diff --git a/package.json b/package.json
index d6ce188..6205eaf 100644
--- a/package.json
+++ b/package.json
@@ -6,6 +6,7 @@
     "@hookform/devtools": "^2.2.1",
     "@hookform/resolvers": "^1.3.7",
     "@material-ui/core": "^4.11.3",
+    "@material-ui/lab": "^4.0.0-alpha.57",
     "@testing-library/jest-dom": "^5.11.4",
     "@testing-library/react": "^11.1.0",
     "@testing-library/user-event": "^12.1.10",
@@ -15,6 +16,7 @@
     "faker": "^5.5.2",
     "http-status": "^1.5.0",
     "msw": "^0.28.0",
+    "notistack": "^1.0.5",
     "npm-run-all": "^4.1.5",
     "prettier": "^2.2.1",
     "ramda": "^0.27.1",
diff --git a/src/contexts/AppProviders.js b/src/contexts/AppProviders.js
index 8b7a9ef..1683d07 100644
--- a/src/contexts/AppProviders.js
+++ b/src/contexts/AppProviders.js
@@ -3,13 +3,16 @@ import PropTypes from 'prop-types'
 import { CssBaseline } from '@material-ui/core'
 import { QueryClientProvider } from 'contexts/QueryClientProvider'
 import { ThemeProvider } from 'contexts/ThemeContext'
+import { NotificationProvider } from 'contexts/NotificationProvider'
 
