@@ -6,6 +6,7 @@ import {useDropzone} from 'react-dropzone'
 
 import {CloseButton} from '@/components/CloseButton/CloseButton'
 import {niceBytes} from '@/utils/niceBytes'
+import {useAlert} from '@/utils/useAlert'
 
 import {Button} from '../Clickable/Button'
 import {Link} from '../Clickable/Link'
@@ -28,6 +29,8 @@ export const UploadProblemForm: FC<{
   isAfterDeadline,
   invalidateSeriesQuery,
 }) => {
+  const {alert} = useAlert()
+
   const {mutate: uploadSolution} = useMutation({
     mutationFn: (formData: FormData) => axios.post(`/api/competition/problem/${problemId}/upload-solution`, formData),
     onSuccess: (response) => {
diff --git a/src/components/Profile/PasswordChangeForm.tsx b/src/components/Profile/PasswordChangeForm.tsx
index c7a2e910..f1994485 100644
--- a/src/components/Profile/PasswordChangeForm.tsx
+++ b/src/components/Profile/PasswordChangeForm.tsx
@@ -5,6 +5,7 @@ import {FC} from 'react'
 import {SubmitHandler, useForm} from 'react-hook-form'
 
 import {IGeneralPostResponse} from '@/types/api/general'
+import {useAlert} from '@/utils/useAlert'
 
 import {Button} from '../Clickable/Button'
 import {Dialog} from '../Dialog/Dialog'
@@ -33,6 +34,7 @@ interface ChangePasswordErrorResponseData {
 
 export const PasswordChangeDialog: FC<PasswordChangeDialogProps> = ({open, close}) => {
   const {handleSubmit, reset, control, getValues, setError} = useForm<PasswordChangeDialogValues>({defaultValues})
+  const {alert} = useAlert()
 
   const onSuccess = () => {
     alert('Zmena hesla prebehla úspešne.')
diff --git a/src/components/RegisterForm/RegisterForm.tsx b/src/components/RegisterForm/RegisterForm.tsx
index 0c04e537..8a9faedb 100644
--- a/src/components/RegisterForm/RegisterForm.tsx
+++ b/src/components/RegisterForm/RegisterForm.tsx
@@ -7,6 +7,7 @@ import {SubmitHandler, useForm, useFormState} from 'react-hook-form'
 
 import {FormInput} from '@/components/FormItems/FormInput/FormInput'
 import {IGeneralPostResponse} from '@/types/api/general'
+import {useAlert} from '@/utils/useAlert'
 import {useSeminarInfo} from '@/utils/useSeminarInfo'
 
 import {useNavigationTrap} from '../../utils/useNavigationTrap'
@@ -62,6 +63,7 @@ export const RegisterForm: FC = () => {
   const router = useRouter()
 
   const {seminar} = useSeminarInfo()
+  const {alert} = useAlert()
 
   const transformFormData = (data: RegisterFormValues) => ({
     email: data.email,
diff --git a/src/pages/_app.tsx b/src/pages/_app.tsx
index 3896747f..2f94de6e 100644
--- a/src/pages/_app.tsx
+++ b/src/pages/_app.tsx
@@ -6,11 +6,14 @@ import {isAxiosError} from 'axios'
 import {AppProps} from 'next/app'
 import dynamic from 'next/dynamic'
 import Head from 'next/head'
-import {FC} from 'react'
+import {FC, PropsWithChildren, useMemo} from 'react'
 import {CookiesProvider} from 'react-cookie'
 
+import {AlertBox} from '@/components/Alert/AlertBox'
 import {theme} from '@/theme'
+import {AlertContainer} from '@/utils/AlertContainer'
 import {AuthContainer} from '@/utils/AuthContainer'
+import {useAlert} from '@/utils/useAlert'
 
 const ReactQueryDevtools = dynamic(
   () => import('@tanstack/react-query-devtools').then(({ReactQueryDevtools}) => ReactQueryDevtools),
@@ -71,6 +74,68 @@ const queryClient = new QueryClient({
   },
 })
 
