diff --git a/packages/app/src/components/multi-daemon-session-host.tsx b/packages/app/src/components/multi-daemon-session-host.tsx
index a5e97a625..a6b2d9383 100644
--- a/packages/app/src/components/multi-daemon-session-host.tsx
+++ b/packages/app/src/components/multi-daemon-session-host.tsx
@@ -4,7 +4,7 @@ import {
   type HostProfile,
 } from "@/contexts/daemon-registry-context";
 import { useDaemonConnections } from "@/contexts/daemon-connections-context";
-import { buildDaemonWebSocketUrl, buildRelayWebSocketUrl } from "@/utils/daemon-endpoints";
+import { buildDaemonWebSocketUrl, buildRelayWebSocketUrl, extractHostPortFromWebSocketUrl } from "@/utils/daemon-endpoints";
 import { useEffect, useMemo, useRef, useState } from "react";
 
 function buildCandidateUrls(daemon: HostProfile): string[] {
@@ -41,18 +41,6 @@ function buildCandidateUrls(daemon: HostProfile): string[] {
   return out;
 }
 
-function extractEndpointFromUrl(url: string): string | null {
-  try {
-    const parsed = new URL(url);
-    const host = parsed.hostname;
-    const port = parsed.port ? Number(parsed.port) : parsed.protocol === "wss:" ? 443 : 80;
-    const isIpv6 = host.includes(":") && !host.startsWith("[") && !host.endsWith("]");
-    return isIpv6 ? `[${host}]:${port}` : `${host}:${port}`;
-  } catch {
-    return null;
-  }
-}
-
 function ManagedDaemonSession({ daemon }: { daemon: HostProfile }) {
   const { connectionStates } = useDaemonConnections();
   const { updateDaemon } = useDaemonRegistry();
@@ -87,9 +75,15 @@ function ManagedDaemonSession({ daemon }: { daemon: HostProfile }) {
   useEffect(() => {
     if (!connection) return;
 
-    if (status === "online") {
-      if (pendingMetadataWriteRef.current) return;
-      const endpoint = extractEndpointFromUrl(activeUrl);
+      if (status === "online") {
+        if (pendingMetadataWriteRef.current) return;
+      const endpoint = (() => {
+        try {
+          return extractHostPortFromWebSocketUrl(activeUrl);
+        } catch {
+          return null;
+        }
+      })();
       if (!endpoint) return;
       if (daemon.metadata?.lastKnownGoodEndpoint === endpoint) return;
 
diff --git a/packages/app/src/utils/daemon-endpoints.ts b/packages/app/src/utils/daemon-endpoints.ts
index 34f134b40..f3885b5b8 100644
--- a/packages/app/src/utils/daemon-endpoints.ts
+++ b/packages/app/src/utils/daemon-endpoints.ts
@@ -1,9 +1,22 @@
 import { Buffer } from "buffer";
+import {
+  buildDaemonWebSocketUrl,
+  buildRelayWebSocketUrl as buildSharedRelayWebSocketUrl,
+  deriveLabelFromEndpoint,
+  extractHostPortFromWebSocketUrl,
+  normalizeHostPort,
+  parseHostPort,
+  type HostPortParts,
+} from "@server/shared/daemon-endpoints";
 
-export type HostPortParts = {
-  host: string;
-  port: number;
-  isIpv6: boolean;
+export type { HostPortParts };
+
+export {
+  buildDaemonWebSocketUrl,
+  deriveLabelFromEndpoint,
+  extractHostPortFromWebSocketUrl,
+  normalizeHostPort,
+  parseHostPort,
 };
 
 function decodeBase64UrlToUtf8(input: string): string {
@@ -17,98 +30,6 @@ export function decodeOfferFragmentPayload(encoded: string): unknown {
   return JSON.parse(json) as unknown;
 }
 
