diff --git a/server/api/decorator/ParseUserLevel.ts b/server/api/decorator/ParseUserLevel.ts
new file mode 100644
index 0000000..10c6fef
--- /dev/null
+++ b/server/api/decorator/ParseUserLevel.ts
@@ -0,0 +1,32 @@
+import { type BaseConverter, InvalidConversion } from "./base";
+import { Request, Response, NextFunction } from "express";
+
+
+interface GameLoginIn {
+    userID: number;
+    [key: string]: unknown;
+}
+
+interface UserLevelOut {
+    userID: number;
+    userLevel: number;
+    [key: string]: unknown;
+}
+
+/*export class ReqGameLogin0 extends BaseConverter<SessionIn, SessionOut> {
+    override transform(inCtx: SessionIn, request: Request, response: Response): SessionOut | InvalidConversion {
+        return {
+            generalID: inCtx.userID * 4,
+            ...inCtx,
+        }
+    }
+}*/
+
+export function ParseUserLevel(): BaseConverter<GameLoginIn, UserLevelOut> {
+    return (inCtx: GameLoginIn, request: Request, response: Response): UserLevelOut | InvalidConversion => {
+        return {
+            userLevel: 123,
+            ...inCtx,
+        }
+    }
+}
\ No newline at end of file
diff --git a/server/api/decorator/base.d.ts b/server/api/decorator/base.d.ts
new file mode 100644
index 0000000..deb54ec
--- /dev/null
+++ b/server/api/decorator/base.d.ts
@@ -0,0 +1,18 @@
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+
+type C = (...args: any) => any;
+type Rev<A> = ()=> A;
+
+type ChainResult<T> =
+    T extends [infer R0 extends C] ? ReturnType<R0> :
+    T extends [infer R1 extends C, infer R0 extends C] ? ReturnType<R1> & ReturnType<R0> :
+    T extends [infer R2, infer R1, ...infer RX] ? ChainResult2<R2, R1, ChainResult<[R2, R1]>, ChainResult<[Rev<ChainResult<[R2, R1]>>, ...RX]>> :
+    never;
+
+type ChainResult2<A, B, T, ANS> = T extends ChainResult<[A, B]> ? ANS: never;
+
+declare function DeclConverter<R0 extends C>(r0: R0): [[R0], ReturnType<R0>];
+declare function DeclConverter<R0, R1>(r0: R0, r1: R1): [[R0, R1], ChainResult<[R0, R1]>];
+declare function DeclConverter<R0, R1, R2>(r0: R0, r1: R1, r2:R2) : [[R0, R1, R2], ChainResult<[R0, R1, R2]>];
+declare function DeclConverter<R0, R1, R2, R3>(r0: R0, r1: R1, r2:R2, r3:R3) : [[R0, R1, R2, R3], ChainResult<[R0, R1, R2, R3]>];
+declare function DeclConverter<R0, R1, R2, R3, R4>(r0: R0, r1: R1, r2:R2, r3:R3, r4:R4) : [[R0, R1, R2, R3, R4], ChainResult<[R0, R1, R2, R3, R4]>];
diff --git a/server/api/decorator/base.ts b/server/api/decorator/base.ts
new file mode 100644
index 0000000..4e961e4
--- /dev/null
+++ b/server/api/decorator/base.ts
@@ -0,0 +1,44 @@
+import { Request, Response, NextFunction } from "express";
+import { ReqLogin } from "./reqLogin";
+import { ReqGameLogin } from "./reqGameLogin";
+import { ParseUserLevel } from "./ParseUserLevel";
+
+export type InvalidConversion = {
+    isInvalid: true;
+    reason?: string;
+    alreadyProcessed?: boolean;
+}
+
+export interface BaseConverter<In extends object, Out extends In,>{
+    (inCtx: In, request: Request, response: Response): Out | InvalidConversion;
+}
+
+function Chain<In>(args: In, request: Request, response: Response) {
+    return {
+        next: <Out extends In,>(inner: (payload: In, request: Request, response: Response) => Out) => {
+            return Chain(inner(args, request, response), request, response);
+        }
+    }
+}
+
+type ExtendsType<U, T> = T extends U ? T : never;
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+
+
+//export function DeclConverter(): [[], Record<string, unknown>];
+
+
+//TODO: ReqLogin이 위에 있을 경우에만 통과시켜야..?
