diff --git a/packages/frontend/src/components/grid/MkCellTooltip.vue b/packages/frontend/src/components/grid/MkCellTooltip.vue
new file mode 100644
index 0000000000..fd289c6cd9
--- /dev/null
+++ b/packages/frontend/src/components/grid/MkCellTooltip.vue
@@ -0,0 +1,35 @@
+<!--
+SPDX-FileCopyrightText: syuilo and other misskey contributors
+SPDX-License-Identifier: AGPL-3.0-only
+-->
+
+<template>
+<MkTooltip ref="tooltip" :showing="showing" :targetElement="targetElement" :maxWidth="250" @closed="emit('closed')">
+	<div :class="$style.root">
+		{{ content }}
+	</div>
+</MkTooltip>
+</template>
+
+<script lang="ts" setup>
+import { } from 'vue';
+import MkTooltip from '@/components/MkTooltip.vue';
+
+defineProps<{
+	showing: boolean;
+	content: string;
+	targetElement: HTMLElement;
+}>();
+
+const emit = defineEmits<{
+	(ev: 'closed'): void;
+}>();
+</script>
+
+<style lang="scss" module>
+.root {
+	font-size: 0.9em;
+	text-align: left;
+	text-wrap: normal;
+}
+</style>
diff --git a/packages/frontend/src/components/grid/MkDataCell.vue b/packages/frontend/src/components/grid/MkDataCell.vue
index 05a79dc725..0f6acc965a 100644
--- a/packages/frontend/src/components/grid/MkDataCell.vue
+++ b/packages/frontend/src/components/grid/MkDataCell.vue
@@ -10,9 +10,10 @@
 	<div
 		:class="[
 			$style.root,
+			[(cell.validation.valid || cell.selected) ? {} : $style.error],
 			[cell.selected ? $style.selected : {}],
 			[cell.ranged ? $style.ranged : {}],
-			[needsContentCentering ? $style.center : {}]
+			[needsContentCentering ? $style.center : {}],
 		]"
 	>
 		<div v-if="!editing" ref="contentAreaEl">
@@ -47,15 +48,12 @@
 </template>
 
 <script setup lang="ts">
-import { computed, nextTick, ref, toRefs, watch } from 'vue';
-import {
-	CellValue,
-	equalCellAddress,
-	getCellAddress,
-	GridCell,
-	GridEventEmitter,
-	Size,
-} from '@/components/grid/types.js';
+import { computed, defineAsyncComponent, nextTick, ref, shallowRef, toRefs, watch } from 'vue';
+import { GridEventEmitter, Size } from '@/components/grid/grid.js';
+import { useTooltip } from '@/scripts/use-tooltip.js';
+import * as os from '@/os.js';
+import { CellValue, GridCell } from '@/components/grid/cell.js';
+import { equalCellAddress, getCellAddress } from '@/components/grid/utils.js';
 
 const emit = defineEmits<{
 	(ev: 'operation:beginEdit', sender: GridCell): void;
@@ -70,9 +68,9 @@ const props = defineProps<{
 
 const { cell, bus } = toRefs(props);
 
-const rootEl = ref<InstanceType<typeof HTMLTableCellElement>>();
-const contentAreaEl = ref<InstanceType<typeof HTMLDivElement>>();
-const inputAreaEl = ref<InstanceType<typeof HTMLDivElement>>();
+const rootEl = shallowRef<InstanceType<typeof HTMLTableCellElement>>();
+const contentAreaEl = shallowRef<InstanceType<typeof HTMLDivElement>>();
+const inputAreaEl = shallowRef<InstanceType<typeof HTMLDivElement>>();
 
 const editing = ref<boolean>(false);
 const editingValue = ref<CellValue>(undefined);
@@ -209,6 +207,19 @@ function emitContentSizeChanged() {
 	});
 }
 
+useTooltip(rootEl, (showing) => {
+	if (cell.value.validation.valid) {
+		return;
+	}
+
+	const content = cell.value.validation.violations.map(it => it.result.message).join('\n');
+	os.popup(defineAsyncComponent(() => import('@/components/grid/MkCellTooltip.vue')), {
+		showing,
+		content,
+		targetElement: rootEl.value,
+	}, {}, 'closed');
+});
+
 </script>
 
