MUI Slots & slotProps API

The slots/slotProps pattern is MUI's primary mechanism for deep component customization. It lets you replace internal sub-components, inject custom renderers, and pass props to every layer of a compound component without wrapper hacks.

1. What Are Slots?

Every compound MUI component is built from smaller internal elements. The slots prop lets you swap any of those internal elements with your own component. The slotProps prop lets you pass additional props to each slot — whether you replaced it or not.

// Before (MUI v5 — deprecated)
<Autocomplete
  PaperComponent={CustomPaper}
  componentsProps={{ paper: { elevation: 8 } }}
/>

// After (MUI v6+ — slots API)
<Autocomplete
  slots={{ paper: CustomPaper }}
  slotProps={{ paper: { elevation: 8 } }}
/>

Key rules:

• slots accepts component references (not JSX elements)
• slotProps accepts either a plain object or a callback function
• Slot names are camelCase: slots.valueLabel, not slots.ValueLabel
• The component you provide receives all the props that the default slot component would receive — spread them through

2. Common Slot Patterns by Component

TextField

import { TextField, InputBase, FormHelperText } from '@mui/material';

// Replace the underlying input element
<TextField
  label="Custom Input"
  slots={{
    input: InputBase,
    inputLabel: CustomLabel,
  }}
  slotProps={{
    input: {
      sx: { borderRadius: 2, bgcolor: 'grey.50' },
      'aria-describedby': 'helper-text',
    },
    inputLabel: {
      shrink: true,
      sx: { fontWeight: 600 },
    },
    formHelperText: {
      sx: { fontSize: '0.75rem', color: 'warning.main' },
    },
    htmlInput: {
      maxLength: 100,
      pattern: '[A-Za-z]+',
    },
  }}
  helperText="Letters only, max 100 chars"
/>

Autocomplete

import {
  Autocomplete,
  TextField,
  Paper,
  Popper,
  type PaperProps,
  type PopperProps,
  type AutocompleteRenderOptionState,
} from '@mui/material';
import { forwardRef } from 'react';

// Custom paper with shadow and border radius
const StyledPaper = forwardRef<HTMLDivElement, PaperProps>((props, ref) => (
  <Paper
    {...props}
    ref={ref}
    elevation={8}
    sx={{ borderRadius: 2, border: '1px solid', borderColor: 'divider' }}
  />
));
StyledPaper.displayName = 'StyledPaper';

// Custom popper with width matching
const WidePopper = forwardRef<HTMLDivElement, PopperProps>((props, ref) => (
  <Popper {...props} ref={ref} placement="bottom-start" sx={{ minWidth: 400 }} />
));
WidePopper.displayName = 'WidePopper';

<Autocomplete
  options={options}
  slots={{
    paper: StyledPaper,
    popper: WidePopper,
    listbox: CustomListbox,
  }}
  slotProps={{
    paper: { 'data-testid': 'autocomplete-dropdown' },
    popper: { modifiers: [{ name: 'offset', options: { offset: [0, 8] } }] },
    listbox: { sx: { maxHeight: 300, '& .MuiAutocomplete-option': { py: 1 } } },
    chip: { size: 'small', color: 'primary', variant: 'outlined' },
    clearIndicator: { sx: { color: 'error.main' } },
  }}
  renderInput={(params) => <TextField {...params} label="Search" />}
/>

Select

import { Select, MenuItem } from '@mui/material';

<Select
  value={value}
  onChange={handleChange}
  slots={{
    root: CustomSelectRoot,
  }}
  slotProps={{
    listbox: {
      sx: {
        maxHeight: 250,
        '& .MuiMenuItem-root': {
          borderRadius: 1,
          mx: 0.5,
        },
      },
    },
  }}
>
  <MenuItem value={10}>Ten</MenuItem>
  <MenuItem value={20}>Twenty</MenuItem>
</Select>

Slider

import { Slider, type SliderThumbSlotProps } from '@mui/material';
import { forwardRef } from 'react';

