From mui-expert
MUI slots and slotProps API for deep component customization — replacing internal elements, custom renderers, and composition patterns
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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.
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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.
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 functionslots.valueLabel, not slots.ValueLabelimport { 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"
/>
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" />}
/>
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>
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' },
]}
/>
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',
},
}}
/>
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>
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>
When creating a custom slot component, follow these rules:
forwardRef — Required for all slot componentsimport { 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}
/>
));
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:
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',
},
}),
}}
/>
Common ownerState properties vary by component:
| Component | ownerState properties |
|---|---|
| TextField | focused, error, disabled, required, filled, size, variant, color |
| Slider | active, disabled, dragging, focusedThumbIndex, marked, orientation, value |
| Button | active, disabled, focusVisible, fullWidth, size, variant, color |
| Chip | clickable, deletable, disabled, size, variant, color |
| Badge | anchorOrigin, color, invisible, max, overlap, variant |
MUI v6 unified the customization API. Here is the mapping:
// 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' } },
}}
/>
Some components had dedicated props that are now unified under slots:
| v5 Prop | v6 Equivalent |
|---|---|
PaperComponent | slots.paper |
PopperComponent | slots.popper |
TransitionComponent | slots.transition |
BackdropComponent | slots.backdrop |
IconComponent | slots.openPickerIcon |
OpenPickerButtonProps | slotProps.openPickerButton |
InputAdornmentProps | slotProps.inputAdornment |
ToolbarComponent | slots.toolbar |
PaperProps | slotProps.paper |
PopperProps | slotProps.popper |
TransitionProps | slotProps.transition |
BackdropProps | slotProps.backdrop |
components used PascalCase keys; slots uses camelCase:
// v5
components={{ Toolbar: CustomToolbar, NoRowsOverlay: Empty }}
// v6
slots={{ toolbar: CustomToolbar, noRowsOverlay: Empty }}
MUI provides a codemod to automate migration:
npx @mui/codemod v6.0.0/preset-safe ./src
The DataGrid has the most extensive slots API in MUI. Here is a thorough reference:
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 },
},
}}
/>
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 }}
/>
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',
},
}}
/>
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
/>,
],
},
];
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 }}
/>
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' },
}}
/>
| Slot | Purpose |
|---|---|
toolbar | Top toolbar area |
footer | Bottom footer area |
columnMenu | Column header dropdown menu |
columnHeaders | Column header row container |
cell | Individual cell wrapper |
row | Row wrapper |
noRowsOverlay | Shown when rows array is empty |
noResultsOverlay | Shown when filtering returns no results |
loadingOverlay | Shown while loading={true} |
detailPanelContent | Row detail expand panel (Pro) |
detailPanelExpandIcon | Expand icon for detail panel (Pro) |
detailPanelCollapseIcon | Collapse icon for detail panel (Pro) |
pagination | Pagination controls |
filterPanel | Filter panel |
columnsPanel | Columns visibility panel |
preferencesPanel | Settings panel wrapper |
baseButton | Base Button used across the grid |
baseTextField | Base TextField used across the grid |
baseSelect | Base Select used across the grid |
baseCheckbox | Base Checkbox used across the grid |
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';
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',
},
}),
}}
/>
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,
}}
/>
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>
);
}
| Goal | Approach |
|---|---|
| Change props of an internal element | slotProps.elementName |
| Replace an internal element entirely | slots.elementName |
| Conditional props based on state | slotProps.elementName as callback |
| Custom cell in DataGrid column | renderCell on GridColDef |
| Custom toolbar/footer in DataGrid | slots.toolbar / slots.footer |
| Override base MUI components in DataGrid | slots.baseButton etc. |
| Style an internal element | slotProps.elementName.sx |
| Add test IDs to internal elements | slotProps.elementName['data-testid'] |