diff --git a/backend/src/.jest-cache/haste-map-60cab15b743c6776f41d29bcac696b99-0ca4a1d6e3dfec1d63b61b0119442391-1908b04cd11e739233ee8977de00dc57 b/backend/src/.jest-cache/haste-map-60cab15b743c6776f41d29bcac696b99-0ca4a1d6e3dfec1d63b61b0119442391-1908b04cd11e739233ee8977de00dc57
index 6f815d4..66badb7 100644
Binary files a/backend/src/.jest-cache/haste-map-60cab15b743c6776f41d29bcac696b99-0ca4a1d6e3dfec1d63b61b0119442391-1908b04cd11e739233ee8977de00dc57 and b/backend/src/.jest-cache/haste-map-60cab15b743c6776f41d29bcac696b99-0ca4a1d6e3dfec1d63b61b0119442391-1908b04cd11e739233ee8977de00dc57 differ
diff --git a/frontend/app/(admin)/admin/access-control/users/page.tsx b/frontend/app/(admin)/admin/access-control/users/page.tsx
index a3f5a3f..d9b7259 100644
--- a/frontend/app/(admin)/admin/access-control/users/page.tsx
+++ b/frontend/app/(admin)/admin/access-control/users/page.tsx
@@ -113,7 +113,7 @@ export default function UsersPage() {
         return (
           <div className="flex flex-wrap gap-1">
             {roles.map((r) => (
-              <Badge key={r.roleId} variant="outline" className="text-xs">
+              <Badge key={r.publicId} variant="outline" className="text-xs">
                 {r.roleName}
               </Badge>
             ))}
diff --git a/frontend/app/(admin)/admin/doc-control/workflows/page.tsx b/frontend/app/(admin)/admin/doc-control/workflows/page.tsx
index 49118f7..6c9347a 100644
--- a/frontend/app/(admin)/admin/doc-control/workflows/page.tsx
+++ b/frontend/app/(admin)/admin/doc-control/workflows/page.tsx
@@ -42,7 +42,7 @@ export default function WorkflowsPage() {
       ) : (
         <div className="grid gap-4">
           {workflowList.map((workflow: Workflow) => (
-            <Card key={workflow.workflowId} className="p-6">
+            <Card key={workflow.publicId} className="p-6">
               <div className="flex justify-between items-start">
                 <div className="flex-1">
                   <div className="flex items-center gap-3 mb-2">
@@ -64,7 +64,7 @@ export default function WorkflowsPage() {
                 </div>
 
                 <div className="flex gap-2">
-                  <Link href={`/admin/doc-control/workflows/${workflow.workflowId}/edit`}>
+                  <Link href={`/admin/doc-control/workflows/${workflow.publicId}/edit`}>
                     <Button variant="outline" size="sm">
                       <Edit className="mr-2 h-4 w-4" />
                       Edit
diff --git a/frontend/app/(admin)/admin/monitoring/audit-logs/page.tsx b/frontend/app/(admin)/admin/monitoring/audit-logs/page.tsx
index e3cb473..1352c1c 100644
--- a/frontend/app/(admin)/admin/monitoring/audit-logs/page.tsx
+++ b/frontend/app/(admin)/admin/monitoring/audit-logs/page.tsx
@@ -26,12 +26,12 @@ export default function AuditLogsPage() {
             <div className="text-center text-muted-foreground py-10">No logs found</div>
           ) : (
             logs.map((log: import('@/lib/services/audit-log.service').AuditLog) => (
-              <Card key={log.auditId} className="p-4">
+              <Card key={log.publicId} className="p-4">
                 <div className="flex items-start justify-between">
                   <div className="flex-1">
                     <div className="flex items-center gap-3 mb-2">
                       <span className="font-medium text-sm">
-                        {log.user?.fullName || log.user?.username || `User #${log.userId || 'System'}`}
+                        {log.user?.fullName || log.user?.username || `User #${log.user?.userId || 'System'}`}
                       </span>
                       <Badge
                         variant={log.severity === 'ERROR' ? 'destructive' : 'outline'}
diff --git a/frontend/components/admin/organization-dialog.tsx b/frontend/components/admin/organization-dialog.tsx
index 412b5d0..4a1a7bf 100644
--- a/frontend/components/admin/organization-dialog.tsx
+++ b/frontend/components/admin/organization-dialog.tsx
@@ -64,7 +64,7 @@ export function OrganizationDialog({ open, onOpenChange, organization }: Organiz
       reset({
         organizationCode: organization.organizationCode,
         organizationName: organization.organizationName,
-        roleId: organization.roleId?.toString() || '',
+        roleId: organization.publicId?.toString() || '',
         isActive: organization.isActive,
       });
     } else {
@@ -80,7 +80,7 @@ export function OrganizationDialog({ open, onOpenChange, organization }: Organiz
   const onSubmit = (data: OrganizationFormData) => {
     const submitData = {
       ...data,
-      roleId: data.roleId ? Number(data.roleId) : undefined,
+      roleId: data.roleId ? String(data.roleId) : undefined,
     };
 
     if (organization) {
diff --git a/frontend/components/admin/security/rbac-matrix.tsx b/frontend/components/admin/security/rbac-matrix.tsx
index 2cf2a29..1be56d8 100644
--- a/frontend/components/admin/security/rbac-matrix.tsx
+++ b/frontend/components/admin/security/rbac-matrix.tsx
@@ -137,7 +137,7 @@ export function RbacMatrix() {
             <TableRow>
               <TableHead className="w-[300px]">Permission</TableHead>
               {roleList.map((role) => (
-                <TableHead key={role.roleId} className="text-center min-w-[100px]">
+                <TableHead key={role.publicId} className="text-center min-w-[100px]">
                   {role.roleName}
                 </TableHead>
               ))}
@@ -153,14 +153,14 @@ export function RbacMatrix() {
                 {roleList.map((role) => {
                   // Assume role.permissions is populated
                   const currentRolePerms = role.permissions?.map((p) => p.permissionId) || [];
-                  const activePerms = pendingChanges[role.roleId] || currentRolePerms;
+                  const activePerms = pendingChanges[role.publicId] || currentRolePerms;
                   const isChecked = activePerms.includes(perm.permissionId);
 
