diff --git a/src-ui/src/app/components/common/custom-fields-query-dropdown/custom-fields-query-dropdown.component.html b/src-ui/src/app/components/common/custom-fields-query-dropdown/custom-fields-query-dropdown.component.html
index ef63881b9..98b41e3d6 100644
--- a/src-ui/src/app/components/common/custom-fields-query-dropdown/custom-fields-query-dropdown.component.html
+++ b/src-ui/src/app/components/common/custom-fields-query-dropdown/custom-fields-query-dropdown.component.html
@@ -42,13 +42,13 @@
       bindValue="id"
     ></ng-select>
     <select class="w-25 form-select" [(ngModel)]="query.operator" [disabled]="disabled">
-      <option *ngFor="let operator of getOperatorsForField(query.field)" [ngValue]="operator">{{operator}}</option>
+      <option *ngFor="let operator of getOperatorsForField(query.field)" [ngValue]="operator.value">{{operator.label}}</option>
     </select>
     @switch (query.operator) {
-      @case ('exists') {
+      @case (CustomFieldQueryOperator.Exists) {
         <select class="w-25 form-select rounded-end" [(ngModel)]="query.value" [disabled]="disabled">
-          <option value="true" i18n>true</option>
-          <option value="false" i18n>false</option>
+          <option value="true" i18n>True</option>
+          <option value="false" i18n>False</option>
         </select>
       }
       @default {
diff --git a/src-ui/src/app/components/common/custom-fields-query-dropdown/custom-fields-query-dropdown.component.ts b/src-ui/src/app/components/common/custom-fields-query-dropdown/custom-fields-query-dropdown.component.ts
index 8efdb6a71..b4baaa79d 100644
--- a/src-ui/src/app/components/common/custom-fields-query-dropdown/custom-fields-query-dropdown.component.ts
+++ b/src-ui/src/app/components/common/custom-fields-query-dropdown/custom-fields-query-dropdown.component.ts
@@ -1,136 +1,18 @@
 import { Component, EventEmitter, Input, Output } from '@angular/core'
 import { Subject, first, takeUntil } from 'rxjs'
 import { CustomField } from 'src/app/data/custom-field'
+import {
+  CustomFieldQueryAtom,
+  CustomFieldQueryExpression,
+  CustomFieldQueryElementType,
+  CustomFieldQueryOperator,
+  CUSTOM_FIELD_QUERY_OPERATOR_GROUPS_BY_TYPE,
+  CUSTOM_FIELD_QUERY_OPERATORS_BY_GROUP,
+  CustomFieldQueryOperatorGroups,
+  CUSTOM_FIELD_QUERY_OPERATOR_LABELS,
+} from 'src/app/data/custom-field-query'
 import { CustomFieldsService } from 'src/app/services/rest/custom-fields.service'
 
-export enum CustomFieldQueryLogicalOperator {
-  And = 'AND',
-  Or = 'OR',
-  Not = 'NOT',
-}
-
-export enum CustomFieldQueryElementType {
-  Atom = 'Atom',
-  Expression = 'Expression',
-}
-
-export class CustomFieldQueryElement {
-  public readonly type: CustomFieldQueryElementType
-  public changed: Subject<CustomFieldQueryElement>
-
-  constructor(type: CustomFieldQueryElementType) {
-    this.type = type
-    this.changed = new Subject<CustomFieldQueryElement>()
-  }
-
-  public serialize() {
-    throw new Error('Implemented in subclass')
-  }
-
-  public get isValid(): boolean {
-    throw new Error('Implemented in subclass')
-  }
-
-  protected _operator: string = null
-  set operator(value: string) {
-    this._operator = value
-    this.changed.next(this)
-  }
-  get operator(): string {
-    return this._operator
-  }
-
-  protected _value:
-    | string
-    | CustomFieldQueryAtom[]
-    | CustomFieldQueryExpression[] = null
-  set value(
-    value: string | CustomFieldQueryAtom[] | CustomFieldQueryExpression[]