// Custom thumb with tooltip-style display
const CustomThumb = forwardRef<HTMLSpanElement, SliderThumbSlotProps>(
  (props, ref) => {
    const { children, className, ...other } = props;
    return (
      <span ref={ref} className={className} {...other}>
        {children}
        <span style={{
          position: 'absolute',
          top: -28,
          fontSize: 12,
          fontWeight: 700,
          background: '#1976d2',
          color: '#fff',
          borderRadius: 4,
          padding: '2px 6px',
        }}>
          {props['aria-valuenow']}
        </span>
      </span>
    );
  }
);
CustomThumb.displayName = 'CustomThumb';

<Slider
  value={sliderValue}
  onChange={handleSliderChange}
  slots={{
    thumb: CustomThumb,
    track: CustomTrack,
    rail: CustomRail,
    valueLabel: CustomValueLabel,
    mark: CustomMark,
    markLabel: CustomMarkLabel,
  }}
  slotProps={{
    thumb: {
      'data-testid': 'custom-thumb',
      sx: { width: 24, height: 24 },
    },
    track: {
      sx: { height: 8, borderRadius: 4 },
    },
    rail: {
      sx: { height: 8, borderRadius: 4, opacity: 0.3 },
    },
    valueLabel: {
      sx: { bgcolor: 'primary.dark', fontSize: 12 },
    },
  }}
  marks={[
    { value: 0, label: '0' },
    { value: 50, label: '50' },
    { value: 100, label: '100' },
  ]}
/>

DatePicker

import { DatePicker } from '@mui/x-date-pickers/DatePicker';
import { PickersDay, type PickersDayProps } from '@mui/x-date-pickers/PickersDay';
import { type Dayjs } from 'dayjs';

// Highlight weekends
function CustomDay(props: PickersDayProps<Dayjs>) {
  const { day, ...other } = props;
  const isWeekend = day.day() === 0 || day.day() === 6;

  return (
    <PickersDay
      {...other}
      day={day}
      sx={{
        ...(isWeekend && {
          bgcolor: 'warning.light',
          '&:hover': { bgcolor: 'warning.main' },
        }),
      }}
    />
  );
}

<DatePicker
  label="Select date"
  value={dateValue}
  onChange={handleDateChange}
  slots={{
    day: CustomDay,
    field: CustomField,
    textField: CustomTextField,
    actionBar: CustomActionBar,
    toolbar: CustomToolbar,
    layout: CustomLayout,
  }}
  slotProps={{
    day: {
      sx: { borderRadius: 1 },
    },
    textField: {
      size: 'small',
      variant: 'filled',
      helperText: 'MM/DD/YYYY',
    },
    actionBar: {
      actions: ['clear', 'today', 'accept'],
    },
    toolbar: {
      hidden: false,
      toolbarFormat: 'ddd, MMM D',
    },
    popper: {
      placement: 'bottom-end',
    },
  }}
/>

Dialog

import { Dialog, Backdrop, type BackdropProps } from '@mui/material';
import { forwardRef } from 'react';

const BlurredBackdrop = forwardRef<HTMLDivElement, BackdropProps>((props, ref) => (
  <Backdrop
    {...props}
    ref={ref}
    sx={{
      backdropFilter: 'blur(8px)',
      backgroundColor: 'rgba(0, 0, 0, 0.3)',
    }}
  />
));
BlurredBackdrop.displayName = 'BlurredBackdrop';

<Dialog
  open={open}
  onClose={handleClose}
  slots={{
    backdrop: BlurredBackdrop,
    transition: Fade,
  }}
  slotProps={{
    backdrop: {
      timeout: 500,
      'data-testid': 'dialog-backdrop',
    },
    paper: {
      sx: {
        borderRadius: 3,
        boxShadow: 24,
        minWidth: 400,
      },
      elevation: 0,
    },
  }}
>
  <DialogTitle>Confirm Action</DialogTitle>
  <DialogContent>Are you sure?</DialogContent>
</Dialog>