                   return (
-                    <TableCell key={`${role.roleId}-${perm.permissionId}`} className="text-center">
+                    <TableCell key={`${role.publicId}-${perm.permissionId}`} className="text-center">
                       <Checkbox
                         checked={isChecked}
-                        onCheckedChange={() => handleToggle(role.roleId, perm.permissionId, currentRolePerms)}
+                        onCheckedChange={() => handleToggle(role.publicId, perm.permissionId, currentRolePerms)}
                       />
                     </TableCell>
                   );
diff --git a/frontend/components/admin/user-dialog.tsx b/frontend/components/admin/user-dialog.tsx
index a3427d3..22aba33 100644
--- a/frontend/components/admin/user-dialog.tsx
+++ b/frontend/components/admin/user-dialog.tsx
@@ -108,7 +108,7 @@ export function UserDialog({ open, onOpenChange, user }: UserDialogProps) {
         isActive: user.isActive,
         lineId: user.lineId || '',
         primaryOrganizationId: user.primaryOrganizationId?.toString() || ALL_ORGANIZATIONS_VALUE,
-        roleIds: user.roles?.map((r: { roleId: number }) => r.roleId) || [],
+        roleIds: user.roles?.map((r: { publicId: string }) => r.publicId) || [],
         password: '',
         confirmPassword: '',
       });
@@ -297,26 +297,26 @@ export function UserDialog({ open, onOpenChange, user }: UserDialogProps) {
                 <p className="text-sm text-muted-foreground">Loading roles...</p>
               )}
               {Array.isArray(roles) &&
-                roles.map((role: { roleId: number; roleName: string; description?: string }) => (
-                  <div key={role.roleId} className="flex items-start space-x-2">
+                roles.map((role: { publicId: string; roleName: string; description?: string }) => (
+                  <div key={role.publicId} className="flex items-start space-x-2">
                     <Checkbox
-                      id={`role-${role.roleId}`}
-                      checked={selectedRoleIds.includes(role.roleId)}
+                      id={`role-${role.publicId}`}
+                      checked={selectedRoleIds.includes(role.publicId)}
                       onCheckedChange={(checked) => {
                         const current = selectedRoleIds;
                         if (checked) {
-                          setValue('roleIds', [...current, role.roleId]);
+                          setValue('roleIds', [...current, role.publicId]);
                         } else {
                           setValue(
                             'roleIds',
-                            current.filter((id) => id !== role.roleId)
+                            current.filter((id) => id !== role.publicId)
                           );
                         }
                       }}
                     />
                     <div className="grid gap-1.5 leading-none">
                       <label
-                        htmlFor={`role-${role.roleId}`}
+                        htmlFor={`role-${role.publicId}`}
                         className="text-sm font-medium leading-none cursor-pointer"
                       >
                         {role.roleName}
diff --git a/frontend/components/correspondences/tag-manager.tsx b/frontend/components/correspondences/tag-manager.tsx
index 8bc6d6a..9340880 100644
--- a/frontend/components/correspondences/tag-manager.tsx
+++ b/frontend/components/correspondences/tag-manager.tsx
@@ -30,14 +30,14 @@ export function TagManager({ uuid, canEdit }: TagManagerProps) {
 
   const assigned: Tag[] = Array.isArray(assignedRaw) ? (assignedRaw as Tag[]) : [];
   const allTags: Tag[] = Array.isArray(allTagsRaw) ? (allTagsRaw as Tag[]) : [];
-  const assignedIds = new Set(assigned.map((t) => t.id));
-  const available = allTags.filter((t) => !assignedIds.has(t.id));
+  const assignedIds = new Set(assigned.map((t) => t.publicId));
+  const available = allTags.filter((t) => !assignedIds.has(t.publicId));
 
-  const handleAdd = (tagId: number) => {
+  const handleAdd = (tagId: number | string) => {
     addMutation.mutate({ uuid, tagId });
   };
 
-  const handleRemove = (tagId: number) => {
+  const handleRemove = (tagId: number | string) => {
     removeMutation.mutate({ uuid, tagId });
   };
 
@@ -71,7 +71,7 @@ export function TagManager({ uuid, canEdit }: TagManagerProps) {
           <div className="flex flex-wrap gap-1.5">
             {assigned.map((tag) => (
               <span
-                key={tag.id}
+                key={tag.publicId}
                 className="inline-flex items-center gap-1 px-2 py-0.5 rounded-full text-xs font-medium border"
                 style={{
                   backgroundColor: `${getTagColor(tag.colorCode)}22`,
@@ -86,7 +86,7 @@ export function TagManager({ uuid, canEdit }: TagManagerProps) {
                 {tag.tagName}
                 {canEdit && (
                   <button
-                    onClick={() => handleRemove(tag.id)}
+                    onClick={() => handleRemove(tag.publicId)}
                     disabled={removeMutation.isPending}
                     className="ml-0.5 opacity-60 hover:opacity-100 transition-opacity"
                   >
@@ -110,9 +110,9 @@ export function TagManager({ uuid, canEdit }: TagManagerProps) {
                   ) : (
                     available.map((tag) => (
                       <button
-                        key={tag.id}
+                        key={tag.publicId}
                         className="w-full flex items-center gap-2 p-2 text-xs hover:bg-muted/60 transition-colors text-left"
-                        onClick={() => { handleAdd(tag.id); setIsOpen(false); }}
+                        onClick={() => { handleAdd(tag.publicId); setIsOpen(false); }}
                         disabled={addMutation.isPending}
                       >
                         <span
diff --git a/frontend/components/drawings/revision-history.tsx b/frontend/components/drawings/revision-history.tsx
index 20313fc..0807819 100644
--- a/frontend/components/drawings/revision-history.tsx
+++ b/frontend/components/drawings/revision-history.tsx
@@ -14,7 +14,7 @@ export function RevisionHistory({ revisions }: { revisions: DrawingRevision[] })
 