 <style module lang="scss">
@@ -250,6 +261,10 @@ $cellHeight: 28px;
 	&.center {
 		justify-content: center;
 	}
+
+	&.error {
+		border: solid 0.5px var(--error);
+	}
 }
 
 .content {
diff --git a/packages/frontend/src/components/grid/MkDataRow.vue b/packages/frontend/src/components/grid/MkDataRow.vue
index d55bfac348..b423d1bb74 100644
--- a/packages/frontend/src/components/grid/MkDataRow.vue
+++ b/packages/frontend/src/components/grid/MkDataRow.vue
@@ -19,9 +19,10 @@
 
 <script setup lang="ts">
 import { toRefs } from 'vue';
-import { CellValue, GridCell, GridEventEmitter, GridRow, Size } from '@/components/grid/types.js';
+import { GridEventEmitter, GridRow, Size } from '@/components/grid/grid.js';
 import MkDataCell from '@/components/grid/MkDataCell.vue';
 import MkNumberCell from '@/components/grid/MkNumberCell.vue';
+import { CellValue, GridCell } from '@/components/grid/cell.js';
 
 const emit = defineEmits<{
 	(ev: 'operation:beginEdit', sender: GridCell): void;
diff --git a/packages/frontend/src/components/grid/MkGrid.vue b/packages/frontend/src/components/grid/MkGrid.vue
index e998c2caca..5347649cc1 100644
--- a/packages/frontend/src/components/grid/MkGrid.vue
+++ b/packages/frontend/src/components/grid/MkGrid.vue
@@ -36,24 +36,21 @@
 <script setup lang="ts">
 import { computed, ref, toRefs, watch } from 'vue';
 import {
-	calcCellWidth,
-	CELL_ADDRESS_NONE,
-	CellAddress,
-	CellValue, CellValueChangedEvent,
+	CellValueChangedEvent,
 	ColumnSetting,
 	DataSource,
-	equalCellAddress,
-	getCellAddress,
-	GridCell,
 	GridColumn,
 	GridEventEmitter,
 	GridRow,
 	GridState,
 	Size,
-} from '@/components/grid/types.js';
+} from '@/components/grid/grid.js';
 import MkDataRow from '@/components/grid/MkDataRow.vue';
 import MkHeaderRow from '@/components/grid/MkHeaderRow.vue';
 import copyToClipboard from '@/scripts/copy-to-clipboard.js';
+import { cellValidation, ValidateViolation } from '@/components/grid/cell-validators.js';
+import { CELL_ADDRESS_NONE, CellAddress, CellValue, GridCell } from '@/components/grid/cell.js';
+import { calcCellWidth, equalCellAddress, getCellAddress } from '@/components/grid/utils.js';
 
 const props = defineProps<{
 	columnSettings: ColumnSetting[],
@@ -61,6 +58,7 @@ const props = defineProps<{
 }>();
 
 const emit = defineEmits<{
+	(ev: 'operation:cellValidation', violation: ValidateViolation): void;
 	(ev: 'change:cellValue', event: CellValueChangedEvent): void;
 }>();
 
@@ -526,10 +524,20 @@ function onHeaderCellWidthLargest(sender: GridColumn) {
 
 function setCellValue(sender: GridCell | CellAddress, newValue: CellValue) {
 	const cellAddress = 'address' in sender ? sender.address : sender;
-	cells.value[cellAddress.row][cellAddress.col].value = newValue;
+	const cell = cells.value[cellAddress.row][cellAddress.col];
+
+	const violation = cellValidation(cell, newValue);
+	emit('operation:cellValidation', violation);
+
+	cell.validation = {
+		valid: violation.valid,
+		violations: violation.violations.filter(it => !it.valid),
+	};
+	cell.value = newValue;
+
 	emit('change:cellValue', {
-		column: columns.value[cellAddress.col],
-		row: rows.value[cellAddress.row],
+		column: cell.column,
+		row: cell.row,
 		value: newValue,
 	});
 }
@@ -709,6 +717,10 @@ function refreshData() {
 				selected: false,
 				ranged: false,
 				contentSize: { width: 0, height: 0 },
+				validation: {
+					valid: true,
+					violations: [],
+				},
 			};
 