-export function parseHostPort(input: string): HostPortParts {
-  const trimmed = input.trim();
-  if (!trimmed) {
-    throw new Error("Host is required");
-  }
-
-  // IPv6: [::1]:6767
-  if (trimmed.startsWith("[")) {
-    const match = trimmed.match(/^\[([^\]]+)\]:(\d{1,5})$/);
-    if (!match) {
-      throw new Error("Invalid host:port (expected [::1]:6767)");
-    }
-    const host = match[1].trim();
-    const port = Number(match[2]);
-    if (!host) throw new Error("Host is required");
-    if (!Number.isInteger(port) || port < 1 || port > 65535) {
-      throw new Error("Port must be between 1 and 65535");
-    }
-    return { host, port, isIpv6: true };
-  }
-
-  const match = trimmed.match(/^(.+):(\d{1,5})$/);
-  if (!match) {
-    throw new Error("Invalid host:port (expected localhost:6767)");
-  }
-  const host = match[1].trim();
-  const port = Number(match[2]);
-  if (!host) throw new Error("Host is required");
-  if (!Number.isInteger(port) || port < 1 || port > 65535) {
-    throw new Error("Port must be between 1 and 65535");
-  }
-  return { host, port, isIpv6: false };
-}
-
-export function normalizeHostPort(input: string): string {
-  const { host, port, isIpv6 } = parseHostPort(input);
-  if (isIpv6) {
-    return `[${host}]:${port}`;
-  }
-  return `${host}:${port}`;
-}
-
-export function extractHostPortFromWebSocketUrl(wsUrl: string): string {
-  const parsed = new URL(wsUrl);
-  if (parsed.protocol !== "ws:" && parsed.protocol !== "wss:") {
-    throw new Error("Invalid WebSocket URL protocol");
-  }
-  if (parsed.pathname.replace(/\/+$/, "") !== "/ws") {
-    throw new Error("Invalid WebSocket URL (expected /ws path)");
-  }
-
-  const host = parsed.hostname;
-  const port = parsed.port ? Number(parsed.port) : parsed.protocol === "wss:" ? 443 : 80;
-  if (!host) {
-    throw new Error("Invalid WebSocket URL (missing hostname)");
-  }
-  if (!Number.isInteger(port) || port < 1 || port > 65535) {
-    throw new Error("Invalid WebSocket URL (invalid port)");
-  }
-
-  const isIpv6 = host.includes(":") && !host.startsWith("[") && !host.endsWith("]");
-  const hostPort = isIpv6 ? `[${host}]:${port}` : `${host}:${port}`;
-  return hostPort;
-}
-
-function shouldUseSecureWebSocket(port: number): boolean {
-  return port === 443;
-}
-
-export function buildDaemonWebSocketUrl(endpoint: string): string {
-  const { host, port, isIpv6 } = parseHostPort(endpoint);
-  const protocol = shouldUseSecureWebSocket(port) ? "wss" : "ws";
-  const hostPart = isIpv6 ? `[${host}]` : host;
-  return `${protocol}://${hostPart}:${port}/ws`;
-}
-
 export function buildRelayWebSocketUrl(params: { endpoint: string; sessionId: string }): string {
-  const { host, port, isIpv6 } = parseHostPort(params.endpoint);
-  const protocol = shouldUseSecureWebSocket(port) ? "wss" : "ws";
-  const hostPart = isIpv6 ? `[${host}]` : host;
-  const url = new URL(`${protocol}://${hostPart}:${port}/ws`);
-  url.searchParams.set("session", params.sessionId);
-  url.searchParams.set("role", "client");
-  return url.toString();
+  return buildSharedRelayWebSocketUrl({ ...params, role: "client" });
 }
-
-export function deriveLabelFromEndpoint(endpoint: string): string {
-  try {
-    const { host } = parseHostPort(endpoint);
-    return host || "Unnamed Host";
-  } catch {
-    return "Unnamed Host";
-  }
-}
-
diff --git a/packages/server/src/client/daemon-client-v2.ts b/packages/server/src/client/daemon-client-v2.ts
index fab6edbd2..0e82bb815 100644
--- a/packages/server/src/client/daemon-client-v2.ts
+++ b/packages/server/src/client/daemon-client-v2.ts
@@ -58,6 +58,7 @@ import {
   type EncryptedChannel,
   type Transport as RelayTransport,
 } from "@paseo/relay/e2ee";
+import { isRelayClientWebSocketUrl } from "../shared/daemon-endpoints.js";
 
 export interface Logger {
   debug(obj: object, msg?: string): void;
@@ -2359,18 +2360,6 @@ function createRelayE2eeTransportFactory(
   };
 }
 