Tooltip

import { Tooltip, Popper, type PopperProps } from '@mui/material';
import { forwardRef } from 'react';

const ThemedPopper = forwardRef<HTMLDivElement, PopperProps>((props, ref) => (
  <Popper
    {...props}
    ref={ref}
    sx={{
      '& .MuiTooltip-tooltip': {
        bgcolor: 'primary.dark',
        fontSize: 14,
        borderRadius: 2,
        px: 2,
        py: 1,
      },
      '& .MuiTooltip-arrow': {
        color: 'primary.dark',
      },
    }}
  />
));
ThemedPopper.displayName = 'ThemedPopper';

<Tooltip
  title="Detailed description here"
  arrow
  slots={{
    popper: ThemedPopper,
  }}
  slotProps={{
    popper: {
      modifiers: [{ name: 'offset', options: { offset: [0, -4] } }],
    },
    arrow: {
      sx: { color: 'primary.dark' },
    },
    tooltip: {
      sx: { maxWidth: 300 },
    },
    transition: {
      timeout: 200,
    },
  }}
>
  <IconButton>
    <InfoIcon />
  </IconButton>
</Tooltip>

3. Custom Slot Components

When creating a custom slot component, follow these rules:

1. Forward the ref — MUI needs refs for positioning (Popper, Tooltip) and focus management
2. Spread all props — The parent component passes required props (event handlers, ARIA attributes, styles); dropping them breaks functionality
3. Use forwardRef — Required for all slot components

import { forwardRef, type HTMLAttributes } from 'react';
import { Paper, type PaperProps } from '@mui/material';

// CORRECT: Forward ref, spread props, then add customizations
const CustomPaper = forwardRef<HTMLDivElement, PaperProps>((props, ref) => {
  const { children, sx, ...rest } = props;

  return (
    <Paper
      ref={ref}
      elevation={8}
      sx={[
        { borderRadius: 2, border: '2px solid', borderColor: 'primary.main' },
        // Merge incoming sx (may be from slotProps)
        ...(Array.isArray(sx) ? sx : [sx]),
      ]}
      {...rest}
    >
      {children}
    </Paper>
  );
});
CustomPaper.displayName = 'CustomPaper';

// Usage
<Autocomplete
  slots={{ paper: CustomPaper }}
  slotProps={{ paper: { sx: { minWidth: 300 } } }} // This sx merges with the slot's sx
  renderInput={(params) => <TextField {...params} label="Search" />}
/>

Merging sx correctly:

When your custom slot defines its own sx and you also want slotProps.*.sx to apply, merge them using the array syntax:

const MySlot = forwardRef<HTMLDivElement, BoxProps>(({ sx, ...props }, ref) => (
  <Box
    ref={ref}
    sx={[
      { p: 2, bgcolor: 'grey.100' },           // slot defaults
      ...(Array.isArray(sx) ? sx : [sx]),        // incoming overrides
    ]}
    {...props}
  />
));

4. slotProps Callback Form

Instead of a static object, pass a function to slotProps to compute props based on the component's current state (the "owner state"):

import { TextField } from '@mui/material';

<TextField
  label="Dynamic styling"
  slotProps={{
    // Callback receives ownerState with component internal state
    input: (ownerState) => ({
      sx: {
        fontWeight: ownerState.focused ? 700 : 400,
        bgcolor: ownerState.error ? 'error.light' : 'transparent',
        transition: 'all 0.2s ease',
      },
    }),
    inputLabel: (ownerState) => ({
      sx: {
        color: ownerState.focused ? 'primary.main' : 'text.secondary',
        fontSize: ownerState.shrink ? 12 : 16,
      },
    }),
  }}
/>

The callback pattern is especially useful for:

• Conditional styling based on focused/error/disabled state
• Computed ARIA attributes based on value
• Dynamic classes that depend on the component's internal state

import { Slider } from '@mui/material';

<Slider
  slotProps={{
    thumb: (ownerState) => ({
      sx: {
        // Change thumb color at extremes
        bgcolor: ownerState.value === 100
          ? 'success.main'
          : ownerState.value === 0
            ? 'error.main'
            : 'primary.main',
        width: ownerState.active ? 28 : 20,
        height: ownerState.active ? 28 : 20,
        transition: 'width 0.1s, height 0.1s',
      },
    }),
    valueLabel: (ownerState) => ({
      sx: {
        bgcolor: ownerState.value > 80 ? 'success.dark' : 'primary.dark',
      },
    }),
  }}
/>