 			rowCells.push(cell);
diff --git a/packages/frontend/src/components/grid/MkHeaderCell.vue b/packages/frontend/src/components/grid/MkHeaderCell.vue
index f3a7d4fc0b..d41dd182f2 100644
--- a/packages/frontend/src/components/grid/MkHeaderCell.vue
+++ b/packages/frontend/src/components/grid/MkHeaderCell.vue
@@ -22,7 +22,7 @@
 
 <script setup lang="ts">
 import { computed, nextTick, ref, toRefs, watch } from 'vue';
-import { GridColumn, GridEventEmitter, Size } from '@/components/grid/types.js';
+import { GridColumn, GridEventEmitter, Size } from '@/components/grid/grid.js';
 
 const emit = defineEmits<{
 	(ev: 'operation:beginWidthChange', sender: GridColumn): void;
diff --git a/packages/frontend/src/components/grid/MkHeaderRow.vue b/packages/frontend/src/components/grid/MkHeaderRow.vue
index 7fc73f1096..88158db8be 100644
--- a/packages/frontend/src/components/grid/MkHeaderRow.vue
+++ b/packages/frontend/src/components/grid/MkHeaderRow.vue
@@ -19,7 +19,7 @@
 </template>
 
 <script setup lang="ts">
-import { GridColumn, GridEventEmitter, Size } from '@/components/grid/types.js';
+import { GridColumn, GridEventEmitter, Size } from '@/components/grid/grid.js';
 import MkHeaderCell from '@/components/grid/MkHeaderCell.vue';
 import MkNumberCell from '@/components/grid/MkNumberCell.vue';
 
diff --git a/packages/frontend/src/components/grid/MkNumberCell.vue b/packages/frontend/src/components/grid/MkNumberCell.vue
index ff7954a00e..e5b1ba6301 100644
--- a/packages/frontend/src/components/grid/MkNumberCell.vue
+++ b/packages/frontend/src/components/grid/MkNumberCell.vue
@@ -5,7 +5,7 @@
 </template>
 
 <script setup lang="ts">
-import { GridRow } from '@/components/grid/types.js';
+import { GridRow } from '@/components/grid/grid.js';
 
