diff --git a/devfront/src/features/clients/ClientGeneralPage.tsx b/devfront/src/features/clients/ClientGeneralPage.tsx
index 7c84acbe..abb9610e 100644
--- a/devfront/src/features/clients/ClientGeneralPage.tsx
+++ b/devfront/src/features/clients/ClientGeneralPage.tsx
@@ -59,6 +59,17 @@ interface ScopeItem {
   locked?: boolean;
 }
 
+type ClaimNamespace = "top_level" | "rp_claims";
+type ClaimValueType = "text" | "number" | "boolean" | "array" | "object";
+
+interface IdTokenClaimItem {
+  id: string;
+  namespace: ClaimNamespace;
+  key: string;
+  value: string;
+  valueType: ClaimValueType;
+}
+
 type SecurityProfile = "private" | "pkce";
 type TokenEndpointAuthMethod =
   | "none"
@@ -111,6 +122,142 @@ function readMetadataString(
   return typeof value === "string" ? value : "";
 }
 
+function isClaimNamespace(value: string): value is ClaimNamespace {
+  return value === "top_level" || value === "rp_claims";
+}
+
+function isClaimValueType(value: string): value is ClaimValueType {
+  return (
+    value === "text" ||
+    value === "number" ||
+    value === "boolean" ||
+    value === "array" ||
+    value === "object"
+  );
+}
+
+function createIdTokenClaimItem(id: string): IdTokenClaimItem {
+  return {
+    id,
+    namespace: "top_level",
+    key: "",
+    value: "",
+    valueType: "text",
+  };
+}
+
+function readIdTokenClaimsMetadata(
+  metadata: Record<string, unknown>,
+): IdTokenClaimItem[] {
+  const rawClaims = metadata.id_token_claims;
+  if (!Array.isArray(rawClaims)) {
+    return [];
+  }
+
+  return rawClaims
+    .map((item, index) => {
+      if (!item || typeof item !== "object") {
+        return null;
+      }
+
+      const record = item as Record<string, unknown>;
+      const namespaceValue =
+        typeof record.namespace === "string" &&
+        isClaimNamespace(record.namespace)
+          ? record.namespace
+          : "top_level";
+      const keyValue = typeof record.key === "string" ? record.key : "";
+      const rawValue = record.value;
+      const valueValue =
+        typeof rawValue === "string"
+          ? rawValue
+          : rawValue == null
+            ? ""
+            : JSON.stringify(rawValue);
+      const valueTypeValue =
+        typeof record.valueType === "string" &&
+        isClaimValueType(record.valueType)
+          ? record.valueType
+          : "text";
+
+      return {
+        id: `claim-${index + 1}`,
+        namespace: namespaceValue,
+        key: keyValue,
+        value: valueValue,
+        valueType: valueTypeValue,
+      };
+    })
+    .filter((item): item is IdTokenClaimItem => item !== null);
+}
+
+function normalizeClaimPreviewValue(
+  value: string,
+  valueType: ClaimValueType,
+): unknown {
+  const trimmed = value.trim();
+  if (valueType === "number") {
+    if (trimmed === "") return "";
+    const parsed = Number(trimmed);
+    return Number.isFinite(parsed) ? parsed : trimmed;
+  }
+
+  if (valueType === "boolean") {
+    return ["true", "1", "yes", "on"].includes(trimmed.toLowerCase());
+  }
+
+  if (valueType === "array") {
+    if (trimmed === "") return [];
+    try {
+      if (trimmed.startsWith("[")) {
+        const parsed = JSON.parse(trimmed);
+        return Array.isArray(parsed) ? parsed : [parsed];
+      }
+    } catch {
+      // Fall through to comma-separated parsing.
+    }
+    return trimmed
+      .split(",")
+      .map((part) => part.trim())
+      .filter(Boolean);
+  }
+
+  if (valueType === "object") {
+    if (trimmed === "") return {};
+    try {
+      const parsed = JSON.parse(trimmed);
+      return parsed;
+    } catch {
+      return trimmed;
+    }
+  }
+
+  return trimmed;
+}
+
+function buildIdTokenClaimsPreview(
+  items: IdTokenClaimItem[],
+): Record<string, unknown> {
+  const preview: Record<string, unknown> = {};
+  const rpClaims: Record<string, unknown> = {};
+
+  for (const item of items) {
+    const key = item.key.trim();
+    if (!key) {
+      continue;
+    }
+
+    const target = item.namespace === "rp_claims" ? rpClaims : preview;
+    target[key] = normalizeClaimPreviewValue(item.value, item.valueType);
+  }
+
+  if (Object.keys(rpClaims).length > 0) {
+    preview.rp_claims = rpClaims;
+  }
+
+  return preview;
+}
+
 function isValidUrl(value: string): boolean {
   try {
     const url = new URL(value);
@@ -192,6 +339,7 @@ function ClientGeneralPage() {
       mandatory: false,
     },
   ]);
+  const [idTokenClaims, setIdTokenClaims] = useState<IdTokenClaimItem[]>([]);
 
