diff --git a/apps/dokploy/__test__/wss/listen-deployment.test.ts b/apps/dokploy/__test__/wss/listen-deployment.test.ts
new file mode 100644
index 000000000..947006da2
--- /dev/null
+++ b/apps/dokploy/__test__/wss/listen-deployment.test.ts
@@ -0,0 +1,169 @@
+import { EventEmitter } from "node:events";
+import http from "node:http";
+import type { AddressInfo } from "node:net";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import WebSocket from "ws";
+
+class FakeChild extends EventEmitter {
+	stdout = new EventEmitter();
+	stderr = new EventEmitter();
+	killed = false;
+	exitCode: number | null = null;
+	signalCode: NodeJS.Signals | null = null;
+	signals: string[] = [];
+	// Mirrors ChildProcess: `killed` flips as soon as a signal is delivered,
+	// even if the process ignores it and keeps running.
+	ignoreSigterm = false;
+
+	kill(signal: NodeJS.Signals = "SIGTERM") {
+		this.signals.push(signal);
+		this.killed = true;
+		if (signal === "SIGTERM" && this.ignoreSigterm) return true;
+		this.signalCode = signal;
+		this.emit("close", null, signal);
+		return true;
+	}
+}
+
+const children = vi.hoisted(() => [] as FakeChild[]);
+const nextChild = vi.hoisted(() => ({ ignoreSigterm: false }));
+vi.mock("node:child_process", async (importOriginal) => ({
+	...(await importOriginal<typeof import("node:child_process")>()),
+	spawn: vi.fn(() => {
+		const child = new FakeChild();
+		child.ignoreSigterm = nextChild.ignoreSigterm;
+		children.push(child);
+		return child;
+	}),
+}));
+
+const sshClients = vi.hoisted(
+	() => [] as { connect: ReturnType<typeof vi.fn> }[],
+);
+vi.mock("ssh2", () => ({
+	Client: vi.fn(function (this: Record<string, unknown>) {
+		this.on = vi.fn(() => this);
+		this.connect = vi.fn(() => this);
+		this.end = vi.fn();
+		sshClients.push(this as never);
+	}),
+}));
+
+const mockValidateRequest = vi.hoisted(() => vi.fn());
+const mockFindServerById = vi.hoisted(() => vi.fn());
+vi.mock("@dokploy/server", () => ({
+	IS_CLOUD: false,
+	validateRequest: mockValidateRequest,
+	findServerById: mockFindServerById,
+}));
+vi.mock("@dokploy/server/wss/utils", () => ({
+	readValidDirectory: () => true,
+}));
+
+import { setupDeploymentLogsWebSocketServer } from "@/server/wss/listen-deployment";
+
+const AUTH = {
+	user: { id: "user-1" },
+	session: { activeOrganizationId: "org-1" },
+};
+
+const deferred = <T>() => {
+	let resolve!: (value: T) => void;
+	const promise = new Promise<T>((r) => {
+		resolve = r;
+	});
+	return { promise, resolve };
+};
+
+const flush = () => new Promise((r) => setTimeout(r, 50));
+
+let server: http.Server;
+let url: string;
+
+beforeEach(async () => {
+	children.length = 0;
+	sshClients.length = 0;
+	nextChild.ignoreSigterm = false;
+	vi.clearAllMocks();
+	server = http.createServer();
+	setupDeploymentLogsWebSocketServer(server);
+	await new Promise<void>((r) => server.listen(0, "127.0.0.1", r));
+	const { port } = server.address() as AddressInfo;
+	url = `ws://127.0.0.1:${port}/listen-deployment?logPath=/etc/dokploy/logs/app/deploy.log`;
+});
+
+afterEach(async () => {
+	vi.useRealTimers();
+	await new Promise((r) => server.close(r));
+});
+
+const connect = async (query = "") => {
+	const ws = new WebSocket(`${url}${query}`);
+	await new Promise((r) => ws.once("open", r));
+	return ws;
+};
+
+const closeClient = async (ws: WebSocket) => {
+	ws.close();
+	await new Promise((r) => ws.once("close", r));
+	await flush();
+};
+
+describe("deployment logs websocket (#5518)", () => {
+	it("kills tail when the client disconnects", async () => {
+		mockValidateRequest.mockResolvedValue(AUTH);
+		const ws = await connect();
+		await flush();
+		expect(children).toHaveLength(1);
+
+		await closeClient(ws);
+		expect(children[0]!.signals).toContain("SIGTERM");
+	});
+
+	it("does not spawn tail when the client disconnects during auth", async () => {
+		const auth = deferred<typeof AUTH>();
+		mockValidateRequest.mockReturnValue(auth.promise);
+		const ws = await connect();
+
+		await closeClient(ws);
+		auth.resolve(AUTH);
+		await flush();
+
+		const leaked = children.filter(
+			(c) => c.exitCode === null && c.signalCode === null,
+		);
+		expect(leaked).toHaveLength(0);
+	});
+
+	it("does not open an SSH session when the client disconnects while loading the server", async () => {
+		mockValidateRequest.mockResolvedValue(AUTH);
+		const serverLookup = deferred<unknown>();
+		mockFindServerById.mockReturnValue(serverLookup.promise);
+		const ws = await connect("&serverId=srv-1");
+
+		await closeClient(ws);
+		serverLookup.resolve({
+			organizationId: "org-1",
+			sshKeyId: "key-1",
+			sshKey: { privateKey: "key" },
+			ipAddress: "10.0.0.1",
+			port: 22,
+			username: "root",
+		});
+		await flush();
+
+		const connected = sshClients.filter((c) => c.connect.mock.calls.length > 0);
+		expect(connected).toHaveLength(0);
+	});
+
+	it("force-kills tail with SIGKILL when SIGTERM does not stop it", async () => {
+		nextChild.ignoreSigterm = true;
+		mockValidateRequest.mockResolvedValue(AUTH);
+		const ws = await connect();
+		await flush();
+
+		await closeClient(ws);
+		await new Promise((r) => setTimeout(r, 1100));
+		expect(children[0]!.signals).toEqual(["SIGTERM", "SIGKILL"]);
+	});
+});
diff --git a/apps/dokploy/server/wss/listen-deployment.ts b/apps/dokploy/server/wss/listen-deployment.ts
index d01c4d6d4..96a06c7f3 100644
--- a/apps/dokploy/server/wss/listen-deployment.ts
+++ b/apps/dokploy/server/wss/listen-deployment.ts
@@ -33,6 +33,11 @@ export const setupDeploymentLogsWebSocketServer = (
 		const serverId = url.searchParams.get("serverId");
 		const { user, session } = await validateRequest(req);
 