+const a = DeclConverter(
+    ParseUserLevel(),
+    ReqLogin(),
+    ReqGameLogin(),
+)
+
+type b = Exclude<(typeof a)[1], InvalidConversion>;
+const c: b = undefined as unknown as b;
+//흠....
+console.log(c.generalID);
+console.log(c.userID);
+console.log(c.userLevel);
\ No newline at end of file
diff --git a/server/api/decorator/reqGameLogin.ts b/server/api/decorator/reqGameLogin.ts
new file mode 100644
index 0000000..c1ce74a
--- /dev/null
+++ b/server/api/decorator/reqGameLogin.ts
@@ -0,0 +1,32 @@
+import { type BaseConverter, InvalidConversion } from "./base";
+import { Request, Response, NextFunction } from "express";
+
+
+interface GameLoginIn {
+    userID: number;
+    [key: string]: unknown;
+}
+
+interface GameLoginOut {
+    userID: number;
+    generalID: number;
+    [key: string]: unknown;
+}
+
+/*export class ReqGameLogin0 extends BaseConverter<SessionIn, SessionOut> {
+    override transform(inCtx: SessionIn, request: Request, response: Response): SessionOut | InvalidConversion {
+        return {
+            generalID: inCtx.userID * 4,
+            ...inCtx,
+        }
+    }
+}*/
+
+export function ReqGameLogin(): BaseConverter<GameLoginIn, GameLoginOut> {
+    return (inCtx: GameLoginIn, request: Request, response: Response): GameLoginOut | InvalidConversion => {
+        return {
+            generalID: inCtx.userID * 4,
+            ...inCtx,
+        }
+    }
+}
\ No newline at end of file
diff --git a/server/api/decorator/reqGameSession.ts b/server/api/decorator/reqGameSession.ts
deleted file mode 100644
index e69de29..0000000
diff --git a/server/api/decorator/reqLogin.ts b/server/api/decorator/reqLogin.ts
new file mode 100644
index 0000000..3c99d48
--- /dev/null
+++ b/server/api/decorator/reqLogin.ts
@@ -0,0 +1,42 @@
+import { BaseConverter, InvalidConversion } from "./base";
+import { Request, Response, NextFunction } from "express";
+
+
+interface SessionIn {
+    [key: string]: unknown;
+}
+
+interface SessionOut {
+    userID: number;
+    [key: string]: unknown;
+}
+
+/*export class ReqLogin extends BaseConverter<SessionIn, SessionOut> {
+    override transform(inCtx: SessionIn, request: Request, response: Response): SessionOut | InvalidConversion {
+        if(request.params['something'] === 'haha'){
+            return {
+                isInvalid: true,
+                reason: 'haha',
+            }
+        }
+        return {
+            generalID: inCtx.userID * 4,
+            ...inCtx,
+        }
+    }
+}*/
+
+export function ReqLogin(): BaseConverter<SessionIn, SessionOut> {
+    return (inCtx: SessionIn, request: Request, response: Response): SessionOut | InvalidConversion => {
+        if(request.params['something'] === 'haha'){
+            return {
+                isInvalid: true,
+                reason: 'haha',
+            }
+        }
+        return {
+            userID: 123,
+            ...inCtx,
+        }
+    }
+}
\ No newline at end of file
diff --git a/server/api/decorator/reqSession.ts b/server/api/decorator/reqSession.ts
deleted file mode 100644
index e69de29..0000000