       <div className="space-y-3">
         {revisions.map((rev) => (
-          <div key={rev.revisionId} className="flex items-center justify-between p-3 bg-muted/30 rounded-lg border">
+          <div key={rev.publicId} className="flex items-center justify-between p-3 bg-muted/30 rounded-lg border">
             <div className="flex-1">
               <div className="flex items-center gap-3 mb-1">
                 <Badge variant={rev.isCurrent ? 'default' : 'outline'}>Rev. {rev.revisionNumber}</Badge>
diff --git a/frontend/components/numbering/template-editor.tsx b/frontend/components/numbering/template-editor.tsx
index 2f0a0d2..814e630 100644
--- a/frontend/components/numbering/template-editor.tsx
+++ b/frontend/components/numbering/template-editor.tsx
@@ -120,7 +120,7 @@ export function TemplateEditor({
                 <SelectItem value="__default__">Default (All Types)</SelectItem>
                 {correspondenceTypes.map((type) => {
                   return (
-                    <SelectItem key={type.id} value={type.id.toString()}>
+                    <SelectItem key={type.publicId} value={type.publicId.toString()}>
                       {type.typeCode} - {type.typeName}
                     </SelectItem>
                   );
@@ -142,7 +142,7 @@ export function TemplateEditor({
                 <SelectContent>
                   <SelectItem value="0">All Disciplines</SelectItem>
                   {disciplines.map((d) => (
-                    <SelectItem key={d.id} value={d.id.toString()}>
+                    <SelectItem key={d.publicId} value={d.publicId.toString()}>
                       {d.disciplineCode} - {d.codeNameEn || d.codeNameTh}
                     </SelectItem>
                   ))}
diff --git a/frontend/components/numbering/template-tester.tsx b/frontend/components/numbering/template-tester.tsx
index e92512d..056ff26 100644
--- a/frontend/components/numbering/template-tester.tsx
+++ b/frontend/components/numbering/template-tester.tsx
@@ -158,7 +158,7 @@ export function TemplateTester({ open, onOpenChange, template }: TemplateTesterP
                       <SelectContent>
                         <SelectItem value="0">Default (All Types)</SelectItem>
                         {(correspondenceTypes as CorrespondenceType[])?.map((type) => (
-                          <SelectItem key={type.id} value={type.id.toString()}>
+                          <SelectItem key={type.publicId} value={type.publicId.toString()}>
                             {type.typeCode} - {type.typeName}
                           </SelectItem>
                         ))}
@@ -179,7 +179,7 @@ export function TemplateTester({ open, onOpenChange, template }: TemplateTesterP
                       <SelectContent>
                         <SelectItem value="0">None</SelectItem>
                         {(disciplines as Discipline[])?.map((disc) => (
-                          <SelectItem key={disc.id} value={disc.id.toString()}>
+                          <SelectItem key={disc.publicId} value={disc.publicId.toString()}>
                             {disc.disciplineCode}
                           </SelectItem>
                         ))}
diff --git a/frontend/components/rfas/form.tsx b/frontend/components/rfas/form.tsx
index fa7b291..95436c0 100644
--- a/frontend/components/rfas/form.tsx
+++ b/frontend/components/rfas/form.tsx
@@ -26,7 +26,7 @@ const rfaSchema = z.object({
   projectId: z.string().min(1, 'Project is required'), // ADR-019: UUID
   contractId: z.string().min(1, 'Contract is required'),
   disciplineId: z.number({ message: 'Discipline is required' }).min(1, 'Discipline is required'),
-  rfaTypeId: z.number().min(1, 'Type is required'),
+  rfaTypeId: z.string().min(1, 'Type is required'), // ADR-019: UUID
   subject: z.string().min(5, 'Subject must be at least 5 characters'),
   description: z.string().optional(),
   body: z.string().optional(),
@@ -53,14 +53,16 @@ type ContractOption = {
 };
 
 type DisciplineOption = {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT
   disciplineCode: string;
   codeNameEn?: string;
   codeNameTh?: string;
 };
 
 type RfaTypeOption = {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT
   typeCode?: string;
   typeName?: string;
   typeNameEn?: string;
@@ -68,7 +70,7 @@ type RfaTypeOption = {
 };
 
 type CorrespondenceTypeOption = {
-  id: number;
+  publicId: string; // ADR-019: public identifier
   typeCode?: string;
   typeName?: string;
 };
@@ -164,7 +166,7 @@ export function RFAForm() {
       projectId: '',
       contractId: '',
       disciplineId: 0,
-      rfaTypeId: 0,
+      rfaTypeId: '',
       subject: '',
       description: '',
       body: '',
@@ -185,13 +187,13 @@ export function RFAForm() {
 