Owner State Properties

Common ownerState properties vary by component:

5. Migration from components/componentsProps (v5 to v6)

MUI v6 unified the customization API. Here is the mapping:

Prop Renames

// v5 (deprecated)
<DataGrid
  components={{
    Toolbar: CustomToolbar,
    Footer: CustomFooter,
    NoRowsOverlay: EmptyState,
  }}
  componentsProps={{
    toolbar: { showQuickFilter: true },
    footer: { sx: { bgcolor: 'grey.50' } },
  }}
/>

// v6+ (current)
<DataGrid
  slots={{
    toolbar: CustomToolbar,
    footer: CustomFooter,
    noRowsOverlay: EmptyState,
  }}
  slotProps={{
    toolbar: { showQuickFilter: true },
    footer: { sx: { bgcolor: 'grey.50' } },
  }}
/>

Named Props to Slots

Some components had dedicated props that are now unified under slots:

Casing Change

components used PascalCase keys; slots uses camelCase:

// v5
components={{ Toolbar: CustomToolbar, NoRowsOverlay: Empty }}

// v6
slots={{ toolbar: CustomToolbar, noRowsOverlay: Empty }}

Codemod

MUI provides a codemod to automate migration:

npx @mui/codemod v6.0.0/preset-safe ./src

6. DataGrid Slots (Comprehensive)

The DataGrid has the most extensive slots API in MUI. Here is a thorough reference:

Toolbar

import {
  DataGrid,
  GridToolbarContainer,
  GridToolbarExport,
  GridToolbarFilterButton,
  GridToolbarQuickFilter,
  type GridSlots,
} from '@mui/x-data-grid';

function CustomToolbar() {
  return (
    <GridToolbarContainer sx={{ p: 1, gap: 1 }}>
      <GridToolbarFilterButton />
      <GridToolbarExport />
      <Box sx={{ flexGrow: 1 }} />
      <GridToolbarQuickFilter
        debounceMs={300}
        sx={{ width: 250 }}
      />
      <Button
        size="small"
        startIcon={<AddIcon />}
        onClick={handleAddRow}
      >
        Add Row
      </Button>
    </GridToolbarContainer>
  );
}

<DataGrid
  rows={rows}
  columns={columns}
  slots={{
    toolbar: CustomToolbar,
  }}
  slotProps={{
    toolbar: {
      showQuickFilter: true,
      quickFilterProps: { debounceMs: 300 },
    },
  }}
/>

Footer

import { GridFooterContainer, type GridSlotsComponentsProps } from '@mui/x-data-grid';

function CustomFooter(props: NonNullable<GridSlotsComponentsProps['footer']>) {
  const { selectedRowCount, totalRowCount } = props;

  return (
    <GridFooterContainer sx={{ justifyContent: 'space-between', px: 2 }}>
      <Typography variant="body2" color="text.secondary">
        {selectedRowCount > 0
          ? `${selectedRowCount} of ${totalRowCount} selected`
          : `${totalRowCount} total rows`}
      </Typography>
      <Box sx={{ display: 'flex', gap: 1 }}>
        <Button size="small" onClick={handleExport}>Export CSV</Button>
        <Button size="small" onClick={handlePrint}>Print</Button>
      </Box>
    </GridFooterContainer>
  );
}

<DataGrid
  rows={rows}
  columns={columns}
  slots={{ footer: CustomFooter }}
/>

No Rows & Loading Overlays

function NoRowsOverlay() {
  return (
    <Box
      sx={{
        display: 'flex',
        flexDirection: 'column',
        alignItems: 'center',
        justifyContent: 'center',
        height: '100%',
        gap: 2,
      }}
    >
      <SearchOffIcon sx={{ fontSize: 64, color: 'text.disabled' }} />
      <Typography variant="h6" color="text.secondary">
        No results found
      </Typography>
      <Typography variant="body2" color="text.disabled">
        Try adjusting your search or filter criteria
      </Typography>
    </Box>
  );
}

function LoadingOverlay() {
  return (
    <Box
      sx={{
        display: 'flex',
        alignItems: 'center',
        justifyContent: 'center',
        height: '100%',
      }}
    >
      <CircularProgress size={40} />
      <Typography sx={{ ml: 2 }}>Loading data...</Typography>
    </Box>
  );
}