-function isRelayClientWebSocketUrl(url: string): boolean {
-  try {
-    const parsed = new URL(url);
-    return (
-      parsed.searchParams.get("role") === "client" &&
-      parsed.searchParams.has("session")
-    );
-  } catch {
-    return false;
-  }
-}
-
 function createEncryptedTransport(
   base: DaemonTransport,
   daemonPublicKeyB64: string,
diff --git a/packages/server/src/server/relay-transport.ts b/packages/server/src/server/relay-transport.ts
index 3a33d8219..ca8c22093 100644
--- a/packages/server/src/server/relay-transport.ts
+++ b/packages/server/src/server/relay-transport.ts
@@ -7,6 +7,7 @@ import {
   type EncryptedChannel,
   type Transport as RelayTransport,
 } from "@paseo/relay/e2ee";
+import { buildRelayWebSocketUrl } from "../shared/daemon-endpoints.js";
 
 type RelayTransportOptions = {
   logger: pino.Logger;
@@ -61,7 +62,11 @@ export function startRelayTransport({
   const connect = (): void => {
     if (stopped) return;
 
-    const url = buildRelayWebSocketUrl(relayEndpoint, sessionId, "server");
+    const url = buildRelayWebSocketUrl({
+      endpoint: relayEndpoint,
+      sessionId,
+      role: "server",
+    });
     const socket = new WebSocket(url);
     ws = socket;
 
@@ -247,46 +252,4 @@ function bufferFromWsData(data: unknown): Buffer | null {
   return null;
 }
 
-function buildRelayWebSocketUrl(
-  relayEndpoint: string,
-  sessionId: string,
-  role: "server" | "client"
-): string {
-  const { host, port } = parseHostPort(relayEndpoint);
-  const protocol = port === 443 ? "wss" : "ws";
-  return `${protocol}://${host}:${port}/ws?session=${encodeURIComponent(
-    sessionId
-  )}&role=${role}`;
-}
-
-function parseHostPort(input: string): { host: string; port: number } {
-  const trimmed = input.trim();
-
-  if (trimmed.startsWith("[")) {
-    const endIdx = trimmed.indexOf("]");
-    if (endIdx === -1) {
-      throw new Error(`Invalid relay endpoint: ${input}`);
-    }
-    const host = trimmed.slice(1, endIdx);
-    const rest = trimmed.slice(endIdx + 1);
-    if (!rest.startsWith(":")) {
-      throw new Error(`Invalid relay endpoint: ${input}`);
-    }
-    const port = Number.parseInt(rest.slice(1), 10);
-    if (!Number.isFinite(port)) {
-      throw new Error(`Invalid relay port: ${input}`);
-    }
-    return { host: `[${host}]`, port };
-  }
-
-  const idx = trimmed.lastIndexOf(":");
-  if (idx === -1) {
-    throw new Error(`Invalid relay endpoint (expected host:port): ${input}`);
-  }
-  const host = trimmed.slice(0, idx);
-  const port = Number.parseInt(trimmed.slice(idx + 1), 10);
-  if (!host || !Number.isFinite(port)) {
-    throw new Error(`Invalid relay endpoint: ${input}`);
-  }
-  return { host, port };
-}
+// buildRelayWebSocketUrl + parseHostPort live in ../shared/daemon-endpoints.ts
diff --git a/packages/server/src/shared/connection-offer.ts b/packages/server/src/shared/connection-offer.ts
index 37be5c9bb..a21d3e4ef 100644
--- a/packages/server/src/shared/connection-offer.ts
+++ b/packages/server/src/shared/connection-offer.ts
@@ -14,4 +14,3 @@ export const ConnectionOfferV1Schema = z.object({
 });
 
