diff --git a/packages/engine.io/lib/contrib/cookie.types.d.ts b/packages/engine.io/lib/contrib/types.cookie.ts
similarity index 80%
rename from packages/engine.io/lib/contrib/cookie.types.d.ts
rename to packages/engine.io/lib/contrib/types.cookie.ts
index 78c2b2fe6..7e546707e 100644
--- a/packages/engine.io/lib/contrib/cookie.types.d.ts
+++ b/packages/engine.io/lib/contrib/types.cookie.ts
@@ -115,48 +115,3 @@ export interface CookieSerializeOptions {
    */
   secure?: boolean | undefined;
 }
-
-/**
- * Additional parsing options
- */
-export interface CookieParseOptions {
-  /**
-   * Specifies a function that will be used to decode a cookie's value. Since
-   * the value of a cookie has a limited character set (and must be a simple
-   * string), this function can be used to decode a previously-encoded cookie
-   * value into a JavaScript string or other object.
-   *
-   * The default function is the global `decodeURIComponent`, which will decode
-   * any URL-encoded sequences into their byte representations.
-   *
-   * *Note* if an error is thrown from this function, the original, non-decoded
-   * cookie value will be returned as the cookie's value.
-   */
-  decode?(value: string): string;
-}
-
-/**
- * Parse an HTTP Cookie header string and returning an object of all cookie
- * name-value pairs.
- *
- * @param str the string representing a `Cookie` header value
- * @param [options] object containing parsing options
- */
-export function parse(
-  str: string,
-  options?: CookieParseOptions,
-): Record<string, string>;
-
-/**
- * Serialize a cookie name-value pair into a `Set-Cookie` header string.
- *
- * @param name the name for the cookie
- * @param value value to set the cookie to
- * @param [options] object containing serialization options
- * @throws {TypeError} when `maxAge` options is invalid
- */
-export function serialize(
-  name: string,
-  value: string,
-  options?: CookieSerializeOptions,
-): string;
diff --git a/packages/engine.io/lib/server.ts b/packages/engine.io/lib/server.ts
index 24576b131..bf53f994a 100644
--- a/packages/engine.io/lib/server.ts
+++ b/packages/engine.io/lib/server.ts
@@ -17,7 +17,7 @@ import type { Duplex } from "stream";
 import { WebTransport } from "./transports/webtransport";
 import { createPacketDecoderStream } from "engine.io-parser";
 import type { EngineRequest } from "./transport";
-import { CookieSerializeOptions } from "./contrib/cookie.types";
+import type { CookieSerializeOptions } from "./contrib/types.cookie";
 
 const debug = debugModule("engine");