   const selectedContractId = watch('contractId');
   const { data: disciplinesData, isLoading: isLoadingDisciplines } = useDisciplines(selectedContractId);
-  const disciplines = dedupeByKey(extractArrayData<DisciplineOption>(disciplinesData), (discipline) => discipline.id);
+  const disciplines = dedupeByKey(extractArrayData<DisciplineOption>(disciplinesData), (discipline) => discipline.publicId);
   const { data: rfaTypesData, isLoading: isLoadingRfaTypes } = useRfaTypes(selectedContractId);
-  const rfaTypes = dedupeByKey(extractArrayData<RfaTypeOption>(rfaTypesData), (rfaType) => rfaType.id);
+  const rfaTypes = dedupeByKey(extractArrayData<RfaTypeOption>(rfaTypesData), (rfaType) => rfaType.publicId);
   const [shopDrawingSearch, setShopDrawingSearch] = useState('');
   const [shopDrawingPage, setShopDrawingPage] = useState(1);
   const { data: shopDrawingsData, isLoading: isLoadingShopDrawings } = useDrawings('SHOP', {
-    projectPublicId: selectedProjectId || '',
+    projectUuid: selectedProjectId || '',
     search: shopDrawingSearch,
     page: shopDrawingPage,
     limit: 10,
@@ -204,7 +206,7 @@ export function RFAForm() {
   const [asBuiltDrawingSearch, setAsBuiltDrawingSearch] = useState('');
   const [asBuiltDrawingPage, setAsBuiltDrawingPage] = useState(1);
   const { data: asBuiltDrawingsData, isLoading: isLoadingAsBuiltDrawings } = useDrawings('AS_BUILT', {
-    projectPublicId: selectedProjectId || '',
+    projectUuid: selectedProjectId || '',
     search: asBuiltDrawingSearch,
     page: asBuiltDrawingPage,
     limit: 10,
@@ -220,7 +222,7 @@ export function RFAForm() {
   const toOrganizationId = watch('toOrganizationId');
   const selectedShopDrawingRevisionIds = watch('shopDrawingRevisionIds') ?? [];
   const selectedAsBuiltDrawingRevisionIds = watch('asBuiltDrawingRevisionIds') ?? [];
-  const selectedRfaType = rfaTypes.find((rfaType) => rfaType.id === rfaTypeId);
+  const selectedRfaType = rfaTypes.find((rfaType) => rfaType.publicId === rfaTypeId);
   const selectedRfaTypeCode = selectedRfaType?.typeCode?.toUpperCase();
   const requiresShopDrawings = selectedRfaTypeCode === 'DDW' || selectedRfaTypeCode === 'SDW';
   const requiresAsBuiltDrawings = selectedRfaTypeCode === 'ADW';
@@ -254,7 +256,7 @@ export function RFAForm() {
   const [preview, setPreview] = useState<{ number: string; isDefaultTemplate: boolean } | null>(null);
 
   useEffect(() => {
-    if (!selectedProjectId || !rfaCorrespondenceType?.id || !rfaTypeId || !disciplineId || !toOrganizationId) {
+    if (!selectedProjectId || !rfaCorrespondenceType?.publicId || !rfaTypeId || !disciplineId || !toOrganizationId) {
       setPreview(null);
       return;
     }
@@ -263,7 +265,7 @@ export function RFAForm() {
       try {
         const res = await correspondenceService.previewNumber({
           projectId: selectedProjectId,
-          typeId: rfaCorrespondenceType.id,
+          typeId: rfaCorrespondenceType.publicId,
           disciplineId,
           recipients: [{ organizationId: toOrganizationId, type: 'TO' }],
           subject: watch('subject') || 'Preview Subject',
@@ -276,7 +278,7 @@ export function RFAForm() {
 
     const timer = setTimeout(fetchPreview, 500);
     return () => clearTimeout(timer);
-  }, [rfaTypeId, disciplineId, toOrganizationId, selectedProjectId, rfaCorrespondenceType?.id, watch]);
+  }, [rfaTypeId, disciplineId, toOrganizationId, selectedProjectId, rfaCorrespondenceType?.publicId, watch]);
 
   const onSubmit = (data: RFAFormData) => {
     if (requiresShopDrawings && data.shopDrawingRevisionIds?.length === 0) {
@@ -365,7 +367,7 @@ export function RFAForm() {
                 setValue('projectId', val);
                 setValue('contractId', '');
                 setValue('disciplineId', 0);
-                setValue('rfaTypeId', 0);
+                setValue('rfaTypeId', '');
                 setValue('shopDrawingRevisionIds', []);
                 setValue('asBuiltDrawingRevisionIds', []);
               }}
@@ -441,7 +443,7 @@ export function RFAForm() {
                 </SelectTrigger>
                 <SelectContent>
                   {disciplines.map((d) => (
-                    <SelectItem key={d.id} value={String(d.id)}>
+                    <SelectItem key={d.publicId} value={String(d.publicId)}>
                       {`${d.codeNameEn || d.codeNameTh || d.disciplineCode} (${d.disciplineCode})`}
                     </SelectItem>
                   ))}
@@ -460,9 +462,9 @@ export function RFAForm() {
             <div>
               <Label>RFA Type *</Label>
               <Select
-                value={rfaTypeId > 0 ? String(rfaTypeId) : undefined}
+                value={rfaTypeId || undefined}
                 onValueChange={(val) => {
-                  setValue('rfaTypeId', Number(val));
+                  setValue('rfaTypeId', val);
                   setValue('shopDrawingRevisionIds', []);
                   setValue('asBuiltDrawingRevisionIds', []);
                 }}
@@ -473,7 +475,7 @@ export function RFAForm() {
                 </SelectTrigger>
                 <SelectContent>
                   {rfaTypes.map((rfaType) => (
-                    <SelectItem key={rfaType.id} value={String(rfaType.id)}>
+                    <SelectItem key={rfaType.publicId} value={String(rfaType.publicId)}>
                       {`${rfaType.typeCode || 'RFA'} - ${rfaType.typeName || rfaType.typeNameEn || rfaType.typeNameTh || 'Unnamed Type'}`}
                     </SelectItem>
                   ))}
diff --git a/frontend/hooks/use-correspondence.ts b/frontend/hooks/use-correspondence.ts
index cd4adff..f6e8d3c 100644
--- a/frontend/hooks/use-correspondence.ts
+++ b/frontend/hooks/use-correspondence.ts
@@ -141,7 +141,7 @@ export function useAddTag() {
   const queryClient = useQueryClient();
 
