Index: frontend/src/api/axiosInstance.ts
===================================================================
--- frontend/src/api/axiosInstance.ts	(revision 0c86e77a055e354a71be0ff7c053051ca180993b)
+++ frontend/src/api/axiosInstance.ts	(revision 0c86e77a055e354a71be0ff7c053051ca180993b)
@@ -0,0 +1,78 @@
+import axios from "axios";
+
+export const baseURL = import.meta.env.VITE_API_BASE_URL;
+
+export const axiosInstance = axios.create({
+	baseURL,
+	headers: {
+		"Content-Type": "application/json",
+	},
+	withCredentials: true,
+});
+
+let refreshPromise: Promise<void> | null = null;
+let refreshTimeout: number | null = null;
+
+export const clearRefreshTimeout = () => {
+	if (refreshTimeout) {
+		clearTimeout(refreshTimeout);
+		refreshTimeout = null;
+	}
+};
+
+export const scheduleTokenRefresh = (expiryTimeSeconds: number) => {
+	clearRefreshTimeout();
+
+	const refreshTime = (expiryTimeSeconds - 60) * 1000;
+	if (refreshTime <= 0) {
+		refreshTokenMethod();
+	} else {
+		refreshTimeout = setTimeout(refreshTokenMethod, refreshTime);
+	}
+};
+
+export const refreshTokenMethod = async (): Promise<void | null> => {
+	if (refreshPromise) {
+		return refreshPromise;
+	}
+
+	refreshPromise = (async () => {
+		try {
+			const refreshResponse = await axiosInstance.post<{
+				tokenExpiresIn: number;
+			}>("/auth/refresh");
+			scheduleTokenRefresh(refreshResponse.data.tokenExpiresIn);
+		} catch (err) {
+			console.error(err);
+			throw err;
+		} finally {
+			refreshPromise = null;
+		}
+	})();
+	return refreshPromise;
+};
+
+axios.interceptors.response.use(
+	(response) => response,
+	async (error) => {
+		const originalConfig = error.config;
+		if (
+			[401, 403].includes(error.response?.status) &&
+			!originalConfig._retry &&
+			originalConfig.url !== "/auth/refresh"
+		) {
+			originalConfig._retry = true;
+
+			try {
+				await refreshTokenMethod();
+				return axiosInstance(originalConfig);
+			} catch (err) {
+				clearRefreshTimeout();
+				return Promise.reject(err);
+			}
+		}
+		return Promise.reject(error);
+	},
+);
+
+export default axiosInstance;