-  ) {
-    this._value = value
-    this.changed.next(this)
-  }
-  get value(): string | CustomFieldQueryAtom[] | CustomFieldQueryExpression[] {
-    return this._value
-  }
-}
-
-export class CustomFieldQueryAtom extends CustomFieldQueryElement {
-  protected _field: string
-  set field(value: string) {
-    this._field = value
-    if (this.isValid) this.changed.next(this)
-  }
-  get field(): string {
-    return this._field
-  }
-
-  constructor(queryArray: [string, string, string] = [null, null, null]) {
-    super(CustomFieldQueryElementType.Atom)
-    ;[this._field, this._operator, this._value] = queryArray
-  }
-
-  public serialize() {
-    return [this._field, this._operator, this._value]
-  }
-
-  public get isValid(): boolean {
-    return !!(this._field && this._operator && this._value !== null)
-  }
-}
-
-export class CustomFieldQueryExpression extends CustomFieldQueryElement {
-  constructor(
-    expressionArray: [CustomFieldQueryLogicalOperator, any[]] = [
-      CustomFieldQueryLogicalOperator.And,
-      null,
-    ]
-  ) {
-    super(CustomFieldQueryElementType.Expression)
-    ;[this._operator] = expressionArray
-    let values = expressionArray[1]
-    if (!values) {
-      this._value = []
-    } else if (values?.length > 0 && values[0] instanceof Array) {
-      this._value = values.map((value) => {
-        if (value.length === 3) {
-          const atom = new CustomFieldQueryAtom(value)
-          atom.changed.subscribe(() => {
-            this.changed.next(this)
-          })
-          return atom
-        } else {
-          const expression = new CustomFieldQueryExpression(value)
-          expression.changed.subscribe(() => {
-            this.changed.next(this)
-          })
-          return expression
-        }
-      })
-    } else {
-      this._value = [new CustomFieldQueryExpression(values as any)]
-    }
-  }
-
-  public serialize() {
-    let value
-    if (this._value instanceof Array) {
-      value = this._value.map((atom) => atom.serialize())
-    } else {
-      value = value.serialize()
-    }
-    return [this._operator, value]
-  }
-
-  public get isValid(): boolean {
-    return (
-      this._operator &&
-      this._value.length > 0 &&
-      (this._value as any[]).every((v) => v.isValid)
-    )
-  }
-}
-
 export class CustomFieldQueriesModel {
   public queries: Array<CustomFieldQueryAtom | CustomFieldQueryExpression> = []
 
@@ -234,6 +116,7 @@ export class CustomFieldQueriesModel {
 })
 export class CustomFieldsQueryDropdownComponent {
   public CustomFieldQueryComponentType = CustomFieldQueryElementType
+  public CustomFieldQueryOperator = CustomFieldQueryOperator
 
   @Input()
   title: string
@@ -317,8 +200,21 @@ export class CustomFieldsQueryDropdownComponent {
     this.selectionModel.clear()
   }
 
-  getOperatorsForField(field: CustomField): string[] {
-    return ['exact', 'in', 'icontains', 'isnull', 'exists']
-    // TODO: implement this
+  getOperatorsForField(
+    fieldID: number
+  ): Array<{ value: string; label: string }> {
+    const field = this.customFields.find((field) => field.id === fieldID)
+    const groups: CustomFieldQueryOperatorGroups[] =
+      CUSTOM_FIELD_QUERY_OPERATOR_GROUPS_BY_TYPE[field.data_type]
+    if (!groups) {
+      return []
+    }
+    const operators = groups.flatMap(
+      (group) => CUSTOM_FIELD_QUERY_OPERATORS_BY_GROUP[group]
+    )