   return useMutation({
-    mutationFn: ({ uuid, tagId }: { uuid: string; tagId: number }) =>
+    mutationFn: ({ uuid, tagId }: { uuid: string; tagId: number | string }) =>
       correspondenceService.addTag(uuid, tagId),
     onSuccess: (_, { uuid }) => {
       toast.success('Tag added');
@@ -159,7 +159,7 @@ export function useRemoveTag() {
   const queryClient = useQueryClient();
 
   return useMutation({
-    mutationFn: ({ uuid, tagId }: { uuid: string; tagId: number }) =>
+    mutationFn: ({ uuid, tagId }: { uuid: string; tagId: number | string }) =>
       correspondenceService.removeTag(uuid, tagId),
     onSuccess: (_, { uuid }) => {
       toast.success('Tag removed');
diff --git a/frontend/types/admin.ts b/frontend/types/admin.ts
index 822000c..ca2f146 100644
--- a/frontend/types/admin.ts
+++ b/frontend/types/admin.ts
@@ -1,11 +1,13 @@
 export interface Role {
-  roleId: number;
+  publicId: string; // ADR-019: public identifier
+  roleId?: number; // Internal INT (excluded from API)
   roleName: string;
   description: string;
 }
 
 export interface User {
-  userId: number;
+  publicId: string; // ADR-019: public identifier
+  userId?: number; // Internal INT (excluded from API)
   username: string;
   email: string;
   firstName: string;
@@ -25,7 +27,8 @@ export interface CreateUserDto {
 }
 
 export interface Organization {
-  orgId: number;
+  publicId: string; // ADR-019: public identifier
+  orgId?: number; // Internal INT (excluded from API)
   orgCode: string;
   orgName: string;
   orgNameTh?: string;
@@ -33,7 +36,8 @@ export interface Organization {
 }
 
 export interface AuditLog {
-  auditLogId: number;
+  publicId: string; // ADR-019: public identifier
+  auditLogId?: number; // Internal INT (excluded from API)
   userName: string;
   action: string;
   entityType: string;
diff --git a/frontend/types/dto/correspondence/create-correspondence.dto.ts b/frontend/types/dto/correspondence/create-correspondence.dto.ts
index 1d10821..55ee4f9 100644
--- a/frontend/types/dto/correspondence/create-correspondence.dto.ts
+++ b/frontend/types/dto/correspondence/create-correspondence.dto.ts
@@ -4,14 +4,14 @@ export interface CreateCorrespondenceDto {
   /** ID or UUID ของโครงการ */
   projectId: number | string;
 
-  /** ID ของประเภทเอกสาร (เช่น RFA, LETTER) */
-  typeId: number;
+  /** ID ของประเภทเอกสาร (เช่น RFA, LETTER) - ADR-019: Accept UUID */
+  typeId: number | string;
 
-  /** [Req 6B] สาขางาน (เช่น GEN, STR) */
-  disciplineId?: number;
+  /** [Req 6B] สาขางาน (เช่น GEN, STR) - ADR-019: Accept UUID */
+  disciplineId?: number | string;
 
-  /** [Req 6B] ประเภทย่อย (เช่น MAT, SHP สำหรับ Transmittal/RFA) */
-  subTypeId?: number;
+  /** [Req 6B] ประเภทย่อย (เช่น MAT, SHP สำหรับ Transmittal/RFA) - ADR-019: Accept UUID */
+  subTypeId?: number | string;
 
   /** หัวข้อเอกสาร */
   subject: string;
diff --git a/frontend/types/dto/correspondence/search-correspondence.dto.ts b/frontend/types/dto/correspondence/search-correspondence.dto.ts
index 251d5a0..955f831 100644
--- a/frontend/types/dto/correspondence/search-correspondence.dto.ts
+++ b/frontend/types/dto/correspondence/search-correspondence.dto.ts
@@ -2,9 +2,9 @@
 
 export interface SearchCorrespondenceDto {
   search?: string; // ค้นหาจาก Title หรือ Number
-  typeId?: number; // กรองตามประเภทเอกสาร
-  projectId?: number; // กรองตามโครงการ
-  statusId?: number; // กรองตามสถานะ (จาก Revision ปัจจุบัน)
+  typeId?: number | string; // ADR-019: Accept UUID - กรองตามประเภทเอกสาร
+  projectId?: number | string; // ADR-019: Accept UUID - กรองตามโครงการ
+  statusId?: number | string; // ADR-019: Accept UUID - กรองตามสถานะ (จาก Revision ปัจจุบัน)
   status?: string; // กรองตามสถานะ code string (เช่น DRAFT, IN_REVIEW)
   revisionStatus?: 'CURRENT' | 'ALL' | 'OLD'; // กรองตามสถานะ Revision
 
diff --git a/frontend/types/dto/drawing/asbuilt-drawing.dto.ts b/frontend/types/dto/drawing/asbuilt-drawing.dto.ts
index b595e6a..9ecc7e8 100644
--- a/frontend/types/dto/drawing/asbuilt-drawing.dto.ts
+++ b/frontend/types/dto/drawing/asbuilt-drawing.dto.ts
@@ -2,10 +2,10 @@
 
 // --- Create New As Built Drawing ---
 export interface CreateAsBuiltDrawingDto {
-  projectId: number;
+  projectId: number | string; // ADR-019: Accept UUID
   drawingNumber: string;
-  mainCategoryId: number;
-  subCategoryId: number;
+  mainCategoryId: number | string; // ADR-019: Accept UUID
+  subCategoryId: number | string; // ADR-019: Accept UUID
 
   // First Revision Data
   revisionLabel?: string;
@@ -14,8 +14,8 @@ export interface CreateAsBuiltDrawingDto {
   revisionDate?: string; // ISO Date String
   description?: string;
 
