diff --git a/backend/pkg/db/events/events.go b/backend/pkg/db/events/events.go
index 835903b..28d6a54 100644
--- a/backend/pkg/db/events/events.go
+++ b/backend/pkg/db/events/events.go
@@ -266,3 +266,10 @@ func User(userName string) ([]EventWithAssignment, error) {
 		return nil, nil
 	}
 }
+
+// set the availability of an user for a specific event
+func UserAvailability(userName string, eventID, availabilityID int) error {
+	_, err := db.DB.Exec("INSERT INTO USER_AVAILABILITIES (userName, eventID, availabilityID) VALUES ($1, $2, $3) ON CONFLICT (userName, eventID) DO UPDATE SET availabilityID = $3", userName, eventID, availabilityID)
+
+	return err
+}
diff --git a/backend/pkg/router/events.go b/backend/pkg/router/events.go
index 0709b0d..51c9912 100644
--- a/backend/pkg/router/events.go
+++ b/backend/pkg/router/events.go
@@ -1,6 +1,8 @@
 package router
 
 import (
+	"strconv"
+
 	"github.com/gofiber/fiber/v2"
 	"github.com/johannesbuehl/golunteer/backend/pkg/db/events"
 )
@@ -119,6 +121,32 @@ func (a *Handler) getEventsUserAssigned() {
 	}
 }
 
+func (a *Handler) putEventUserAvailability() {
+	// parse the query
+	if eventID := a.C.QueryInt("eventID", -1); eventID == -1 {
+		a.Status = fiber.StatusBadRequest
+
+		logger.Log().Msg("setting user-event-availability failed: query is missing \"eventID\"")
+	} else {
+		// parse the body
+		body := a.C.Body()
+
+		if availabilityID, err := strconv.Atoi(string(body)); err != nil {
+			a.Status = fiber.StatusBadRequest
+
+			logger.Log().Msgf("setting user-event-availability failed: can't get parse: %v", err)
+
+			// insert the availability into the database
+		} else if err := events.UserAvailability(a.UserName, eventID, availabilityID); err != nil {
+			a.Status = fiber.StatusInternalServerError
+
+			logger.Error().Msgf("setting user-event-availability failed: can't write availability to database: %v", err)
+		}
+	}
+
+	// parse the body
+}
+
 func (a *Handler) deleteEvent() {
 	// check for admin
 	if !a.Admin {
diff --git a/backend/pkg/router/router.go b/backend/pkg/router/router.go
index 1a67414..00c8820 100644
--- a/backend/pkg/router/router.go
+++ b/backend/pkg/router/router.go
@@ -107,7 +107,8 @@ func init() {
 			"tasks":          (*Handler).patchTask,          // modify a task
 		},
 		"PUT": {
-			"users/password": (*Handler).putPassword, // change the password
+			"users/password":           (*Handler).putPassword,              // change the password
+			"events/user/availability": (*Handler).putEventUserAvailability, // set or change the users availability for a specific event
 		},
 		"DELETE": {
 			"event":          (*Handler).deleteEvent,        // remove an event
diff --git a/client/src/app/PendingEvents.tsx b/client/src/app/PendingEvents.tsx
index ceaf47e..504b40d 100644
--- a/client/src/app/PendingEvents.tsx
+++ b/client/src/app/PendingEvents.tsx
@@ -41,6 +41,15 @@ export default function PengingEvents() {
 		},
 	});
 
+	async function setAvailability(eventID: number, availabilityID: number) {
+		await apiCall(
+			"PUT",
+			"events/user/availability",
+			{ eventID },
+			availabilityID,
+		);
+	}
+
 	return (
 		<div className="flex justify-center gap-4">
 			{events.items.map((e) => (
@@ -60,6 +69,9 @@ export default function PengingEvents() {
 								)}
 							</div>
 						)}
+						onSelectionChange={(a) =>
+							setAvailability(e.eventID, parseInt(a.anchorKey ?? ""))
+						}
 					>
 						{(availability) => (
 							<SelectItem
diff --git a/client/src/lib.ts b/client/src/lib.ts
index 61b8b11..8becee2 100644
--- a/client/src/lib.ts
+++ b/client/src/lib.ts
@@ -6,6 +6,8 @@ export type AllString<T> = { [K in keyof T]: string };
 
 type QueryParams = Record<string, string | { toString(): string }>;
 
+type Body = object | string | number | boolean;
+
 export type APICallResult<T> = Omit<Response, "json"> & {
 	json: () => Promise<T>;
 };
@@ -19,19 +21,19 @@ export async function apiCall<K>(
 	method: "POST" | "PATCH" | "PUT",
 	api: string,
 	query?: QueryParams,
-	body?: object,
+	body?: Body,
 ): Promise<APICallResult<K>>;
 export async function apiCall<K>(
 	method: "DELETE",
 	api: string,
 	query?: QueryParams,
-	body?: object,
+	body?: Body,
 ): Promise<APICallResult<K>>;
 export async function apiCall<K>(
 	method: "GET" | "POST" | "PATCH" | "PUT" | "DELETE",
 	api: string,
 	query?: QueryParams,
-	body?: object,
+	body?: Body,
 ): Promise<APICallResult<K>> {
 	let url = window.origin + "/api/" + api;
 
@@ -53,7 +55,7 @@ export async function apiCall<K>(
 
 	const response = await fetch(url, {
 		headers: {
-			"Content-Type": "application/json; charset=UTF-8",
+			"Content-Type": `${getContentType(typeof body)}; charset=UTF-8`,
 		},
 		credentials: "include",
 		method,
@@ -63,6 +65,20 @@ export async function apiCall<K>(
 	return response;
 }
 
+function getContentType(type: string): string {
+	switch (type) {
+		case "object":
+			return "application/json";
+		case "string":
+		case "number":
+		case "bigint":
+		case "boolean":
+			return "text/plain";
+		default:
+			return "application/octet-stream";
+	}
+}
+
 export function classNames(classNames: Record<string, boolean>): string {
 	return Object.entries(classNames)
 		.map(([classString, value]) => {