 export const AppProviders = ({ children }) => {
   return (
     <QueryClientProvider>
       <ThemeProvider>
-        <CssBaseline />
-        {children}
+        <NotificationProvider>
+          <CssBaseline />
+          {children}
+        </NotificationProvider>
       </ThemeProvider>
     </QueryClientProvider>
   )
diff --git a/src/contexts/NotificationProvider.js b/src/contexts/NotificationProvider.js
new file mode 100644
index 0000000..1f90f03
--- /dev/null
+++ b/src/contexts/NotificationProvider.js
@@ -0,0 +1,38 @@
+import { SnackbarProvider } from 'notistack'
+
+export const NotificationProvider = ({ children }) => {
+  return (
+    <SnackbarProvider
+      autoHideDuration={NOTIFICATION_TIMEOUT_MS}
+      maxSnack={NOTIFICATION_MAX_VISIBLE}
+      anchorOrigin={{
+        vertical: NOTIFICATION_POSITION_VERTICAL,
+        horizontal: NOTIFICATION_POSITION_HORIZONTAL,
+      }}>
+      {children}
+    </SnackbarProvider>
+  )
+}
+
+const NOTIFICATION_TIMEOUT_MS = 4 * 1000 // 4 seconds
+
+/**
+ * How many notifications will be visible at the same time.
+ * @constant
+ * @type {number}
+ */
+const NOTIFICATION_MAX_VISIBLE = 3
+
+/**
+ * Notifications vertical anchor origin.
+ * @constant
+ * @type {string}
+ */
+const NOTIFICATION_POSITION_VERTICAL = 'top'
+
+/**
+ * Notifications horizontal anchor origin.
+ * @constant
+ * @type {string}
+ */
+const NOTIFICATION_POSITION_HORIZONTAL = 'center'
diff --git a/src/examples/12/Form/Button.js b/src/examples/12/Form/Button.js
new file mode 100644
index 0000000..51a92e9
--- /dev/null
+++ b/src/examples/12/Form/Button.js
@@ -0,0 +1,23 @@
+import { useFormContext } from 'react-hook-form'
+import { Button as MuiButton } from '@material-ui/core'
+
+export const Button = ({
+  children = 'Submit',
+  variant = 'outlined',
+  fullWidth = true,
+  ...props
+}) => {
+  const {
+    formState: { isSubmitting },
+  } = useFormContext()
+
+  return (
+    <MuiButton
+      {...props}
+      disabled={isSubmitting}
+      variant={variant}
+      fullWidth={fullWidth}>
+      {children}
+    </MuiButton>
+  )
+}
diff --git a/src/examples/12/Form/FormProvider.js b/src/examples/12/Form/FormProvider.js
new file mode 100644
index 0000000..699e6d1
--- /dev/null
+++ b/src/examples/12/Form/FormProvider.js
@@ -0,0 +1,17 @@
+import {
+  FormProvider as ReactHookFormProvider,
+  useFormContext,
+} from 'react-hook-form'
+import { DevTool } from '@hookform/devtools'
+
+export const FormProvider = ({ children, ...other }) => (
+  <ReactHookFormProvider {...other}>
+    {children}
+    <DevTools />
+  </ReactHookFormProvider>
+)
+
+const DevTools = () => {
+  const { control } = useFormContext()
+  return <DevTool control={control} />
+}
diff --git a/src/examples/12/Form/Input.js b/src/examples/12/Form/Input.js
new file mode 100644
index 0000000..63deca3
--- /dev/null
+++ b/src/examples/12/Form/Input.js
@@ -0,0 +1,36 @@
+import { useFormContext, Controller } from 'react-hook-form'
+import { TextField } from '@material-ui/core'
+import { path } from 'ramda'
+
+export const Input = ({ name, label, defaultValue = '' }) => {
+  const {
+    register,
+    formState: { isSubmitting },
+    errors,
+    control,
+  } = useFormContext()
+
+  const disabled = isSubmitting
+  const helperText = path([name, 'message'], errors)
+  const error = Boolean(helperText)
+
+  return (
+    <Controller
+      as={
+        <TextField
+          name={name}
+          label={label}
+          ref={register}
+          disabled={disabled}
+          helperText={helperText}
+          error={error}
+          variant='filled'
+          fullWidth
+        />
+      }
+      name={name}
+      control={control}
+      defaultValue={defaultValue}
+    />
+  )
+}
diff --git a/src/examples/12/Form/index.js b/src/examples/12/Form/index.js
new file mode 100644
index 0000000..5caec50
--- /dev/null
+++ b/src/examples/12/Form/index.js
@@ -0,0 +1,5 @@
+export { Button } from './Button'
+export { Input } from './Input'
+export { FormProvider } from './FormProvider'
+export { useForm } from './useForm'
+export { setAsyncError } from './setAsyncError'
diff --git a/src/examples/12/Form/setAsyncError.js b/src/examples/12/Form/setAsyncError.js
new file mode 100644
index 0000000..646ebee
--- /dev/null
+++ b/src/examples/12/Form/setAsyncError.js
@@ -0,0 +1,46 @@
+import { __, compose, forEach, identity, ifElse, includes, path } from 'ramda'
+import { BAD_REQUEST, UNPROCESSABLE_ENTITY } from 'http-status'
+
+/**
+ * A function that receives a `XMLHttpRequest` error object and sets the form
+ * errors according to the error type.
+ *
+ * @callback SetErrorCallback
+ * @param {Object} error - the raw `XMLHttpRequest` error object.
+ */
+
+/**
+ * Received
+ * @param {Function} setErrorCallback - The current form `setError` function (returned from `useForm`).
+ * @param {Function} setFormWideErrorCallback - The current form `setFormWideError` function (returned from `useForm`).
+ * @returns {SetErrorCallback} callback
+ */
+export const setAsyncError = (
+  setErrorCallback,
+  setFormWideErrorCallback = identity
+) =>
+  ifElse(
+    isValidationError,
+    setValidationErrors(setErrorCallback),
+    setFormWideError(setFormWideErrorCallback)
+  )
+
+/**
+ * Checks if the error type equals to "validation", which comprehends HTTP 400 (Bad Request)
+ * and HTTP 422 (Unprocessable Entity).
+ */
+const isValidationError = compose(