 defineProps<{
 	content: string,
diff --git a/packages/frontend/src/components/grid/cell-validators.ts b/packages/frontend/src/components/grid/cell-validators.ts
new file mode 100644
index 0000000000..9f24998597
--- /dev/null
+++ b/packages/frontend/src/components/grid/cell-validators.ts
@@ -0,0 +1,68 @@
+import { GridColumn, GridRow } from '@/components/grid/grid.js';
+import { CellValue, GridCell } from '@/components/grid/cell.js';
+
+export type ValidatorParams = {
+	column: GridColumn;
+	row: GridRow;
+	value: CellValue;
+};
+
+export type ValidatorResult = {
+	valid: boolean;
+	message?: string;
+}
+
+export type CellValidator = {
+	name?: string;
+	validate: (params: ValidatorParams) => ValidatorResult;
+}
+
+export type ValidateViolation = {
+	valid: boolean;
+	params: ValidatorParams;
+	violations: ValidateViolationItem[];
+}
+
+export type ValidateViolationItem = {
+	valid: boolean;
+	validator: CellValidator;
+	result: ValidatorResult;
+}
+
+export function cellValidation(cell: GridCell, newValue: CellValue): ValidateViolation {
+	const { column, row } = cell;
+	const validators = column.setting.validators ?? [];
+
+	const params: ValidatorParams = {
+		column,
+		row,
+		value: newValue,
+	};
+
+	const violations: ValidateViolationItem[] = validators.map(validator => {
+		const result = validator.validate(params);
+		return {
+			valid: result.valid,
+			validator,
+			result,
+		};
+	});
+
+	return {
+		valid: violations.every(v => v.result.valid),
+		params,
+		violations,
+	};
+}
+
+export const required: CellValidator = {
+	name: 'required',
+	validate: (params: ValidatorParams): ValidatorResult => {
+		const { value } = params;
+		return {
+			valid: value !== null && value !== undefined && value !== '',
+			message: 'This field is required.',
+		};
+	},
+};
+
diff --git a/packages/frontend/src/components/grid/cell.ts b/packages/frontend/src/components/grid/cell.ts
new file mode 100644
index 0000000000..fbf05b9396
--- /dev/null
+++ b/packages/frontend/src/components/grid/cell.ts
@@ -0,0 +1,29 @@
+import { ValidateViolationItem } from '@/components/grid/cell-validators.js';
+import { GridColumn, GridRow, Size } from '@/components/grid/grid.js';
+
+export type CellValue = string | boolean | number | undefined | null
+
+export type CellAddress = {
+	row: number;
+	col: number;
+}
+
+export const CELL_ADDRESS_NONE: CellAddress = {
+	row: -1,
+	col: -1,
+};
+
+export type GridCell = {
+	address: CellAddress;
+	value: CellValue;
+	column: GridColumn;
+	row: GridRow;
+	selected: boolean;
+	ranged: boolean;
+	contentSize: Size;
+	validation: {
+		valid: boolean;
+		violations: ValidateViolationItem[];
+	}
+}
+
diff --git a/packages/frontend/src/components/grid/grid.ts b/packages/frontend/src/components/grid/grid.ts
new file mode 100644
index 0000000000..d761b6c854
--- /dev/null
+++ b/packages/frontend/src/components/grid/grid.ts
@@ -0,0 +1,45 @@
+import { EventEmitter } from 'eventemitter3';
+import { CellValidator } from '@/components/grid/cell-validators.js';
+import { CellValue } from '@/components/grid/cell.js';
+
+export type DataSource = Record<string, CellValue>;
+
+export type GridState = 'normal' | 'cellSelecting' | 'cellEditing' | 'colResizing' | 'colSelecting' | 'rowSelecting'
+
+export type Size = {
+	width: number;
+	height: number;
+}
+
+export type SizeStyle = number | 'auto' | undefined;
+
+export type ColumnType = 'text' | 'number' | 'date' | 'boolean' | 'image';
+
+export type ColumnSetting = {
+	bindTo: string;
+	title?: string;
+	type: ColumnType;
+	width: SizeStyle;
+	editable?: boolean;
+	validators?: CellValidator[];
+};
+
+export type GridColumn = {
+	index: number;
+	setting: ColumnSetting;
+	width: string;
+	contentSize: Size;
+}
+
+export type GridRow = {
+	index: number;
+}
+
+export type CellValueChangedEvent = {
+	column: GridColumn;
+	row: GridRow;
+	value: CellValue;
+}
+
+export class GridEventEmitter extends EventEmitter<{}> {
+}
diff --git a/packages/frontend/src/components/grid/types.ts b/packages/frontend/src/components/grid/types.ts
deleted file mode 100644
index 65b5f61ff4..0000000000
--- a/packages/frontend/src/components/grid/types.ts
+++ /dev/null
@@ -1,116 +0,0 @@
-import { EventEmitter } from 'eventemitter3';
-
-export type CellValue = string | boolean | number | undefined | null
-
-export type DataSource = Record<string, CellValue>;
-
-export type GridState = 'normal' | 'cellSelecting' | 'cellEditing' | 'colResizing' | 'colSelecting' | 'rowSelecting'
-
-export type RowState = 'normal' | 'added' | 'deleted'
-
-export type Size = {
-	width: number;
-	height: number;
-}
-
-export type SizeStyle = number | 'auto' | undefined;
-
-export type CellAddress = {
-	row: number;
-	col: number;
-}
-
-export const CELL_ADDRESS_NONE: CellAddress = {
-	row: -1,
-	col: -1,
-};
-
-export type GridCell = {
-	address: CellAddress;
-	value: CellValue;
-	column: GridColumn;
-	row: GridRow;
-	selected: boolean;
