diff --git a/src/core/baseClient.ts b/src/core/baseClient.ts
index 6aec0e9..72e8bee 100644
--- a/src/core/baseClient.ts
+++ b/src/core/baseClient.ts
@@ -59,7 +59,7 @@ export class BaseClient {
 		const pingFormData = new URLSearchParams();
 		pingFormData.append("include_data", "true");
 		const pingData = await this.makeAuthedRequest(
-			this.API_BASE + "/ping",
+			`${this.API_BASE}/ping`,
 			{
 				method: "POST",
 				body: pingFormData,
@@ -82,20 +82,17 @@ export class BaseClient {
 	public async makeAuthedRequest(
 		path: string,
 		fetchOptions: RequestInit,
-		options?: { revalidateToken?: boolean },
+		options: { revalidateToken?: boolean } = { revalidateToken: true },
 	) {
 		if (!this.sessionId) throw new Error("No session ID");
-		if (!options) {
-			options = {};
-		}
-		if (typeof options?.revalidateToken == "undefined") {
+		if (typeof options?.revalidateToken === "undefined") {
 			options.revalidateToken = true;
 		}
 		const requestOptions = {
 			...fetchOptions,
 			headers: {
 				Cookie: this?.authCookies?.join(";") ?? [],
-				Authorization: "Basic " + this.sessionId,
+				Authorization: `Basic ${this.sessionId}`,
 				"User-Agent":
 					"classcharts-api https://github.com/classchartsapi/classcharts-api-js",
 				...fetchOptions.headers,
@@ -107,16 +104,16 @@ export class BaseClient {
 			}
 		}
 		const request = await fetch(path, requestOptions);
-		// deno-lint-ignore no-explicit-any
+		// biome-ignore lint/suspicious/noExplicitAny:
 		let responseJSON: ClassChartsResponse<any, any>;
 		try {
 			responseJSON = await request.json();
 		} catch {
 			throw new Error(
-				"Error parsing JSON. Returned response: " + (await request.text()),
+				`Error parsing JSON. Returned response: ${await request.text()}`,
 			);
 		}
-		if (responseJSON.success == 0) {
+		if (responseJSON.success === 0) {
 			throw new Error(responseJSON.error);
 		}
 		return responseJSON;
@@ -128,7 +125,7 @@ export class BaseClient {
 	async getStudentInfo(): Promise<GetStudentInfoResponse> {
 		const body = new URLSearchParams();
 		body.append("include_data", "true");
-		return await this.makeAuthedRequest(this.API_BASE + "/ping", {
+		return await this.makeAuthedRequest(`${this.API_BASE}/ping`, {
 			method: "POST",
 			body: body,
 		});
@@ -147,7 +144,7 @@ export class BaseClient {
 		options?.to && params.append("to", options?.to);
 		options?.last_id && params.append("last_id", options?.last_id);
 		return await this.makeAuthedRequest(
-			this.API_BASE + "/activity/" + this.studentId + "?" + params.toString(),
+			`${this.API_BASE}/activity/${this.studentId}?${params.toString()}`,
 			{
 				method: "GET",
 			},
@@ -197,7 +194,7 @@ export class BaseClient {
 		options?.from && params.append("from", options?.from);
 		options?.to && params.append("to", options?.to);
 		return await this.makeAuthedRequest(
-			this.API_BASE + "/behaviour/" + this.studentId + "?" + params.toString(),
+			`${this.API_BASE}/behaviour/${this.studentId}?${params.toString()}`,
 			{
 				method: "GET",
 			},
@@ -217,7 +214,7 @@ export class BaseClient {
 		options?.from && params.append("from", String(options?.from));
 		options?.to && params.append("to", String(options?.to));
 		return await this.makeAuthedRequest(
-			this.API_BASE + "/homeworks/" + this.studentId + "?" + params.toString(),
+			`${this.API_BASE}/homeworks/${this.studentId}?${params.toString()}`,