   useEffect(() => {
     if (!data) return;
@@ -287,6 +435,7 @@ function ClientGeneralPage() {
         ),
       );
     }
+    setIdTokenClaims(readIdTokenClaimsMetadata(metadata));
   }, [data]);
 
   const securityProfile: SecurityProfile =
@@ -436,6 +585,32 @@ function ClientGeneralPage() {
     );
   };
 
+  const addIdTokenClaim = () => {
+    setIdTokenClaims((current) => [
+      ...current,
+      createIdTokenClaimItem(`claim-${Date.now()}`),
+    ]);
+  };
+
+  const updateIdTokenClaim = <K extends keyof IdTokenClaimItem>(
+    id: string,
+    field: K,
+    value: IdTokenClaimItem[K],
+  ) => {
+    setIdTokenClaims((current) =>
+      current.map((claim) => {
+        if (claim.id !== id) {
+          return claim;
+        }
+        return { ...claim, [field]: value };
+      }),
+    );
+  };
+
+  const removeIdTokenClaim = (id: string) => {
+    setIdTokenClaims((current) => current.filter((claim) => claim.id !== id));
+  };
+
   const handleStatusChange = (nextStatus: ClientStatus) => {
     setStatus(nextStatus);
     const statusLabel =
@@ -487,6 +662,11 @@ function ClientGeneralPage() {
     "허용 알고리즘: {{algorithms}}",
     { algorithms: HEADLESS_LOGIN_ALLOWED_ALGORITHMS.join(", ") },
   );
+  const normalizedIdTokenClaims = idTokenClaims.map((claim) => ({
+    ...claim,
+    key: claim.key.trim(),
+    value: claim.value.trim(),
+  }));
 
   if (headlessLoginEnabled) {
     if (!trimmedJwksUri) {
@@ -541,7 +721,61 @@ function ClientGeneralPage() {
     );
   }
 