+    return operators.map((operator) => ({
+      value: operator,
+      label: CUSTOM_FIELD_QUERY_OPERATOR_LABELS[operator],
+    }))
   }
 }
diff --git a/src-ui/src/app/components/document-list/filter-editor/filter-editor.component.ts b/src-ui/src/app/components/document-list/filter-editor/filter-editor.component.ts
index 5a64f8ead..cf160bd19 100644
--- a/src-ui/src/app/components/document-list/filter-editor/filter-editor.component.ts
+++ b/src-ui/src/app/components/document-list/filter-editor/filter-editor.component.ts
@@ -94,11 +94,10 @@ import { CustomFieldsService } from 'src/app/services/rest/custom-fields.service
 import { CustomField } from 'src/app/data/custom-field'
 import { SearchService } from 'src/app/services/rest/search.service'
 import {
-  CustomFieldQueriesModel,
-  CustomFieldQueryAtom,
   CustomFieldQueryExpression,
-  CustomFieldQueryLogicalOperator,
-} from '../../common/custom-fields-query-dropdown/custom-fields-query-dropdown.component'
+  CustomFieldQueryAtom,
+} from 'src/app/data/custom-field-query'
+import { CustomFieldQueriesModel } from '../../common/custom-fields-query-dropdown/custom-fields-query-dropdown.component'
 
 const TEXT_FILTER_TARGET_TITLE = 'title'
 const TEXT_FILTER_TARGET_TITLE_CONTENT = 'title-content'
diff --git a/src-ui/src/app/data/custom-field-query.ts b/src-ui/src/app/data/custom-field-query.ts
new file mode 100644
index 000000000..cbcada40c
--- /dev/null
+++ b/src-ui/src/app/data/custom-field-query.ts
@@ -0,0 +1,227 @@
+import { Subject } from 'rxjs'
+import { CustomFieldDataType } from './custom-field'
+
+export enum CustomFieldQueryLogicalOperator {
+  And = 'AND',
+  Or = 'OR',
+  Not = 'NOT',
+}
+
+export enum CustomFieldQueryOperator {
+  Exact = 'exact',
+  In = 'in',
+  IsNull = 'isnull',
+  Exists = 'exists',
+  Contains = 'contains',
+  IContains = 'icontains',
+  IStartsWith = 'istartswith',
+  IEndsWith = 'iendswith',
+  GreaterThan = 'gt',
+  GreaterThanOrEqual = 'gte',
+  LessThan = 'lt',
+  LessThanOrEqual = 'lte',
+  Range = 'range',
+}
+
+export const CUSTOM_FIELD_QUERY_OPERATOR_LABELS = {
+  [CustomFieldQueryOperator.Exact]: $localize`Equal to`,
+  [CustomFieldQueryOperator.In]: $localize`In`,
+  [CustomFieldQueryOperator.IsNull]: $localize`Is null`,
+  [CustomFieldQueryOperator.Exists]: $localize`Exists`,
+  [CustomFieldQueryOperator.Contains]: $localize`Contains`,
+  [CustomFieldQueryOperator.IContains]: $localize`Contains (case-insensitive)`,
+  [CustomFieldQueryOperator.IStartsWith]: $localize`Starts with (case-insensitive)`,
+  [CustomFieldQueryOperator.IEndsWith]: $localize`Ends with (case-insensitive)`,
+  [CustomFieldQueryOperator.GreaterThan]: $localize`Greater than`,
+  [CustomFieldQueryOperator.GreaterThanOrEqual]: $localize`Greater than or equal to`,
+  [CustomFieldQueryOperator.LessThan]: $localize`Less than`,
+  [CustomFieldQueryOperator.LessThanOrEqual]: $localize`Less than or equal to`,
+  [CustomFieldQueryOperator.Range]: $localize`Range`,
+}
+
+export enum CustomFieldQueryOperatorGroups {
+  Basic = 'basic',
+  String = 'string',
+  Arithmetic = 'arithmetic',
+  Containment = 'containment',
+}
+
+export const CUSTOM_FIELD_QUERY_OPERATORS_BY_GROUP = {
+  [CustomFieldQueryOperatorGroups.Basic]: [
+    CustomFieldQueryOperator.Exact,
+    CustomFieldQueryOperator.In,
+    CustomFieldQueryOperator.IsNull,
+    CustomFieldQueryOperator.Exists,
+  ],
+  [CustomFieldQueryOperatorGroups.String]: [
+    CustomFieldQueryOperator.IContains,