 			{
 				method: "GET",
 			},
@@ -233,7 +230,7 @@ export class BaseClient {
 		const params = new URLSearchParams();
 		params.append("date", String(options?.date));
 		return await this.makeAuthedRequest(
-			this.API_BASE + "/timetable/" + this.studentId + "?" + params.toString(),
+			`${this.API_BASE}/timetable/${this.studentId}?${params.toString()}`,
 			{
 				method: "GET",
 			},
@@ -245,7 +242,7 @@ export class BaseClient {
 	 */
 	async getBadges(): Promise<BadgesResponse> {
 		return await this.makeAuthedRequest(
-			this.API_BASE + "/eventbadges/" + this.studentId,
+			`${this.API_BASE}/eventbadges/${this.studentId}`,
 			{
 				method: "GET",
 			},
@@ -257,7 +254,7 @@ export class BaseClient {
 	 */
 	async getAnnouncements(): Promise<AnnouncementsResponse> {
 		return await this.makeAuthedRequest(
-			this.API_BASE + "/announcements/" + this.studentId,
+			`${this.API_BASE}/announcements/${this.studentId}`,
 			{
 				method: "GET",
 			},
@@ -269,7 +266,7 @@ export class BaseClient {
 	 */
 	async getDetentions(): Promise<DetentionsResponse> {
 		return await this.makeAuthedRequest(
-			this.API_BASE + "/detentions/" + this.studentId,
+			`${this.API_BASE}/detentions/${this.studentId}`,
 			{
 				method: "GET",
 			},
@@ -287,7 +284,7 @@ export class BaseClient {
 		options?.from && params.append("from", options?.from);
 		options?.to && params.append("to", options?.to);
 		return await this.makeAuthedRequest(
-			this.API_BASE + "/attendance/" + this.studentId + "?" + params.toString(),
+			`${this.API_BASE}/attendance/${this.studentId}?${params.toString()}`,
 			{
 				method: "GET",
 			},
@@ -299,7 +296,7 @@ export class BaseClient {
 	 */
 	async getPupilFields(): Promise<PupilFieldsResponse> {
 		return await this.makeAuthedRequest(
-			this.API_BASE + "/customfields/" + this.studentId,
+			`${this.API_BASE}/customfields/${this.studentId}`,
 			{
 				method: "GET",
 			},
diff --git a/src/core/parentClient.ts b/src/core/parentClient.ts
index 7d04159..a605bec 100644
--- a/src/core/parentClient.ts
+++ b/src/core/parentClient.ts
@@ -36,13 +36,13 @@ export class ParentClient extends BaseClient {
 		const headers = new Headers({
 			"Content-Type": "application/x-www-form-urlencoded",
 		});
-		const response = await fetch(BASE_URL + "/parent/login", {
+		const response = await fetch(`${BASE_URL}/parent/login`, {
 			method: "POST",
 			body: formData,
 			headers: headers,
 			redirect: "manual",
 		});
-		if (response.status != 302 || !response.headers.has("set-cookie")) {
+		if (response.status !== 302 || !response.headers.has("set-cookie")) {
 			await response.body?.cancel(); // Make deno tests happy by closing the body, unsure whether this is needed for the actual library
 			throw new Error(
 				"Unauthenticated: ClassCharts didn't return authentication cookies",
@@ -53,7 +53,7 @@ export class ParentClient extends BaseClient {
 		// this.authCookies = cookies.split(";");
 		const sessionCookies = parseCookies(cookies);
 		const sessionID = JSON.parse(
-			String(sessionCookies["parent_session_credentials"]),
+			String(sessionCookies.parent_session_credentials),
 		);
 		this.sessionId = sessionID.session_id;
 		this.pupils = await this.getPupils();
@@ -65,7 +65,7 @@ export class ParentClient extends BaseClient {
 	 * @returns an array of Pupils connected to this parent's account
 	 */