+  const claimValidationErrors: string[] = [];
+  const seenClaimKeys = new Set<string>();
+  for (const claim of normalizedIdTokenClaims) {
+    if (!claim.key) {
+      claimValidationErrors.push(
+        t(
+          "msg.dev.clients.general.id_token_claims.key_required",
+          "Claim key를 입력해야 합니다.",
+        ),
+      );
+      continue;
+    }
+
+    if (claim.key === "rp_claims" && claim.namespace === "top_level") {
+      claimValidationErrors.push(
+        t(
+          "msg.dev.clients.general.id_token_claims.reserved_key",
+          "`rp_claims`는 예약된 namespace 키입니다.",
+        ),
+      );
+      continue;
+    }
+
+    const keySignature = `${claim.namespace}:${claim.key}`;
+    if (seenClaimKeys.has(keySignature)) {
+      claimValidationErrors.push(
+        t(
+          "msg.dev.clients.general.id_token_claims.duplicate_key",
+          "중복된 claim key가 있습니다: {{namespace}}.{{key}}",
+          {
+            namespace:
+              claim.namespace === "rp_claims"
+                ? t(
+                    "ui.dev.clients.general.id_token_claims.namespace_rp_claims",
+                    "rp_claims",
+                  )
+                : t(
+                    "ui.dev.clients.general.id_token_claims.namespace_top_level",
+                    "top-level",
+                  ),
+            key: claim.key,
+          },
+        ),
+      );
+      continue;
+    }
+    seenClaimKeys.add(keySignature);
+  }
+  validationErrors.push(...claimValidationErrors);
+
   const hasValidationErrors = validationErrors.length > 0;
+  const idTokenClaimPreview = buildIdTokenClaimsPreview(
+    normalizedIdTokenClaims,
+  );
+  const idTokenClaimPreviewJson = JSON.stringify(idTokenClaimPreview, null, 2);
   const normalizedTenantSearch = tenantSearch.trim().toLowerCase();
   const tenantOptions: Array<TenantSummary | MyTenantSummary> =
     tenantData ?? [];
@@ -676,6 +910,7 @@ function ClientGeneralPage() {
           auto_login_supported: autoLoginSupported,
           auto_login_url: autoLoginSupported ? trimmedAutoLoginUrl : undefined,
           structured_scopes: normalizedScopes,
+          id_token_claims: normalizedIdTokenClaims,
           token_endpoint_auth_method: effectiveTokenEndpointAuthMethod,
           headless_login_enabled: headlessLoginEnabled,
           headless_token_endpoint_auth_method:
@@ -1534,6 +1769,249 @@ function ClientGeneralPage() {
         </CardContent>
       </Card>
 