+		// Client may have disconnected during the await; a later close handler would never fire.
+		if (ws.readyState !== ws.OPEN) {
+			return;
+		}
+
 		// Generate unique connection ID for tracking
 		const connectionId = `deployment-logs-${Date.now()}-${Math.random().toString(36).substring(7)}`;
 		if (!logPath) {
@@ -54,10 +59,33 @@ export const setupDeploymentLogsWebSocketServer = (
 		let tailProcess: ReturnType<typeof spawn> | null = null;
 		let sshClient: Client | null = null;
 
+		// `killed` is set once a signal is sent, not when the process exits.
+		const isTailRunning = () =>
+			tailProcess !== null &&
+			tailProcess.exitCode === null &&
+			tailProcess.signalCode === null;
+
+		const stopTailProcess = () => {
+			if (!isTailRunning()) {
+				return;
+			}
+			tailProcess!.kill("SIGTERM");
+			// Force kill after a timeout if it doesn't terminate
+			setTimeout(() => {
+				if (isTailRunning()) {
+					tailProcess!.kill("SIGKILL");
+				}
+			}, 1000);
+		};
+
 		try {
 			if (serverId) {
 				const server = await findServerById(serverId);
 
+				if (ws.readyState !== ws.OPEN) {
+					return;
+				}
+
 				if (server.organizationId !== session.activeOrganizationId) {
 					ws.close();
 					return;
@@ -155,30 +183,11 @@ export const setupDeploymentLogsWebSocketServer = (
 					}
 				});
 
-				ws.on("close", () => {
-					if (tailProcess && !tailProcess.killed) {
-						tailProcess.kill("SIGTERM");
-						// Force kill after a timeout if it doesn't terminate
-						setTimeout(() => {
-							if (tailProcess && !tailProcess.killed) {
-								tailProcess.kill("SIGKILL");
-							} else {
-							}
-						}, 1000);
-					} else {
-					}
-				});
+				ws.on("close", stopTailProcess);
 			}
 		} catch (error) {
 			// Clean up resources on error
-			if (tailProcess && !tailProcess.killed) {
-				tailProcess.kill("SIGTERM");
-				setTimeout(() => {
-					if (tailProcess && !tailProcess.killed) {
-						tailProcess.kill("SIGKILL");
-					}
-				}, 1000);
-			}
+			stopTailProcess();
 			if (sshClient) {
 				sshClient.end();
 			}