-	ranged: boolean;
-	contentSize: Size;
-}
-
-export type ColumnType = 'text' | 'number' | 'date' | 'boolean' | 'image';
-
-export type ColumnSetting = {
-	bindTo: string;
-	title?: string;
-	type: ColumnType;
-	width: SizeStyle;
-	editable?: boolean;
-};
-
-export type GridColumn = {
-	index: number;
-	setting: ColumnSetting;
-	width: string;
-	contentSize: Size;
-}
-
-export type GridRow = {
-	index: number;
-}
-
-export type CellValueChangedEvent = {
-	column: GridColumn;
-	row: GridRow;
-	value: CellValue;
-}
-
-export class GridEventEmitter extends EventEmitter<{}> {
-}
-
-export function isElement(elem: any): elem is HTMLElement {
-	return elem instanceof HTMLElement;
-}
-
-export function isCellElement(elem: any): elem is HTMLTableCellElement {
-	return elem instanceof HTMLTableCellElement;
-}
-
-export function isRowElement(elem: any): elem is HTMLTableRowElement {
-	return elem instanceof HTMLTableRowElement;
-}
-
-export function getCellAddress(elem: HTMLElement, parentNodeCount = 10): CellAddress {
-	let node = elem;
-	for (let i = 0; i < parentNodeCount; i++) {
-		if (isCellElement(node) && isRowElement(node.parentElement)) {
-			return {
-				// ヘッダ行ぶんを除く
-				row: node.parentElement.rowIndex - 1,
-				// 数値列ぶんを除く
-				col: node.cellIndex - 1,
-			};
-		}
-
-		if (!node.parentElement) {
-			break;
-		}
-
-		node = node.parentElement;
-	}
-
-	return CELL_ADDRESS_NONE;
-}
-
-export function equalCellAddress(a: CellAddress, b: CellAddress): boolean {
-	return a.row === b.row && a.col === b.col;
-}
-
-export function calcCellWidth(widthSetting: SizeStyle): string {
-	switch (widthSetting) {
-		case undefined:
-		case 'auto': {
-			return 'auto';
-		}
-		default: {
-			return `${widthSetting}px`;
-		}
-	}
-}
diff --git a/packages/frontend/src/components/grid/utils.ts b/packages/frontend/src/components/grid/utils.ts
new file mode 100644
index 0000000000..909749648a
--- /dev/null
+++ b/packages/frontend/src/components/grid/utils.ts
@@ -0,0 +1,49 @@
+import { SizeStyle } from '@/components/grid/types.js';
+import { CELL_ADDRESS_NONE, CellAddress } from '@/components/grid/cell.js';
+
+export function isCellElement(elem: any): elem is HTMLTableCellElement {
+	return elem instanceof HTMLTableCellElement;
+}
+
+export function isRowElement(elem: any): elem is HTMLTableRowElement {
+	return elem instanceof HTMLTableRowElement;
+}
+
+export function calcCellWidth(widthSetting: SizeStyle): string {
+	switch (widthSetting) {
+		case undefined:
+		case 'auto': {
+			return 'auto';
+		}
+		default: {
+			return `${widthSetting}px`;
+		}
+	}
+}
+
+export function getCellAddress(elem: HTMLElement, parentNodeCount = 10): CellAddress {
+	let node = elem;
+	for (let i = 0; i < parentNodeCount; i++) {
+		if (isCellElement(node) && isRowElement(node.parentElement)) {
+			return {
+				// ヘッダ行ぶんを除く
+				row: node.parentElement.rowIndex - 1,
+				// 数値列ぶんを除く
+				col: node.cellIndex - 1,
+			};
+		}
+
+		if (!node.parentElement) {
+			break;
+		}
+
+		node = node.parentElement;
+	}
+
+	return CELL_ADDRESS_NONE;
+}
+
+export function equalCellAddress(a: CellAddress, b: CellAddress): boolean {
+	return a.row === b.row && a.col === b.col;
+}
+
diff --git a/packages/frontend/src/pages/admin/custom-emojis-grid.register.vue b/packages/frontend/src/pages/admin/custom-emojis-grid.register.vue
index 5a71a0fcf1..4e56beabb2 100644
--- a/packages/frontend/src/pages/admin/custom-emojis-grid.register.vue
+++ b/packages/frontend/src/pages/admin/custom-emojis-grid.register.vue
@@ -35,6 +35,7 @@
 		<MkGrid
 			:data="convertedGridItems"
 			:columnSettings="columnSettings"
+			@operation:cellValidation="onCellValidation"
 			@change:cellValue="onChangeCellValue"
 		/>
 	</div>
@@ -43,7 +44,7 @@
 		v-if="gridItems.length > 0"
 		:class="$style.buttons"
 	>
-		<MkButton primary @click="onRegistryClicked">{{ i18n.ts.registration }}</MkButton>
+		<MkButton primary :disabled="registerButtonDisabled" @click="onRegistryClicked">{{ i18n.ts.registration }}</MkButton>
 		<MkButton @click="onClearClicked">{{ i18n.ts.clear }}</MkButton>
 	</div>
 </div>
@@ -56,7 +57,7 @@ import * as Misskey from 'misskey-js';
 import { misskeyApi } from '@/scripts/misskey-api.js';
 import { GridItem, IGridItem } from '@/pages/admin/custom-emojis-grid.impl.js';
 import MkGrid from '@/components/grid/MkGrid.vue';
-import { CellValueChangedEvent, ColumnSetting } from '@/components/grid/types.js';
+import { CellValueChangedEvent, ColumnSetting } from '@/components/grid/grid.js';
 import { i18n } from '@/i18n.js';
 import MkSelect from '@/components/MkSelect.vue';
 import { uploadFile } from '@/scripts/upload.js';
@@ -65,6 +66,7 @@ import { defaultStore } from '@/store.js';
 import MkFolder from '@/components/MkFolder.vue';
 import MkButton from '@/components/MkButton.vue';
 import * as os from '@/os.js';
+import { required, ValidateViolation } from '@/components/grid/cell-validators.js';
 