+      <Card className="glass-panel">
+        <CardHeader className="pb-4">
+          <div className="flex flex-col gap-2 md:flex-row md:items-start md:justify-between">
+            <div className="space-y-1">
+              <CardTitle className="text-xl font-bold">
+                {t(
+                  "ui.dev.clients.general.id_token_claims.title",
+                  "ID Token Claims",
+                )}
+              </CardTitle>
+              <CardDescription>
+                {t(
+                  "msg.dev.clients.general.id_token_claims.subtitle",
+                  "공통 claim과 RP 전용 확장 claim을 구분해서 관리합니다.",
+                )}
+              </CardDescription>
+            </div>
+            <Button onClick={addIdTokenClaim} className="gap-2">
+              <Plus className="h-4 w-4" />
+              {t("ui.dev.clients.general.id_token_claims.add", "Claim 추가")}
+            </Button>
+          </div>
+        </CardHeader>
+        <CardContent className="space-y-4">
+          <div className="grid gap-4 xl:grid-cols-[1.3fr_0.7fr]">
+            <div className="space-y-3">
+              <div className="rounded-md border border-border overflow-hidden">
+                <table className="w-full text-sm">
+                  <thead className="bg-muted/50 border-b border-border text-xs uppercase tracking-wider text-muted-foreground">
+                    <tr>
+                      <th className="px-4 py-3 text-left font-bold">
+                        {t(
+                          "ui.dev.clients.general.id_token_claims.table.key",
+                          "Claim Key",
+                        )}
+                      </th>
+                      <th className="px-4 py-3 text-left font-bold">
+                        {t(
+                          "ui.dev.clients.general.id_token_claims.table.namespace",
+                          "Namespace",
+                        )}
+                      </th>
+                      <th className="px-4 py-3 text-left font-bold">
+                        {t(
+                          "ui.dev.clients.general.id_token_claims.table.value_type",
+                          "Value Type",
+                        )}
+                      </th>
+                      <th className="px-4 py-3 text-left font-bold">
+                        {t(
+                          "ui.dev.clients.general.id_token_claims.table.value",
+                          "Value",
+                        )}
+                      </th>
+                      <th className="px-4 py-3 text-right font-bold">
+                        {t(
+                          "ui.dev.clients.general.id_token_claims.table.delete",
+                          "Delete",
+                        )}
+                      </th>
+                    </tr>
+                  </thead>
+                  <tbody className="divide-y divide-border">
+                    {idTokenClaims.map((claim) => (
+                      <tr key={claim.id} className="hover:bg-muted/20">
+                        <td className="px-4 py-3 align-top">
+                          <Input
+                            value={claim.key}
+                            onChange={(e) =>
+                              updateIdTokenClaim(
+                                claim.id,
+                                "key",
+                                e.target.value,
+                              )
+                            }
+                            className="h-9 font-mono text-xs"
+                            placeholder={t(
+                              "ui.dev.clients.general.id_token_claims.key_placeholder",
+                              "e.g. locale",
+                            )}
+                          />
+                        </td>
+                        <td className="px-4 py-3 align-top">
+                          <select
+                            value={claim.namespace}
+                            onChange={(e) =>
+                              updateIdTokenClaim(
+                                claim.id,
+                                "namespace",
+                                e.target.value as ClaimNamespace,
+                              )
+                            }
+                            aria-label={t(
+                              "ui.dev.clients.general.id_token_claims.namespace_label",
+                              "Claim namespace",
+                            )}
+                            className="h-9 w-full rounded-md border border-input bg-background px-3 text-sm shadow-sm transition-colors focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring"
+                          >
+                            <option value="top_level">
+                              {t(
+                                "ui.dev.clients.general.id_token_claims.namespace_top_level",
+                                "top-level",
+                              )}
+                            </option>
+                            <option value="rp_claims">
+                              {t(
+                                "ui.dev.clients.general.id_token_claims.namespace_rp_claims",
+                                "rp_claims",
+                              )}
+                            </option>
+                          </select>
+                        </td>
+                        <td className="px-4 py-3 align-top">
+                          <select
+                            value={claim.valueType}
+                            onChange={(e) =>
+                              updateIdTokenClaim(
+                                claim.id,
+                                "valueType",
+                                e.target.value as ClaimValueType,
+                              )
+                            }
+                            aria-label={t(
+                              "ui.dev.clients.general.id_token_claims.value_type_label",
+                              "Claim value type",
+                            )}
+                            className="h-9 w-full rounded-md border border-input bg-background px-3 text-sm shadow-sm transition-colors focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring"
+                          >
+                            <option value="text">
+                              {t(
+                                "ui.dev.clients.general.id_token_claims.value_type_text",
+                                "Text",
+                              )}
+                            </option>
+                            <option value="number">
+                              {t(
+                                "ui.dev.clients.general.id_token_claims.value_type_number",
+                                "Number",
+                              )}
+                            </option>
+                            <option value="boolean">
+                              {t(
+                                "ui.dev.clients.general.id_token_claims.value_type_boolean",
+                                "Boolean",
+                              )}
+                            </option>
+                            <option value="array">
+                              {t(
+                                "ui.dev.clients.general.id_token_claims.value_type_array",
+                                "Array",
+                              )}
+                            </option>
+                            <option value="object">
+                              {t(
+                                "ui.dev.clients.general.id_token_claims.value_type_object",
+                                "Object",
+                              )}
+                            </option>
+                          </select>
+                        </td>
+                        <td className="px-4 py-3 align-top">
+                          <Input
+                            value={claim.value}
+                            onChange={(e) =>
+                              updateIdTokenClaim(
+                                claim.id,
+                                "value",
+                                e.target.value,
+                              )
+                            }
+                            className="h-9 font-mono text-xs"
+                            placeholder={t(
+                              "ui.dev.clients.general.id_token_claims.value_placeholder",
+                              "Enter the claim value",
+                            )}
+                          />
+                        </td>
+                        <td className="px-4 py-3 text-right align-top">
+                          <Button
+                            variant="ghost"
+                            size="icon"
+                            onClick={() => removeIdTokenClaim(claim.id)}
+                            className="h-9 w-9 text-muted-foreground hover:text-destructive"
+                          >
+                            <Trash2 className="h-4 w-4" />
+                          </Button>
+                        </td>
+                      </tr>
+                    ))}
+                    {idTokenClaims.length === 0 && (
+                      <tr>
+                        <td
+                          colSpan={5}
+                          className="px-4 py-8 text-center text-muted-foreground"
+                        >
+                          {t(
+                            "msg.dev.clients.general.id_token_claims.empty",
+                            "아직 추가된 ID Token claim이 없습니다.",
+                          )}
+                        </td>
+                      </tr>
+                    )}
+                  </tbody>
+                </table>
+              </div>
+              <p className="text-xs leading-6 text-muted-foreground">
+                {t(
+                  "msg.dev.clients.general.id_token_claims.hint",
+                  "top-level은 일반 claim에, rp_claims는 RP 전용 확장 claim에 사용합니다. 배열은 JSON 또는 콤마 구분 문자열, 객체는 JSON을 입력하면 됩니다.",
+                )}
+              </p>
+            </div>
+
+            <div className="space-y-3">
+              <div className="rounded-xl border border-border bg-muted/20 p-4">
+                <div className="flex items-center gap-2">
+                  <Info className="h-4 w-4 text-primary" />
+                  <div>
+                    <p className="text-sm font-semibold">
+                      {t(
+                        "ui.dev.clients.general.id_token_claims.preview_title",
+                        "Saved JSON Preview",
+                      )}
+                    </p>
+                    <p className="text-xs text-muted-foreground">
+                      {t(
+                        "msg.dev.clients.general.id_token_claims.preview_hint",
+                        "저장될 metadata.id_token_claims 구조를 미리 확인할 수 있습니다.",
+                      )}
+                    </p>
+                  </div>
+                </div>
+                <Textarea
+                  readOnly
+                  value={idTokenClaimPreviewJson}
+                  className="mt-4 min-h-72 font-mono text-xs"
+                />
+              </div>
+            </div>
+          </div>
+        </CardContent>
+      </Card>
+
       {/* 3. Security Settings */}
       <Card className="glass-panel">
         <CardHeader className="pb-3">
diff --git a/devfront/src/locales/en.toml b/devfront/src/locales/en.toml
index 8212652f..17077a4a 100644
--- a/devfront/src/locales/en.toml
+++ b/devfront/src/locales/en.toml
@@ -421,6 +421,15 @@ empty = "No scopes registered."
 subtitle = "Define the permission scopes this application can request."
 tenant = "Tenant access claim"
 
