diff --git a/server/src/controllers/controllerUtils.ts b/server/src/controllers/controllerUtils.ts
index e5c852591..f8447fd59 100755
--- a/server/src/controllers/controllerUtils.ts
+++ b/server/src/controllers/controllerUtils.ts
@@ -1,11 +1,12 @@
 import { AppError } from "@/utils/AppError.js";
-import { type MonitorType, MonitorTypes, UserRole } from "@/types/index.js";
+import { Monitor, type MonitorType, MonitorTypes, UserRole } from "@/types/index.js";
+import sslChecker, { SSLDetails } from "ssl-checker";
+type SSLCheckerType = typeof sslChecker;
 
-const fetchMonitorCertificate = async (sslChecker: any, monitor: any): Promise<any> => {
+const fetchMonitorCertificate = async (checker: SSLCheckerType, monitor: Monitor): Promise<SSLDetails> => {
 	const monitorUrl = new URL(monitor.url);
 	const hostname = monitorUrl.hostname;
-	const cert = await sslChecker(hostname);
-	// Throw an error if no cert or if cert.validTo is not present
+	const cert = await checker(hostname);
 	if (cert?.validTo === null || cert?.validTo === undefined) {
 		throw new Error("Certificate not found");
 	}
diff --git a/server/src/types/ssl-checker.d.ts b/server/src/types/ssl-checker.d.ts
new file mode 100644
index 000000000..bcbc39858
--- /dev/null
+++ b/server/src/types/ssl-checker.d.ts
@@ -0,0 +1,24 @@
+declare module "ssl-checker" {
+	import { Agent } from "https";
+
+	export interface SSLDetails {
+		daysRemaining: number;
+		valid: boolean;
+		validFrom: string;
+		validTo: string;
+		validFor: string[];
+	}
+
+	export interface SSLOptions {
+		method?: "GET" | "HEAD";
+		port?: number;
+		agent?: Agent;
+		rejectUnauthorized?: boolean;
+		validateSubjectAltName?: boolean;
+	}
+
+	function sslChecker(hostname: string, options?: SSLOptions): Promise<SSLDetails>;
+
+	// Change 'export default' to 'export =' to allow it to be callable
+	export = sslChecker;
+}