-  shopDrawingRevisionIds?: number[]; // Reference to Shop Drawing Revisions
-  attachmentIds?: number[];
+  shopDrawingRevisionIds?: (number | string)[]; // ADR-019: Accept UUID - Reference to Shop Drawing Revisions
+  attachmentIds?: (number | string)[]; // ADR-019: Accept UUID
 }
 
 // --- Create New Revision ---
@@ -26,8 +26,8 @@ export interface CreateAsBuiltDrawingRevisionDto {
   revisionDate?: string;
   description?: string;
 
-  shopDrawingRevisionIds?: number[];
-  attachmentIds?: number[];
+  shopDrawingRevisionIds?: (number | string)[]; // ADR-019: Accept UUID
+  attachmentIds?: (number | string)[]; // ADR-019: Accept UUID
 }
 
 // --- Search ---
diff --git a/frontend/types/dto/drawing/contract-drawing.dto.ts b/frontend/types/dto/drawing/contract-drawing.dto.ts
index 5a88160..3ca1b22 100644
--- a/frontend/types/dto/drawing/contract-drawing.dto.ts
+++ b/frontend/types/dto/drawing/contract-drawing.dto.ts
@@ -2,8 +2,8 @@
 
 // --- Create ---
 export interface CreateContractDrawingDto {
-  /** ID ของโครงการ */
-  projectId: number;
+  /** ID ของโครงการ - ADR-019: Accept UUID */
+  projectId: number | string;
 
   /** เลขที่แบบสัญญา */
   contractDrawingNo: string;
@@ -11,17 +11,17 @@ export interface CreateContractDrawingDto {
   /** ชื่อแบบ */
   title: string;
 
-  /** ID หมวดหมู่ย่อย (Mapping) */
-  mapCatId?: number;
+  /** ID หมวดหมู่ย่อย (Mapping) - ADR-019: Accept UUID */
+  mapCatId?: number | string;
 
-  /** ID เล่มของแบบ */
-  volumeId?: number;
+  /** ID เล่มของแบบ - ADR-019: Accept UUID */
+  volumeId?: number | string;
 
   /** เลขหน้าในเล่ม */
   volumePage?: number;
 
-  /** รายการ ID ของไฟล์แนบ (PDF/DWG) */
-  attachmentIds?: number[];
+  /** รายการ ID ของไฟล์แนบ (PDF/DWG) - ADR-019: Accept UUID */
+  attachmentIds?: (number | string)[];
 }
 
 // --- Update (Partial) ---
@@ -32,8 +32,8 @@ export interface SearchContractDrawingDto {
   /** จำเป็นต้องระบุ Project UUID เสมอ */
   projectUuid: string;
 
-  volumeId?: number;
-  mapCatId?: number;
+  volumeId?: number | string; // ADR-019: Accept UUID
+  mapCatId?: number | string; // ADR-019: Accept UUID
   search?: string; // ค้นหาจาก Title หรือ Number
 
   page?: number; // Default: 1
diff --git a/frontend/types/dto/drawing/shop-drawing.dto.ts b/frontend/types/dto/drawing/shop-drawing.dto.ts
index cbc470c..0e5ed14 100644
--- a/frontend/types/dto/drawing/shop-drawing.dto.ts
+++ b/frontend/types/dto/drawing/shop-drawing.dto.ts
@@ -2,19 +2,19 @@
 
 // --- Create New Shop Drawing ---
 export interface CreateShopDrawingDto {
-  projectId: number;
+  projectId: number | string; // ADR-019: Accept UUID
   drawingNumber: string;
   title: string;
-  mainCategoryId: number;
-  subCategoryId: number;
+  mainCategoryId: number | string; // ADR-019: Accept UUID
+  subCategoryId: number | string; // ADR-019: Accept UUID
 
   // First Revision Data (Optional)
   revisionLabel?: string;
   revisionDate?: string; // ISO Date String
   description?: string;
   legacyDrawingNumber?: string; // Legacy number for the first revision
-  contractDrawingIds?: number[]; // อ้างอิงแบบสัญญา
-  attachmentIds?: number[];
+  contractDrawingIds?: (number | string)[]; // ADR-019: Accept UUID - อ้างอิงแบบสัญญา
+  attachmentIds?: (number | string)[]; // ADR-019: Accept UUID
 }
 
 // --- Create New Revision ---
@@ -24,15 +24,15 @@ export interface CreateShopDrawingRevisionDto {
   legacyDrawingNumber?: string;
   revisionDate?: string;
   description?: string;
-  contractDrawingIds?: number[];
-  attachmentIds?: number[];
+  contractDrawingIds?: (number | string)[]; // ADR-019: Accept UUID
+  attachmentIds?: (number | string)[]; // ADR-019: Accept UUID
 }
 
 // --- Search ---
 export interface SearchShopDrawingDto {
   projectUuid: string;
-  mainCategoryId?: number;
-  subCategoryId?: number;
+  mainCategoryId?: number | string; // ADR-019: Accept UUID
+  subCategoryId?: number | string; // ADR-019: Accept UUID
   search?: string;
 
   page?: number; // Default: 1
diff --git a/frontend/types/dto/master/discipline.dto.ts b/frontend/types/dto/master/discipline.dto.ts
index f80750c..bb2f806 100644
--- a/frontend/types/dto/master/discipline.dto.ts
+++ b/frontend/types/dto/master/discipline.dto.ts
@@ -1,7 +1,7 @@
 // File: src/types/dto/master/discipline.dto.ts
 
 export interface CreateDisciplineDto {
-  contractId: number;
+  contractId: number | string; // ADR-019: Accept UUID
 
   /** รหัสสาขา (เช่น 'STR', 'ARC') */
   disciplineCode: string;
diff --git a/frontend/types/dto/master/tag.dto.ts b/frontend/types/dto/master/tag.dto.ts
index 98f9732..5b50c2f 100644
--- a/frontend/types/dto/master/tag.dto.ts
+++ b/frontend/types/dto/master/tag.dto.ts
@@ -1,8 +1,8 @@
 // File: src/types/dto/master/tag.dto.ts
 
 export interface CreateTagDto {
-  /** ID โครงการ (NULL = Global) */
-  projectId?: number | null;
+  /** ID โครงการ (NULL = Global) - ADR-019: Accept UUID */
+  projectId?: number | string | null;
 