+[msg.dev.clients.general.id_token_claims]
+subtitle = "Separate shared claims from RP-specific extension claims."
+empty = "No ID Token claims have been added yet."
+hint = "Use top-level for shared claims and rp_claims for RP-specific extension claims. Arrays accept JSON or comma-separated values, and objects accept JSON."
+preview_hint = "Preview the metadata.id_token_claims structure that will be saved."
+key_required = "Enter a claim key."
+reserved_key = "`rp_claims` is a reserved namespace key."
+duplicate_key = "Duplicate claim key: {{namespace}}.{{key}}"
+
 [msg.dev.clients.general.security]
 private_help = "Server side App: For apps that can safely store a client secret, such as Node.js or Java servers."
 pkce_help = "PKCE App (SPA/Mobile): For apps that cannot safely store a client secret. PKCE is mandatory."
@@ -1452,6 +1461,22 @@ hint = "Turning this on adds the tenant scope automatically and requires at leas
 autocomplete_hint = "Type a tenant name to see autocomplete suggestions. Click one to add it to the allowed list."
 validation_required = "Select at least one allowed tenant when tenant access restriction is enabled."
 
+[ui.dev.clients.general.id_token_claims]
+title = "ID Token Claims"
+add = "Add Claim"
+preview_title = "Saved JSON Preview"
+namespace_label = "Claim namespace"
+namespace_top_level = "top-level"
+namespace_rp_claims = "rp_claims"
+value_type_label = "Claim value type"
+value_type_text = "Text"
+value_type_number = "Number"
+value_type_boolean = "Boolean"
+value_type_array = "Array"
+value_type_object = "Object"
+key_placeholder = "e.g. locale"
+value_placeholder = "Enter the claim value"
+
 [ui.dev.clients.general.security]
 private = "Server Side App"
 pkce = "PKCE"
diff --git a/devfront/src/locales/ko.toml b/devfront/src/locales/ko.toml
index 72729806..b46e0428 100644
--- a/devfront/src/locales/ko.toml
+++ b/devfront/src/locales/ko.toml
@@ -421,6 +421,15 @@ empty = "등록된 스코프가 없습니다."
 subtitle = "이 앱이 요청할 수 있는 권한 범위를 정의합니다."
 tenant = "소속 테넌트 정보 접근"
 
