diff --git a/shared/components/rstack-identity.ts b/shared/components/rstack-identity.ts
index 7c082c0..c04ec68 100644
--- a/shared/components/rstack-identity.ts
+++ b/shared/components/rstack-identity.ts
@@ -810,8 +810,8 @@ export class RStackIdentity extends HTMLElement {
 				this.#render();
 		this.dispatchEvent(new CustomEvent("auth-change", { bubbles: true, composed: true }));
 				callbacks?.onSuccess?.();
-				// Auto-redirect to personal space
-				autoResolveSpace(data.token, username);
+				// Show post-signup prompt recommending second device before redirecting
+				this.#showPostSignupPrompt(data.token, username);
 			} catch (err: any) {
 				btn.disabled = false;
 				btn.innerHTML = "🔐 Create Passkey";
@@ -861,6 +861,123 @@ export class RStackIdentity extends HTMLElement {
 		}
 	}
 
+	// ── Post-signup onboarding prompt ──
+
+	#showPostSignupPrompt(token: string, username: string): void {
+		const overlay = document.createElement("div");
+		overlay.className = "rstack-auth-overlay";
+
+		const goToSpace = () => {
+			overlay.remove();
+			autoResolveSpace(token, username);
+		};
+
+		let step: "welcome" | "linking" | "done" = "welcome";
+		let linkUrl = "";
+
+		const render = () => {
+			if (step === "welcome") {
+				const qrHint = /Mobi|Android|iPhone|iPad/i.test(navigator.userAgent)
+					? "You can link your laptop or another phone."
+					: "Grab your phone or tablet and scan the code.";
+				overlay.innerHTML = `
+					<style>${MODAL_STYLES}${ONBOARDING_STYLES}</style>
+					<div class="auth-modal onboarding-modal">
+						<h2>Welcome to rSpace!</h2>
+						<p style="margin-bottom:0.75rem">Your account <strong>${username}</strong> is ready.</p>
+
+						<div class="onboarding-card onboarding-card--primary">
+							<div class="onboarding-card-icon">📱</div>
+							<div class="onboarding-card-content">
+								<div class="onboarding-card-title">Link a Second Device</div>
+								<div class="onboarding-card-desc">
+									Add a passkey on your phone or tablet so you can sign in from anywhere.
+									This also serves as a backup if you lose access to this device.
+								</div>
+								<div class="onboarding-card-hint">${qrHint}</div>
+							</div>
+						</div>
+						<button class="btn btn--primary" style="width:100%;margin-top:0.75rem" data-action="link-device">📱 Link Another Device</button>
+
+						<button class="btn btn--outline" style="width:100%;margin-top:0.5rem" data-action="skip">Continue to my space</button>
+						<p class="onboarding-later-hint">You can always link devices later from My Account.</p>
+					</div>`;
+			} else if (step === "linking") {
+				const qrSrc = `https://api.qrserver.com/v1/create-qr-code/?size=200x200&data=${encodeURIComponent(linkUrl)}&format=png&margin=8`;
+				overlay.innerHTML = `
+					<style>${MODAL_STYLES}${ONBOARDING_STYLES}</style>
+					<div class="auth-modal onboarding-modal">
+						<h2>Link Another Device</h2>
+						<p style="margin-bottom:0.5rem">Scan this QR code on your phone or tablet to add a passkey.</p>
+						<div class="qr-container">
+							<img src="${qrSrc}" width="200" height="200" alt="QR Code" style="border-radius:12px;background:#fff;padding:4px" />
+						</div>
+						<div class="link-copy-row">
+							<input class="input" id="onboarding-link-url" type="text" readonly value="${linkUrl}" style="font-size:0.8rem;margin-bottom:0" />
+							<button class="btn btn--secondary btn--small" data-action="copy-link" style="flex:none;white-space:nowrap">Copy</button>
+						</div>
+						<p class="onboarding-expire-hint">Link expires in 10 minutes</p>
+						<div class="actions" style="margin-top:1rem">
+							<button class="btn btn--secondary" data-action="back">Back</button>
+							<button class="btn btn--primary" data-action="done">Continue to my space</button>
+						</div>
+					</div>`;
+			} else {
+				overlay.innerHTML = `
+					<style>${MODAL_STYLES}${ONBOARDING_STYLES}</style>
+					<div class="auth-modal onboarding-modal">
+						<div style="font-size:2.5rem;margin-bottom:0.5rem">✅</div>
+						<h2>Device Linked!</h2>
+						<p>You can now sign in from your other device too.</p>
+						<button class="btn btn--primary" style="width:100%;margin-top:1rem" data-action="done">Continue to my space</button>
+					</div>`;
+			}
+			attachListeners();
+		};
+
+		const attachListeners = () => {
+			overlay.querySelector('[data-action="skip"]')?.addEventListener("click", goToSpace);
+			overlay.querySelector('[data-action="done"]')?.addEventListener("click", goToSpace);
+			overlay.querySelector('[data-action="back"]')?.addEventListener("click", () => {
+				step = "welcome";
+				render();
+			});
+			overlay.querySelector('[data-action="copy-link"]')?.addEventListener("click", () => {
+				const input = overlay.querySelector("#onboarding-link-url") as HTMLInputElement;
+				navigator.clipboard.writeText(input.value).catch(() => {});
+				const btn = overlay.querySelector('[data-action="copy-link"]') as HTMLButtonElement;
+				btn.textContent = "Copied!";
+				setTimeout(() => { btn.textContent = "Copy"; }, 2000);
+			});
+			overlay.querySelector('[data-action="link-device"]')?.addEventListener("click", async () => {
+				const btn = overlay.querySelector('[data-action="link-device"]') as HTMLButtonElement;
+				btn.disabled = true;
+				btn.innerHTML = '<span class="spinner"></span> Generating link...';
+				try {
+					const res = await fetch(`${ENCRYPTID_URL}/api/device-link/start`, {
+						method: "POST",
+						headers: { Authorization: `Bearer ${getAccessToken()}` },
+					});
+					const data = await res.json();
+					if (!res.ok || data.error) throw new Error(data.error || "Failed to generate link");
+					linkUrl = data.linkUrl;
+					step = "linking";
+					render();
+				} catch (e: any) {
+					btn.disabled = false;
+					btn.innerHTML = "📱 Link Another Device";
+					const errEl = document.createElement("div");
+					errEl.className = "error";
+					errEl.textContent = e.message;
+					btn.parentElement?.appendChild(errEl);
+				}
+			});
+		};
+
+		document.body.appendChild(overlay);
+		render();
+	}
+
 	// ── Account modal (consolidated) ──
 