+  includes(__, [BAD_REQUEST, UNPROCESSABLE_ENTITY]),
+  path(['response', 'status'])
+)
+
+const setValidationErrors = setErrorCallback =>
+  compose(
+    forEach(({ name, message }) =>
+      setErrorCallback(name, { type: 'manual', message })
+    ),
+    path(['response', 'data', 'errors'])
+  )
+
+const setFormWideError = setFormWideErrorCallback =>
+  compose(setFormWideErrorCallback, path(['response', 'data', 'message']))
diff --git a/src/examples/12/Form/useForm.js b/src/examples/12/Form/useForm.js
new file mode 100644
index 0000000..e8ecbaf
--- /dev/null
+++ b/src/examples/12/Form/useForm.js
@@ -0,0 +1,32 @@
+import { useCallback } from 'react'
+import { useState } from 'react'
+import { useForm as useRHForm } from 'react-hook-form'
+
+export const useForm = (...args) => {
+  const [formWideError, setFormWideError] = useState('')
+  const { handleSubmit: RHFhandleSubmit, ...formProps } = useRHForm(...args)
+
+  /**
+   * We need this custom submit handler because, typically, we will use a
+   * `mutateAsync` function from `react-query` to submit a form. These functions
+   * will throw any errors (422, 500, for example). Since the error is already
+   * handled by the mutation itself, we need to prevent this error from leaking.
+   *
+   * The original handler is exported as `RHFhandleSubmit`.
+   *
+   * @see {@link https://codesandbox.io/s/blissful-ride-wxxhl?file=/src/App.js}
+   * @see {@link https://codesandbox.io/s/30xos?file=/src/App.js}
+   */
+  const handleSubmit = useCallback(
+    onSubmit => RHFhandleSubmit(data => onSubmit(data).catch(() => {})),
+    [RHFhandleSubmit]
+  )
+
+  return {
+    ...formProps,
+    formWideError,
+    setFormWideError,
+    handleSubmit,
+    RHFhandleSubmit,
+  }
+}
diff --git a/src/examples/12/index.js b/src/examples/12/index.js
new file mode 100644
index 0000000..e1f417f
--- /dev/null
+++ b/src/examples/12/index.js
@@ -0,0 +1,74 @@
+import { yupResolver } from '@hookform/resolvers/yup'
+import { Grid, Collapse } from '@material-ui/core'
+import { Alert, AlertTitle } from '@material-ui/lab'
+import { useCustomMutation } from './useCustomMutation'
+import { schema } from './schema'
+import { FormProvider, useForm, Input, Button, setAsyncError } from './Form'
+import { useSnackbar } from 'notistack'
+
+export default () => {
+  const { enqueueSnackbar } = useSnackbar()
+
+  const { formWideError, setFormWideError, ...formProps } = useForm({
+    resolver: yupResolver(schema),
+  })
+
+  const { handleSubmit, setError } = formProps
+
+  const options = {
+    onSuccess: () => {
+      enqueueSnackbar('Created successfully.', {
+        variant: 'success',
+      })
+    },
+    onMutate: () => setFormWideError(''),
+    onError: error => {
+      enqueueSnackbar('Something went wrong.', {
+        variant: 'error',
+      })
+      setAsyncError(setError, setFormWideError)(error)
+    },
+  }
+
+  const { mutateAsync: created } = useCustomMutation('/created', options)
+
+  const { mutateAsync: unprocessableEntity } = useCustomMutation(
+    '/unprocessable-entity',
+    options
+  )
+
+  const { mutateAsync: conflict } = useCustomMutation('/conflict', options)
+
+  return (
+    <FormProvider {...formProps}>
+      <form onSubmit={handleSubmit(created)}>
+        <Grid container spacing={2}>
+          <Grid item xs={12}>
+            <h1>Final version</h1>
+          </Grid>
+          <Grid item xs={12}>
+            <Collapse in={Boolean(formWideError)}>
+              <Alert severity='error' onClose={() => setFormWideError('')}>
+                <AlertTitle>An error occurred</AlertTitle>
+                {formWideError}
+              </Alert>
+            </Collapse>
+          </Grid>
+          <Grid item xs={4}>
+            <Input name='firstName' defaultValue='John' label='First name' />
+          </Grid>
+          <Grid item xs={4}>
+            <Input name='lastName' defaultValue='Doe' label='Last name' />
+          </Grid>
+          <Grid item xs={4}>
+            <Button onClick={handleSubmit(created)}>Submit (201)</Button>
+            <Button onClick={handleSubmit(conflict)}>Submit (409)</Button>
+            <Button onClick={handleSubmit(unprocessableEntity)}>
+              Submit (422)
+            </Button>
+          </Grid>
+        </Grid>
+      </form>
+    </FormProvider>
+  )
+}
diff --git a/src/examples/12/schema.js b/src/examples/12/schema.js
new file mode 100644
index 0000000..17117cf
--- /dev/null
+++ b/src/examples/12/schema.js
@@ -0,0 +1,6 @@
+import * as yup from 'yup'
+
+export const schema = yup.object().shape({
+  firstName: yup.string().required(),
+  lastName: yup.string().required(),
+})
diff --git a/src/examples/12/useCustomMutation.js b/src/examples/12/useCustomMutation.js
new file mode 100644
index 0000000..b56fdae
--- /dev/null
+++ b/src/examples/12/useCustomMutation.js
@@ -0,0 +1,5 @@
+import { instance } from 'api'
+import { useMutation } from 'react-query'
+
+export const useCustomMutation = (url, options = {}) =>
+  useMutation(async () => await instance.post(url), options)
diff --git a/src/mocks/browser.js b/src/mocks/browser.js
index 968bcc5..80d6b46 100644
--- a/src/mocks/browser.js
+++ b/src/mocks/browser.js
@@ -1,5 +1,5 @@
 import { setupWorker, rest } from 'msw'
-import { CREATED, UNPROCESSABLE_ENTITY } from 'http-status'
+import { CONFLICT, CREATED, UNPROCESSABLE_ENTITY } from 'http-status'
 