+    CustomFieldQueryOperator.IStartsWith,
+    CustomFieldQueryOperator.IEndsWith,
+  ],
+  [CustomFieldQueryOperatorGroups.Arithmetic]: [
+    CustomFieldQueryOperator.GreaterThan,
+    CustomFieldQueryOperator.GreaterThanOrEqual,
+    CustomFieldQueryOperator.LessThan,
+    CustomFieldQueryOperator.LessThanOrEqual,
+    CustomFieldQueryOperator.Range,
+  ],
+  [CustomFieldQueryOperatorGroups.Containment]: [
+    CustomFieldQueryOperator.Contains,
+  ],
+}
+
+// filters.py > SUPPORTED_EXPR_CATEGORIES
+export const CUSTOM_FIELD_QUERY_OPERATOR_GROUPS_BY_TYPE = {
+  [CustomFieldDataType.String]: [
+    CustomFieldQueryOperatorGroups.Basic,
+    CustomFieldQueryOperatorGroups.String,
+  ],
+  [CustomFieldDataType.Url]: [
+    CustomFieldQueryOperatorGroups.Basic,
+    CustomFieldQueryOperatorGroups.String,
+  ],
+  [CustomFieldDataType.Date]: [
+    CustomFieldQueryOperatorGroups.Basic,
+    CustomFieldQueryOperatorGroups.Arithmetic,
+  ],
+  [CustomFieldDataType.Boolean]: [CustomFieldQueryOperatorGroups.Basic],
+  [CustomFieldDataType.Integer]: [
+    CustomFieldQueryOperatorGroups.Basic,
+    CustomFieldQueryOperatorGroups.Arithmetic,
+  ],
+  [CustomFieldDataType.Float]: [
+    CustomFieldQueryOperatorGroups.Basic,
+    CustomFieldQueryOperatorGroups.Arithmetic,
+  ],
+  [CustomFieldDataType.Monetary]: [
+    CustomFieldQueryOperatorGroups.Basic,
+    CustomFieldQueryOperatorGroups.String,
+  ],
+  [CustomFieldDataType.DocumentLink]: [
+    CustomFieldQueryOperatorGroups.Basic,
+    CustomFieldQueryOperatorGroups.Containment,
+  ],
+  [CustomFieldDataType.Select]: [CustomFieldQueryOperatorGroups.Basic],
+}
+
+export enum CustomFieldQueryElementType {
+  Atom = 'Atom',
+  Expression = 'Expression',
+}
+
+export class CustomFieldQueryElement {
+  public readonly type: CustomFieldQueryElementType
+  public changed: Subject<CustomFieldQueryElement>
+
+  constructor(type: CustomFieldQueryElementType) {
+    this.type = type
+    this.changed = new Subject<CustomFieldQueryElement>()
+  }
+
+  public serialize() {
+    throw new Error('Implemented in subclass')
+  }
+
+  public get isValid(): boolean {
+    throw new Error('Implemented in subclass')
+  }
+
+  protected _operator: string = null
+  set operator(value: string) {
+    this._operator = value
+    this.changed.next(this)
+  }
+  get operator(): string {
+    return this._operator
+  }
+
+  protected _value:
+    | string
+    | CustomFieldQueryAtom[]
+    | CustomFieldQueryExpression[] = null
+  set value(
+    value: string | CustomFieldQueryAtom[] | CustomFieldQueryExpression[]
+  ) {
+    this._value = value
+    this.changed.next(this)
+  }
+  get value(): string | CustomFieldQueryAtom[] | CustomFieldQueryExpression[] {
+    return this._value
+  }
+}
+
+export class CustomFieldQueryAtom extends CustomFieldQueryElement {
+  protected _field: string
+  set field(value: string) {
+    this._field = value
+    if (this.isValid) this.changed.next(this)
+  }
+  get field(): string {
+    return this._field
+  }
+
+  constructor(queryArray: [string, string, string] = [null, null, null]) {
+    super(CustomFieldQueryElementType.Atom)
+    ;[this._field, this._operator, this._value] = queryArray
+  }
+
+  public serialize() {
+    return [this._field, this._operator, this._value.toString()]
+  }
+
+  public get isValid(): boolean {
+    return !!(this._field && this._operator && this._value !== null)
+  }
+}
+