<DataGrid
  rows={rows}
  columns={columns}
  loading={isLoading}
  slots={{
    noRowsOverlay: NoRowsOverlay,
    noResultsOverlay: NoRowsOverlay,
    loadingOverlay: LoadingOverlay,
  }}
  slotProps={{
    loadingOverlay: {
      variant: 'skeleton',
      noRowsVariant: 'skeleton',
    },
  }}
/>

Custom Cell Renderer via renderCell vs Slots

For per-column cell customization, use renderCell on the column definition. For global cell wrapper customization, use slots:

import {
  type GridColDef,
  type GridRenderCellParams,
  type GridCellParams,
} from '@mui/x-data-grid';

// Per-column: renderCell
const columns: GridColDef[] = [
  {
    field: 'status',
    headerName: 'Status',
    width: 150,
    renderCell: (params: GridRenderCellParams) => (
      <Chip
        label={params.value}
        color={params.value === 'active' ? 'success' : 'default'}
        size="small"
        variant="outlined"
      />
    ),
  },
  {
    field: 'progress',
    headerName: 'Progress',
    width: 200,
    renderCell: (params: GridRenderCellParams<any, number>) => (
      <Box sx={{ width: '100%', display: 'flex', alignItems: 'center', gap: 1 }}>
        <LinearProgress
          variant="determinate"
          value={params.value ?? 0}
          sx={{ flexGrow: 1, height: 8, borderRadius: 4 }}
        />
        <Typography variant="caption">{params.value}%</Typography>
      </Box>
    ),
  },
  {
    field: 'actions',
    headerName: 'Actions',
    type: 'actions',
    width: 120,
    getActions: (params) => [
      <GridActionsCellItem
        key="edit"
        icon={<EditIcon />}
        label="Edit"
        onClick={() => handleEdit(params.id)}
      />,
      <GridActionsCellItem
        key="delete"
        icon={<DeleteIcon />}
        label="Delete"
        onClick={() => handleDelete(params.id)}
        showInMenu
      />,
    ],
  },
];

Column Menu

import {
  GridColumnMenu,
  type GridColumnMenuProps,
  GridColumnMenuFilterItem,
  GridColumnMenuSortItem,
  GridColumnMenuColumnsItem,
} from '@mui/x-data-grid';

function CustomColumnMenu(props: GridColumnMenuProps) {
  return (
    <GridColumnMenu
      {...props}
      slots={{
        columnMenuSortItem: GridColumnMenuSortItem,
        columnMenuFilterItem: GridColumnMenuFilterItem,
        columnMenuColumnsItem: GridColumnMenuColumnsItem,
      }}
      slotProps={{
        columnMenuSortItem: { displayOrder: 0 },
        columnMenuFilterItem: { displayOrder: 10 },
        columnMenuColumnsItem: { displayOrder: 20 },
      }}
    />
  );
}

<DataGrid
  rows={rows}
  columns={columns}
  slots={{ columnMenu: CustomColumnMenu }}
/>

Base Component Overrides

DataGrid allows overriding the base MUI components it uses internally:

<DataGrid
  rows={rows}
  columns={columns}
  slots={{
    baseButton: CustomButton,
    baseTextField: CustomTextField,
    baseSelect: CustomSelect,
    baseCheckbox: CustomCheckbox,
    baseSwitch: CustomSwitch,
    baseChip: CustomChip,
    baseTooltip: CustomTooltip,
    basePopper: CustomPopper,
    baseInputAdornment: CustomInputAdornment,
    baseIconButton: CustomIconButton,
  }}
  slotProps={{
    baseButton: { variant: 'outlined', size: 'small' },
    baseTextField: { variant: 'filled', size: 'small' },
    baseCheckbox: { color: 'secondary' },
  }}
/>