   /** ชื่อ Tag (เช่น 'URGENT') */
   tagName: string;
@@ -17,8 +17,8 @@ export interface CreateTagDto {
 export type UpdateTagDto = Partial<CreateTagDto>;
 
 export interface SearchTagDto {
-  /** ID โครงการ (ใช้กรอง Tag ของแต่ละโปรเจกต์) */
-  projectId?: number;
+  /** ID โครงการ (ใช้กรอง Tag ของแต่ละโปรเจกต์) - ADR-019: Accept UUID */
+  projectId?: number | string;
 
   /** คำค้นหา (ชื่อ Tag หรือ คำอธิบาย) */
   search?: string;
diff --git a/frontend/types/dto/numbering.dto.ts b/frontend/types/dto/numbering.dto.ts
index 47317b2..85b5fc6 100644
--- a/frontend/types/dto/numbering.dto.ts
+++ b/frontend/types/dto/numbering.dto.ts
@@ -8,7 +8,8 @@ export interface AuditErrorRecord {
 }
 
 export interface NumberingAuditLog {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   documentNumber: string;
   operation: string;
   status: string;
@@ -22,13 +23,13 @@ export interface NumberingMetrics {
 }
 
 export interface ManualOverrideDto {
-  projectId: number;
-  originatorOrganizationId: number;
-  recipientOrganizationId: number;
-  correspondenceTypeId: number;
-  subTypeId?: number;
-  rfaTypeId?: number;
-  disciplineId?: number;
+  projectId: number | string; // ADR-019: Accept UUID
+  originatorOrganizationId: number | string; // ADR-019: Accept UUID
+  recipientOrganizationId: number | string; // ADR-019: Accept UUID
+  correspondenceTypeId: number | string; // ADR-019: Accept UUID
+  subTypeId?: number | string; // ADR-019: Accept UUID
+  rfaTypeId?: number | string; // ADR-019: Accept UUID
+  disciplineId?: number | string; // ADR-019: Accept UUID
   resetScope: string;
   newLastNumber: number;
   reason: string;
@@ -38,16 +39,16 @@ export interface VoidReplaceDto {
   documentNumber: string;
   reason: string;
   replace: boolean;
-  projectId: number;
+  projectId: number | string; // ADR-019: Accept UUID
 }
 
 export interface CancelNumberDto {
   documentNumber: string;
   reason: string;
-  projectId?: number;
+  projectId?: number | string; // ADR-019: Accept UUID
 }
 
 export interface AuditQueryParams {
-  projectId?: number;
+  projectId?: number | string; // ADR-019: Accept UUID
   limit?: number;
 }
diff --git a/frontend/types/dto/organization/organization.dto.ts b/frontend/types/dto/organization/organization.dto.ts
index e33d264..ee3ee64 100644
--- a/frontend/types/dto/organization/organization.dto.ts
+++ b/frontend/types/dto/organization/organization.dto.ts
@@ -4,20 +4,20 @@
 export interface CreateOrganizationDto {
   organizationCode: string;
   organizationName: string;
-  roleId?: number;
+  roleId?: number | string; // ADR-019: Accept UUID
   isActive?: boolean;
 }
 
 export interface UpdateOrganizationDto {
   organizationCode?: string;
   organizationName?: string;
-  roleId?: number;
+  roleId?: number | string; // ADR-019: Accept UUID
   isActive?: boolean;
 }
 
 export interface SearchOrganizationDto {
   search?: string;
-  projectId?: number;
+  projectId?: number | string; // ADR-019: Accept UUID
   page?: number;
   limit?: number;
   isActive?: boolean;
diff --git a/frontend/types/dto/rfa/rfa.dto.ts b/frontend/types/dto/rfa/rfa.dto.ts
index fa275f3..ef8a0b1 100644
--- a/frontend/types/dto/rfa/rfa.dto.ts
+++ b/frontend/types/dto/rfa/rfa.dto.ts
@@ -5,11 +5,11 @@ export interface CreateRfaDto {
   /** ID or UUID ของโครงการ */
   projectId: number | string; // ADR-019: Accept UUID
 
-  /** ประเภท RFA (เช่น DWG, MAT) */
-  rfaTypeId: number;
+  /** ประเภท RFA (เช่น DWG, MAT) - ADR-019: Accept UUID */
+  rfaTypeId: number | string;
 
-  /** [Req 6B] สาขางาน (จำเป็นสำหรับการรันเลข RFA) */
-  disciplineId?: number;
+  /** [Req 6B] สาขางาน (จำเป็นสำหรับการรันเลข RFA) - ADR-019: Accept UUID */
+  disciplineId?: number | string;
 
   /** หัวข้อเรื่อง */
   subject: string;
@@ -50,11 +50,11 @@ export interface SearchRfaDto {
   /** Filter by Project ID or UUID (optional to allow cross-project search) */
   projectId?: number | string; // ADR-019: Accept UUID
 
-  /** กรองตามประเภท RFA */
-  rfaTypeId?: number;
+  /** กรองตามประเภท RFA - ADR-019: Accept UUID */
+  rfaTypeId?: number | string;
 
-  /** กรองตามสถานะ (เช่น Draft, For Approve) */
-  statusId?: number;
+  /** กรองตามสถานะ (เช่น Draft, For Approve) - ADR-019: Accept UUID */
+  statusId?: number | string;
 