 	showAccountModal(): void {
@@ -2100,6 +2217,38 @@ const ACCOUNT_MODAL_STYLES = `
 }
 `;
 
+const ONBOARDING_STYLES = `
+.onboarding-modal { max-width: 440px; }
+.onboarding-card {
+  border: 1px solid var(--rs-border); border-radius: 12px;
+  padding: 1rem 1.25rem; display: flex; gap: 1rem; align-items: flex-start;
+  text-align: left; margin-top: 0.75rem; transition: border-color 0.2s;
+}
+.onboarding-card--primary {
+  border-color: rgba(6,182,212,0.4);
+  background: linear-gradient(135deg, rgba(6,182,212,0.06), rgba(124,58,237,0.06));
+}
+.onboarding-card-icon { font-size: 2rem; flex-shrink: 0; margin-top: 2px; }
+.onboarding-card-content { flex: 1; min-width: 0; }
+.onboarding-card-title {
+  font-size: 1rem; font-weight: 600; color: var(--rs-text-primary); margin-bottom: 4px;
+}
+.onboarding-card-desc {
+  font-size: 0.85rem; color: var(--rs-text-secondary); line-height: 1.5;
+}
+.onboarding-card-hint {
+  font-size: 0.8rem; color: #06b6d4; margin-top: 6px; font-weight: 500;
+}
+.onboarding-later-hint {
+  font-size: 0.75rem; color: var(--rs-text-muted); margin-top: 0.5rem;
+}
+.qr-container { text-align: center; margin: 0.75rem 0; }
+.link-copy-row { display: flex; gap: 8px; align-items: stretch; }
+.onboarding-expire-hint {
+  font-size: 0.75rem; color: var(--rs-text-muted); text-align: center; margin-top: 0.5rem;
+}
+`;
+
 const SPACES_STYLES = `
 .rstack-spaces-overlay {
   position: fixed; inset: 0; background: rgba(0,0,0,0.6);