Complete DataGrid Slot Reference

7. TypeScript Typing

Typing Custom Slot Components

Use SlotComponentProps to correctly type a custom slot:

import { type SlotComponentProps } from '@mui/base/utils';
import { type PaperProps } from '@mui/material/Paper';
import { type AutocompleteOwnerState } from '@mui/material/Autocomplete';
import { forwardRef } from 'react';

// Method 1: Use the exact MUI prop type directly
const TypedPaper = forwardRef<HTMLDivElement, PaperProps>((props, ref) => (
  <Paper {...props} ref={ref} elevation={8} />
));
TypedPaper.displayName = 'TypedPaper';

// Method 2: Use SlotComponentProps for full owner state access
type AutocompletePaperSlotProps = SlotComponentProps<
  typeof Paper,
  {}, // additional props you want
  AutocompleteOwnerState<string, false, false, false>
>;

const TypedPaperWithOwnerState = forwardRef<HTMLDivElement, AutocompletePaperSlotProps>(
  (props, ref) => {
    const { ownerState, ...rest } = props;
    return (
      <Paper
        {...rest}
        ref={ref}
        elevation={ownerState?.focused ? 12 : 4}
      />
    );
  }
);
TypedPaperWithOwnerState.displayName = 'TypedPaperWithOwnerState';

Typing slotProps Callbacks

import { type TextFieldOwnerState } from '@mui/material/TextField';
import { type SliderOwnerState } from '@mui/material/Slider';

// The callback signature is (ownerState: OwnerState) => SlotProps
<TextField
  slotProps={{
    input: (ownerState: TextFieldOwnerState) => ({
      sx: {
        bgcolor: ownerState.error ? 'error.light' : 'background.paper',
      },
    }),
  }}
/>

<Slider
  slotProps={{
    thumb: (ownerState: SliderOwnerState) => ({
      style: {
        backgroundColor: ownerState.active ? '#ff0000' : '#1976d2',
      },
    }),
  }}
/>

Typing DataGrid Slots

import {
  DataGrid,
  type GridSlots,
  type GridSlotsComponentsProps,
  type GridToolbarContainerProps,
} from '@mui/x-data-grid';

// Custom toolbar with typed props
interface CustomToolbarProps extends GridToolbarContainerProps {
  onAddClick: () => void;
  title: string;
}

function CustomToolbar({ onAddClick, title, ...props }: CustomToolbarProps) {
  return (
    <GridToolbarContainer {...props}>
      <Typography variant="h6">{title}</Typography>
      <Box sx={{ flexGrow: 1 }} />
      <Button onClick={onAddClick}>Add</Button>
    </GridToolbarContainer>
  );
}

// Pass custom props through slotProps
<DataGrid
  rows={rows}
  columns={columns}
  slots={{
    toolbar: CustomToolbar as GridSlots['toolbar'],
  }}
  slotProps={{
    toolbar: {
      onAddClick: handleAddRow,
      title: 'User Management',
    } as CustomToolbarProps,
  }}
/>

Extending Slot Types for Custom Components

When building a reusable component that accepts slots itself:

import { type ElementType, type ComponentPropsWithRef } from 'react';

// Define your own slots interface
interface MyComponentSlots {
  root?: ElementType;
  header?: ElementType;
  content?: ElementType;
  footer?: ElementType;
}

// Define slotProps to match
interface MyComponentSlotProps {
  root?: ComponentPropsWithRef<'div'>;
  header?: ComponentPropsWithRef<'div'> & { title?: string };
  content?: ComponentPropsWithRef<'div'>;
  footer?: ComponentPropsWithRef<'div'>;
}

interface MyComponentProps {
  slots?: MyComponentSlots;
  slotProps?: MyComponentSlotProps;
  children: React.ReactNode;
}

function MyComponent({ slots, slotProps, children }: MyComponentProps) {
  const Root = slots?.root ?? 'div';
  const Header = slots?.header ?? 'div';
  const Content = slots?.content ?? 'div';
  const Footer = slots?.footer ?? 'div';

  return (
    <Root {...slotProps?.root}>
      <Header {...slotProps?.header} />
      <Content {...slotProps?.content}>{children}</Content>
      <Footer {...slotProps?.footer} />
    </Root>
  );
}

Quick Reference: When to Use What