 const DELAY_MS = 1000
 
@@ -23,6 +23,15 @@ const handlers = [
       })
     )
   ),
+  rest.post('/conflict', (req, res, ctx) =>
+    res(
+      ctx.delay(DELAY_MS),
+      ctx.status(CONFLICT),
+      ctx.json({
+        message: 'A conflict occurred.',
+      })
+    )
+  ),
 ]
 
 export const worker = setupWorker(...handlers)
diff --git a/yarn.lock b/yarn.lock
index 3c834ba..1d10b2b 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1369,6 +1369,16 @@
     react-is "^16.8.0 || ^17.0.0"
     react-transition-group "^4.4.0"
 
+"@material-ui/lab@^4.0.0-alpha.57":
+  version "4.0.0-alpha.57"
+  resolved "https://registry.yarnpkg.com/@material-ui/lab/-/lab-4.0.0-alpha.57.tgz#e8961bcf6449e8a8dabe84f2700daacfcafbf83a"
+  dependencies:
+    "@babel/runtime" "^7.4.4"
+    "@material-ui/utils" "^4.11.2"
+    clsx "^1.0.4"
+    prop-types "^15.7.2"
+    react-is "^16.8.0 || ^17.0.0"
+
 "@material-ui/styles@^4.11.3":
   version "4.11.3"
   resolved "https://registry.yarnpkg.com/@material-ui/styles/-/styles-4.11.3.tgz#1b8d97775a4a643b53478c895e3f2a464e8916f2"
@@ -3142,7 +3152,7 @@ cliui@^7.0.2:
     strip-ansi "^6.0.0"
     wrap-ansi "^7.0.0"
 
-clsx@^1.0.4:
+clsx@^1.0.4, clsx@^1.1.0:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/clsx/-/clsx-1.1.1.tgz#98b3134f9abbdf23b2663491ace13c5c03a73188"
 
@@ -5110,7 +5120,7 @@ hmac-drbg@^1.0.1:
     minimalistic-assert "^1.0.0"
     minimalistic-crypto-utils "^1.0.1"
 
-hoist-non-react-statics@^3.1.0, hoist-non-react-statics@^3.3.2:
+hoist-non-react-statics@^3.1.0, hoist-non-react-statics@^3.3.0, hoist-non-react-statics@^3.3.2:
   version "3.3.2"
   resolved "https://registry.yarnpkg.com/hoist-non-react-statics/-/hoist-non-react-statics-3.3.2.tgz#ece0acaf71d62c2969c2ec59feff42a4b1a85b45"
   dependencies:
@@ -7082,6 +7092,13 @@ normalize-url@^3.0.0:
   version "3.3.0"
   resolved "https://registry.yarnpkg.com/normalize-url/-/normalize-url-3.3.0.tgz#b2e1c4dc4f7c6d57743df733a4f5978d18650559"
 
+notistack@^1.0.5:
+  version "1.0.5"
+  resolved "https://registry.yarnpkg.com/notistack/-/notistack-1.0.5.tgz#239d5888105c89a9a7f26d75a07d279446dc1624"
+  dependencies:
+    clsx "^1.1.0"
+    hoist-non-react-statics "^3.3.0"
+
 npm-run-all@^4.1.5:
   version "4.1.5"
   resolved "https://registry.yarnpkg.com/npm-run-all/-/npm-run-all-4.1.5.tgz#04476202a15ee0e2e214080861bff12a51d98fba"