+export class CustomFieldQueryExpression extends CustomFieldQueryElement {
+  constructor(
+    expressionArray: [CustomFieldQueryLogicalOperator, any[]] = [
+      CustomFieldQueryLogicalOperator.And,
+      null,
+    ]
+  ) {
+    super(CustomFieldQueryElementType.Expression)
+    ;[this._operator] = expressionArray
+    let values = expressionArray[1]
+    if (!values) {
+      this._value = []
+    } else if (values?.length > 0 && values[0] instanceof Array) {
+      this._value = values.map((value) => {
+        if (value.length === 3) {
+          const atom = new CustomFieldQueryAtom(value)
+          atom.changed.subscribe(() => {
+            this.changed.next(this)
+          })
+          return atom
+        } else {
+          const expression = new CustomFieldQueryExpression(value)
+          expression.changed.subscribe(() => {
+            this.changed.next(this)
+          })
+          return expression
+        }
+      })
+    } else {
+      this._value = [new CustomFieldQueryExpression(values as any)]
+    }
+  }
+
+  public serialize() {
+    let value
+    if (this._value instanceof Array) {
+      value = this._value.map((atom) => atom.serialize())
+    } else {
+      value = value.serialize()
+    }
+    return [this._operator, value]
+  }
+
+  public get isValid(): boolean {
+    return (
+      this._operator &&
+      this._value.length > 0 &&
+      (this._value as any[]).every((v) => v.isValid)
+    )
+  }
+}
diff --git a/src-ui/src/app/utils/query-params.spec.ts b/src-ui/src/app/utils/query-params.spec.ts
index 67f57423e..201770a78 100644
--- a/src-ui/src/app/utils/query-params.spec.ts
+++ b/src-ui/src/app/utils/query-params.spec.ts
@@ -12,7 +12,7 @@ import { paramsToViewState, transformLegacyFilterRules } from './query-params'
 import { paramsFromViewState } from './query-params'
 import { queryParamsFromFilterRules } from './query-params'
 import { filterRulesFromQueryParams } from './query-params'
-import { CustomFieldQueryLogicalOperator } from '../components/common/custom-fields-query-dropdown/custom-fields-query-dropdown.component'
+import { CustomFieldQueryLogicalOperator } from '../data/custom-field-query'
 
 const tags__id__all = '9'
 const filterRules: FilterRule[] = [
diff --git a/src-ui/src/app/utils/query-params.ts b/src-ui/src/app/utils/query-params.ts
index ac54efd15..68009fec1 100644
--- a/src-ui/src/app/utils/query-params.ts
+++ b/src-ui/src/app/utils/query-params.ts
@@ -8,7 +8,10 @@ import {
   FILTER_HAS_CUSTOM_FIELDS_ALL,
 } from '../data/filter-rule-type'
 import { ListViewState } from '../services/document-list-view.service'
-import { CustomFieldQueryLogicalOperator } from '../components/common/custom-fields-query-dropdown/custom-fields-query-dropdown.component'
+import {
+  CustomFieldQueryLogicalOperator,
+  CustomFieldQueryOperator,
+} from '../data/custom-field-query'
 
 const SORT_FIELD_PARAMETER = 'sort'
 const SORT_REVERSE_PARAMETER = 'reverse'
@@ -71,7 +74,13 @@ export function transformLegacyFilterRules(
     const valueRules = allRules.length ? allRules : anyRules
     const customFieldQueryExpression = [
       customFieldQueryLogicalOperator,
-      [...valueRules.map((rule) => [parseInt(rule.value), 'exists', true])],
+      [
+        ...valueRules.map((rule) => [
+          parseInt(rule.value),
+          CustomFieldQueryOperator.Exists,
+          true,
+        ]),
+      ],
     ]
     filterRules.push({
       rule_type: FILTER_CUSTOM_FIELDS_LOOKUP,