 export type ConnectionOfferV1 = z.infer<typeof ConnectionOfferV1Schema>;
-
diff --git a/packages/server/src/shared/daemon-endpoints.ts b/packages/server/src/shared/daemon-endpoints.ts
new file mode 100644
index 000000000..7eb50dbe0
--- /dev/null
+++ b/packages/server/src/shared/daemon-endpoints.ts
@@ -0,0 +1,117 @@
+export type HostPortParts = {
+  host: string;
+  port: number;
+  isIpv6: boolean;
+};
+
+export type RelayRole = "server" | "client";
+
+function parsePort(portStr: string, context: string): number {
+  const port = Number(portStr);
+  if (!Number.isInteger(port) || port < 1 || port > 65535) {
+    throw new Error(`${context}: port must be between 1 and 65535`);
+  }
+  return port;
+}
+
+export function parseHostPort(input: string): HostPortParts {
+  const trimmed = input.trim();
+  if (!trimmed) {
+    throw new Error("Host is required");
+  }
+
+  // IPv6: [::1]:6767
+  if (trimmed.startsWith("[")) {
+    const match = trimmed.match(/^\[([^\]]+)\]:(\d{1,5})$/);
+    if (!match) {
+      throw new Error("Invalid host:port (expected [::1]:6767)");
+    }
+    const host = match[1].trim();
+    if (!host) throw new Error("Host is required");
+    const port = parsePort(match[2], "Invalid host:port");
+    return { host, port, isIpv6: true };
+  }
+
+  const match = trimmed.match(/^(.+):(\d{1,5})$/);
+  if (!match) {
+    throw new Error("Invalid host:port (expected localhost:6767)");
+  }
+  const host = match[1].trim();
+  if (!host) throw new Error("Host is required");
+  const port = parsePort(match[2], "Invalid host:port");
+  return { host, port, isIpv6: false };
+}
+
+export function normalizeHostPort(input: string): string {
+  const { host, port, isIpv6 } = parseHostPort(input);
+  return isIpv6 ? `[${host}]:${port}` : `${host}:${port}`;
+}
+
+export function deriveLabelFromEndpoint(endpoint: string): string {
+  try {
+    const { host } = parseHostPort(endpoint);
+    return host || "Unnamed Host";
+  } catch {
+    return "Unnamed Host";
+  }
+}
+
+function shouldUseSecureWebSocket(port: number): boolean {
+  return port === 443;
+}
+
+export function buildDaemonWebSocketUrl(endpoint: string): string {
+  const { host, port, isIpv6 } = parseHostPort(endpoint);
+  const protocol = shouldUseSecureWebSocket(port) ? "wss" : "ws";
+  const hostPart = isIpv6 ? `[${host}]` : host;
+  return `${protocol}://${hostPart}:${port}/ws`;
+}
+
+export function buildRelayWebSocketUrl(params: {
+  endpoint: string;
+  sessionId: string;
+  role: RelayRole;
+}): string {
+  const { host, port, isIpv6 } = parseHostPort(params.endpoint);
+  const protocol = shouldUseSecureWebSocket(port) ? "wss" : "ws";
+  const hostPart = isIpv6 ? `[${host}]` : host;
+  const url = new URL(`${protocol}://${hostPart}:${port}/ws`);
+  url.searchParams.set("session", params.sessionId);
+  url.searchParams.set("role", params.role);
+  return url.toString();
+}
+
+export function extractHostPortFromWebSocketUrl(wsUrl: string): string {
+  const parsed = new URL(wsUrl);
+  if (parsed.protocol !== "ws:" && parsed.protocol !== "wss:") {
+    throw new Error("Invalid WebSocket URL protocol");
+  }
+  if (parsed.pathname.replace(/\/+$/, "") !== "/ws") {
+    throw new Error("Invalid WebSocket URL (expected /ws path)");
+  }
+
+  const host = parsed.hostname;
+  const port = parsed.port ? Number(parsed.port) : parsed.protocol === "wss:" ? 443 : 80;
+  if (!host) {
+    throw new Error("Invalid WebSocket URL (missing hostname)");
+  }
+  if (!Number.isInteger(port) || port < 1 || port > 65535) {
+    throw new Error("Invalid WebSocket URL (invalid port)");
+  }
+
+  const isIpv6 = host.includes(":") && !host.startsWith("[") && !host.endsWith("]");
+  return isIpv6 ? `[${host}]:${port}` : `${host}:${port}`;
+}
+
+export function isRelayClientWebSocketUrl(url: string): boolean {
+  try {
+    const parsed = new URL(url);
+    return (
+      parsed.searchParams.get("role") === "client" &&
+      parsed.searchParams.has("session")
+    );
+  } catch {
+    return false;
+  }
+}
+