   /** กรองตามสถานะ code โดยตรง (เช่น 'DFT', 'FAP', 'FRE') */
   statusCode?: string;
diff --git a/frontend/types/dto/transmittal/transmittal.dto.ts b/frontend/types/dto/transmittal/transmittal.dto.ts
index d22dabe..6622b24 100644
--- a/frontend/types/dto/transmittal/transmittal.dto.ts
+++ b/frontend/types/dto/transmittal/transmittal.dto.ts
@@ -20,7 +20,7 @@ export interface CreateTransmittalDto {
 
 export interface CreateTransmittalItemDto {
   itemType: string;
-  itemId: number;
+  itemId: number | string; // ADR-019: Accept UUID
   description?: string;
 }
 
diff --git a/frontend/types/dto/user/user.dto.ts b/frontend/types/dto/user/user.dto.ts
index f6ed982..5da445b 100644
--- a/frontend/types/dto/user/user.dto.ts
+++ b/frontend/types/dto/user/user.dto.ts
@@ -17,13 +17,13 @@ export type UpdateUserDto = Partial<CreateUserDto>;
 
 // --- Assign Role ---
 export interface AssignRoleDto {
-  userId: number;
-  roleId: number;
+  userId: number | string; // ADR-019: Accept UUID
+  roleId: number | string; // ADR-019: Accept UUID
 
-  // Scope (Optional)
-  organizationId?: number;
-  projectId?: number;
-  contractId?: number;
+  // Scope (Optional) - ADR-019: Accept UUID
+  organizationId?: number | string;
+  projectId?: number | string;
+  contractId?: number | string;
 }
 
 // --- Update Preferences ---
diff --git a/frontend/types/master-data.ts b/frontend/types/master-data.ts
index a8a958f..14927eb 100644
--- a/frontend/types/master-data.ts
+++ b/frontend/types/master-data.ts
@@ -3,7 +3,8 @@
  */
 
 export interface CorrespondenceType {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   typeCode: string;
   typeName: string;
   isActive: boolean;
@@ -11,7 +12,8 @@ export interface CorrespondenceType {
 }
 
 export interface Discipline {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   disciplineCode: string;
   codeNameEn: string;
   codeNameTh?: string;
@@ -21,11 +23,12 @@ export interface Discipline {
     contractCode: string;
     contractName: string;
   };
-  contractId?: number | string;
+  contractId?: number | string; // ADR-019: Accept UUID
 }
 
 export interface RfaType {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   typeCode: string;
   typeNameTh: string;
   typeNameEn?: string;
@@ -36,25 +39,28 @@ export interface RfaType {
     contractCode: string;
     contractName: string;
   };
-  contractId?: number | string;
+  contractId?: number | string; // ADR-019: Accept UUID
 }
 
 export interface Tag {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   tagName: string;
   colorCode?: string;
   description?: string;
 }
 
 export interface DrawingCategory {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   subTypeCode: string;
   subTypeName: string;
   subTypeNumber?: string;
 }
 
 export interface ShopMainCategory {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   mainCategoryCode: string;
   mainCategoryName: string;
   name?: string; // Fallback for legacy data
@@ -62,7 +68,8 @@ export interface ShopMainCategory {
 }
 
 export interface ShopSubCategory {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   subCategoryCode: string;
   subCategoryName: string;
   name?: string; // Fallback for legacy data
@@ -70,7 +77,8 @@ export interface ShopSubCategory {
 }
 
 export interface ContractDrawingCategory {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   catCode: string;
   catName: string;
   name?: string; // Fallback for legacy data
diff --git a/frontend/types/migration.ts b/frontend/types/migration.ts
index 06952a9..58db7a6 100644
--- a/frontend/types/migration.ts
+++ b/frontend/types/migration.ts
@@ -5,7 +5,8 @@ export enum MigrationReviewStatus {
 }
 
 export interface MigrationReviewQueueItem {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   documentNumber: string;
   title?: string;
   originalTitle?: string;
@@ -17,15 +18,15 @@ export interface MigrationReviewQueueItem {
   reviewedBy?: string;
   reviewedAt?: string;
   createdAt: string;
-  projectId?: number;
-  senderOrganizationId?: number;
-  receiverOrganizationId?: number;
+  projectId?: number | string; // ADR-019: Accept UUID
+  senderOrganizationId?: number | string; // ADR-019: Accept UUID
+  receiverOrganizationId?: number | string; // ADR-019: Accept UUID
   receivedDate?: string;
   issuedDate?: string;
   remarks?: string;
   aiSummary?: string;
   extractedTags?: Record<string, unknown>;
-  tempAttachmentId?: number;
+  tempAttachmentId?: number | string; // ADR-019: Accept UUID
 }
 
 export interface CommitBatchItemDto {
@@ -48,7 +49,8 @@ export enum MigrationErrorType {
 }
 
 export interface MigrationErrorItem {
-  id: number;
+  publicId: string; // ADR-019: public identifier
+  id?: number; // Internal INT (excluded from API)
   batchId?: string;
   documentNumber?: string;
   errorType?: MigrationErrorType;
diff --git a/frontend/types/workflow.ts b/frontend/types/workflow.ts
index 33c7313..c33ffe4 100644
--- a/frontend/types/workflow.ts
+++ b/frontend/types/workflow.ts
@@ -1,7 +1,8 @@
 export type WorkflowType = 'CORRESPONDENCE' | 'RFA' | 'DRAWING';
 
 export interface WorkflowStep {
-  stepId?: string;
+  publicId: string; // ADR-019: public identifier
+  stepId?: string; // Internal ID (excluded from API)
   stepName: string;
   stepType: 'APPROVAL' | 'REVIEW' | 'ENDORSEMENT';
   approverRoleId?: number;
@@ -11,7 +12,8 @@ export interface WorkflowStep {
 }
 
 export interface Workflow {
-  workflowId: string | number;
+  publicId: string; // ADR-019: public identifier
+  workflowId?: string | number; // Internal ID (excluded from API)
   workflowName: string;
   description: string;
   workflowType: WorkflowType;