+[msg.dev.clients.general.id_token_claims]
+subtitle = "공통 claim과 RP 전용 확장 claim을 구분해서 관리합니다."
+empty = "아직 추가된 ID Token claim이 없습니다."
+hint = "top-level은 공통 claim에, rp_claims는 RP 전용 확장 claim에 사용합니다. 배열은 JSON 또는 콤마 구분 문자열, 객체는 JSON을 입력하면 됩니다."
+preview_hint = "저장될 metadata.id_token_claims 구조를 미리 확인할 수 있습니다."
+key_required = "Claim key를 입력해야 합니다."
+reserved_key = "`rp_claims`는 예약된 namespace 키입니다."
+duplicate_key = "중복된 claim key가 있습니다: {{namespace}}.{{key}}"
+
 [msg.dev.clients.general.security]
 pkce_help = "PKCE 앱 (SPA/모바일): 브라우저나 앱처럼 비밀키를 보관하기 어려운 경우 사용하며, PKCE가 강제됩니다."
 private_help = "Server side App (서버 사이드 앱): Node.js, Java 등 비밀키를 안전하게 보관 가능한 경우 사용합니다."
@@ -1451,6 +1460,22 @@ hint = "제한을 켜면 tenant 스코프가 자동으로 포함되며, 허용 
 autocomplete_hint = "테넌트 이름을 입력하면 자동 완성 후보가 나타납니다. 클릭하면 허용 목록에 추가됩니다."
 validation_required = "테넌트 접근 제한을 사용할 경우 허용 테넌트를 하나 이상 선택해야 합니다."
 
+[ui.dev.clients.general.id_token_claims]
+title = "ID Token Claims"
+add = "Claim 추가"
+preview_title = "저장 JSON 미리보기"
+namespace_label = "Claim 네임스페이스"
+namespace_top_level = "top-level"
+namespace_rp_claims = "rp_claims"
+value_type_label = "Claim 값 타입"
+value_type_text = "텍스트"
+value_type_number = "숫자"
+value_type_boolean = "불리언"
+value_type_array = "배열"
+value_type_object = "객체"
+key_placeholder = "예: locale"
+value_placeholder = "Claim 값을 입력하세요"
+
 [ui.dev.clients.general.security]
 private = "Server side App"
 pkce = "PKCE"
diff --git a/devfront/src/locales/template.toml b/devfront/src/locales/template.toml
index 3ce81004..91f3e09d 100644
--- a/devfront/src/locales/template.toml
+++ b/devfront/src/locales/template.toml
@@ -426,6 +426,15 @@ save_error = ""
 save_forbidden = ""
 status_changed = ""
 
+[msg.dev.clients.general.id_token_claims]
+subtitle = ""
+empty = ""
+hint = ""
+preview_hint = ""
+key_required = ""
+reserved_key = ""
+duplicate_key = ""
+
 [msg.dev.clients.relationships]
 subtitle = ""
 add_description = ""
@@ -1534,6 +1543,22 @@ hint = ""
 autocomplete_hint = ""
 validation_required = ""
 
+[ui.dev.clients.general.id_token_claims]
+title = ""
+add = ""
+preview_title = ""
+namespace_label = ""
+namespace_top_level = ""
+namespace_rp_claims = ""
+value_type_label = ""
+value_type_text = ""
+value_type_number = ""
+value_type_boolean = ""
+value_type_array = ""
+value_type_object = ""
+key_placeholder = ""
+value_placeholder = ""
+
 [ui.dev.clients.general.security]
 private = ""
 pkce = ""