 type FolderItem = {
 	id?: string;
@@ -78,8 +80,8 @@ const emit = defineEmits<{
 }>();
 
 const columnSettings: ColumnSetting[] = [
-	{ bindTo: 'url', title: '🎨', type: 'image', editable: false, width: 50 },
-	{ bindTo: 'name', title: 'name', type: 'text', editable: true, width: 140 },
+	{ bindTo: 'url', title: '🎨', type: 'image', editable: false, width: 50, validators: [required] },
+	{ bindTo: 'name', title: 'name', type: 'text', editable: true, width: 140, validators: [required] },
 	{ bindTo: 'category', title: 'category', type: 'text', editable: true, width: 140 },
 	{ bindTo: 'aliases', title: 'aliases', type: 'text', editable: true, width: 140 },
 	{ bindTo: 'license', title: 'license', type: 'text', editable: true, width: 140 },
@@ -92,6 +94,8 @@ const uploadFolders = ref<FolderItem[]>([]);
 const gridItems = ref<IGridItem[]>([]);
 const selectedFolderId = ref(defaultStore.state.uploadFolder);
 const keepOriginalUploading = ref(defaultStore.state.keepOriginalUploading);
+const registerButtonDisabled = ref<boolean>(false);
+
 const convertedGridItems = computed(() => gridItems.value.map(it => it as Record<string, any>));
 
 async function onRegistryClicked() {
@@ -180,6 +184,11 @@ async function onDrop(ev: DragEvent) {
 	}
 }
 
+function onCellValidation(violation: ValidateViolation) {
+	console.log(violation);
+	registerButtonDisabled.value = !violation.valid;
+}
+
 function onChangeCellValue(event: CellValueChangedEvent) {
 	console.log(event);
 	const item = gridItems.value[event.row.index];