 	async getPupils(): Promise<GetPupilsResponse> {
-		const response = await this.makeAuthedRequest(this.API_BASE + "/pupils", {
+		const response = await this.makeAuthedRequest(`${this.API_BASE}/pupils`, {
 			method: "GET",
 		});
 		return response.data;
@@ -81,7 +81,7 @@ export class ParentClient extends BaseClient {
 		const pupils = this.pupils;
 		for (let i = 0; i < pupils.length; i++) {
 			const pupil = pupils[i];
-			if (pupil.id == pupilId) {
+			if (pupil.id === pupilId) {
 				this.studentId = pupil.id;
 				return;
 			}
@@ -102,7 +102,7 @@ export class ParentClient extends BaseClient {
 		formData.append("current", currentPassword);
 		formData.append("new", newPassword);
 		formData.append("repeat", newPassword);
-		return await this.makeAuthedRequest(this.API_BASE + "/password", {
+		return await this.makeAuthedRequest(`${this.API_BASE}/password`, {
 			method: "POST",
 			body: formData,
 			headers: {
diff --git a/src/core/studentClient.ts b/src/core/studentClient.ts
index 0514977..b4264f5 100644
--- a/src/core/studentClient.ts
+++ b/src/core/studentClient.ts
@@ -42,12 +42,12 @@ export class StudentClient extends BaseClient {
 		formData.append("dob", this.dateOfBirth);
 		formData.append("remember_me", "1");
 		formData.append("recaptcha-token", "no-token-available");
-		const request = await fetch(BASE_URL + "/student/login", {
+		const request = await fetch(`${BASE_URL}/student/login`, {
 			method: "POST",
 			body: formData,
 			redirect: "manual",
 		});
-		if (request.status != 302 || !request.headers.has("set-cookie")) {
+		if (request.status !== 302 || !request.headers.has("set-cookie")) {
 			await request.body?.cancel(); // Make deno tests happy by closing the body, unsure whether this is needed for the actual library
 			throw new Error(
 				"Unauthenticated: ClassCharts didn't return authentication cookies",
@@ -57,7 +57,7 @@ export class StudentClient extends BaseClient {
 		this.authCookies = cookies.split(",");
 		const sessionCookies = parseCookies(cookies);
 		const sessionID = JSON.parse(
-			String(sessionCookies["student_session_credentials"]),
+			String(sessionCookies.student_session_credentials),
 		);
 		this.sessionId = sessionID.session_id;
 		await this.getNewSessionId();
@@ -71,7 +71,7 @@ export class StudentClient extends BaseClient {
 	 */
 	async getRewards(): Promise<RewardsResponse> {
 		return await this.makeAuthedRequest(
-			this.API_BASE + "/rewards/" + this.studentId,
+			`${this.API_BASE}/rewards/${this.studentId}`,
 			{
 				method: "GET",
 			},
@@ -84,7 +84,7 @@ export class StudentClient extends BaseClient {
 	 * @returns An object containing the current student's balance and item ID purchased
 	 */
 	async purchaseReward(itemId: number): Promise<RewardPurchaseResponse> {
-		return await this.makeAuthedRequest(this.API_BASE + "/purchase/" + itemId, {
+		return await this.makeAuthedRequest(`${this.API_BASE}/purchase/${itemId}`, {
 			method: "POST",
 			body: `pupil_id=${this.studentId}`,
 		});
@@ -99,7 +99,7 @@ export class StudentClient extends BaseClient {
 	async getStudentCode(
 		options: GetStudentCodeOptions,
 	): Promise<GetStudentCodeResponse> {
-		const data = await this.makeAuthedRequest(this.API_BASE + "/getcode", {
+		const data = await this.makeAuthedRequest(`${this.API_BASE}/getcode`, {
 			method: "POST",
 			body: JSON.stringify({
 				date: options.dateOfBirth,