+const ReactQueryProvider: FC<PropsWithChildren> = ({children}) => {
+  const {alert} = useAlert()
+
+  const queryClient = useMemo(
+    () =>
+      new QueryClient({
+        defaultOptions: {
+          queries: {
+            retry: (failureCount, error) => {
+              if (isAxiosError(error)) {
+                // nechceme retryovat 403 (Forbidden)
+                const status = error.response?.status
+                if (status === 403 || status === 404) return false
+              }
+              // klasika - retryuj len 3x
+              if (failureCount >= 3) return false
+              return true
+            },
+          },
+          mutations: {
+            // globalny error handler requestov cez useMutation
+            // notes:
+            // - useMutation vzdy sam loguje error do konzoly, my nemusime
+            // - specifikovanim `onError` na nejakej `useMutation` sa tento handler prepise, tak sa tomu vyhybajme
+            onError: (error) => {
+              if (isAxiosError(error)) {
+                const data = error.response?.data as unknown
+                if (typeof data === 'object' && data) {
+                  // ak mame vlastny message v `.detail`, ukazeme userovi ten
+                  const detail = 'detail' in data && data.detail
+                  if (typeof detail === 'string') {
+                    alert(detail)
+                    return
+                  }
+
+                  // ak nie, ale mame message v `.non_field_errors`, ukazeme ten
+                  const nonFieldErrors = 'non_field_errors' in data && data.non_field_errors
+                  const nonFieldError = Array.isArray(nonFieldErrors) && (nonFieldErrors as unknown[])[0]
+                  if (typeof nonFieldError === 'string') {
+                    alert(nonFieldError)
+                    return
+                  }
+
+                  // TODO: handle field errors (napr. na password) - nealertovat usera, ale zobrazit v UI? alebo alert s prvym field errorom
+
+                  // ak nie, ukazeme kludne original anglicku hlasku z `error`u
+                  alert(error.message)
+                  return
+                }
+              } else {
+                alert(error.message)
+              }
+            },
+          },
+        },
+      }),
+    [alert],
+  )
+
+  return <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
+}
+
 const MyApp: FC<AppProps> = ({Component, pageProps}) => {
   return (
     <>
@@ -86,16 +151,19 @@ const MyApp: FC<AppProps> = ({Component, pageProps}) => {
           font-family: ${theme.typography.fontFamily};
         }
       `}</style>
-      <QueryClientProvider client={queryClient}>
-        <ReactQueryDevtools />
-        <CookiesProvider>
-          <AuthContainer.Provider>
-            <ThemeProvider theme={theme}>
-              <Component {...pageProps} />
-            </ThemeProvider>
-          </AuthContainer.Provider>
-        </CookiesProvider>
-      </QueryClientProvider>
+      <AlertContainer.Provider>
+        <ReactQueryProvider>
+          <ReactQueryDevtools />
+          <CookiesProvider>
+            <AuthContainer.Provider>
+              <ThemeProvider theme={theme}>
+                <AlertBox />
+                <Component {...pageProps} />
+              </ThemeProvider>
+            </AuthContainer.Provider>
+          </CookiesProvider>
+        </ReactQueryProvider>
+      </AlertContainer.Provider>
     </>
   )
 }
diff --git a/src/utils/AlertContainer.tsx b/src/utils/AlertContainer.tsx
new file mode 100644
index 00000000..be86fd59
--- /dev/null
+++ b/src/utils/AlertContainer.tsx
@@ -0,0 +1,15 @@
+import {useState} from 'react'
+import {createContainer} from 'unstated-next'
+
+export interface AlertProps {
+  isOpen: boolean
+  title?: string
+  message?: string
+}
+
+const useAlertBox = () => {
+  const [alertBox, setAlertBox] = useState<AlertProps>()
+  return {alertBox, setAlertBox}
+}
+
+export const AlertContainer = createContainer(useAlertBox)
diff --git a/src/utils/useAlert.ts b/src/utils/useAlert.ts
new file mode 100644
index 00000000..ffa9fa12
--- /dev/null
+++ b/src/utils/useAlert.ts
@@ -0,0 +1,13 @@
+import {useContainer} from 'unstated-next'
+
+import {AlertContainer} from '@/utils/AlertContainer'
+
+export const useAlert = () => {
+  const container = useContainer(AlertContainer)
+
+  const alert = (message: string, title?: string) => {
+    container.setAlertBox({message: message, title: title ?? 'Upozornenie', isOpen: true})
+  }
+
+  return {alert}
+}