Bolt + device storage
Users expect an app to remember them. Cookies and localStorage usually keep your Bolt app signed in, but they are web storage and go away with the cache. WebViewGold adds two small native helpers: a persistent value store (writevalue:// and readvalue://) for settings and session restore, and a device UUID (get-uuid://) for device-bound licenses, trusted devices and per-device settings on your server.
From $109 one-time per platform, or let our team do it all from $698.
writevalue:// stores everything after the scheme as one string in the app's private storage; readvalue:// injects it back into the page, as window.storedValues on iOS and window.appSettings on Android. Values survive restarts and cache clears and disappear when the app is uninstalled (on Android also when its app data is wiped).
get-uuid:// sets the JavaScript variable uuid, a non-personal unique device ID. Alternatively append it once to the first request as ?uuid=XYZ (enhanceUrlUUID / UUID_ENHANCE_WEBVIEW_URL) or inject it on every page (autoInjectVariable / AUTO_INJECT_VARIABLES).
Not synced across devices, not a database, not a password vault. Keep values small (settings, flags, a revocable token), keep user data in Supabase, Firebase or your own API, and never treat the UUID as proof of identity.
Paste this into Bolt to implement the web-app side. Review the result, publish, then test inside the WebViewGold app.
Add device-level persistence and a device limit for the WebViewGold app wrapper. Create src/lib/device.ts with isNativeApp() (navigator.userAgent contains my WebViewGold token), saveLocal(values) that navigates to a writevalue:// string such as writevalue://theme=dark;lang=en;onboarded=1, loadLocal() that navigates to readvalue:// and parses window.storedValues or window.appSettings after 250 ms, and getDeviceId() that returns the global uuid (navigating to get-uuid:// first if needed). Outside the app, fall back to localStorage and return null for the device ID. On startup, apply the saved theme and language before showing the dashboard. After login, POST { uuid, platform } to a Netlify Function register-device that uses the Supabase service role key to upsert into a devices table and returns 403 with a clear message if a Pro user already has two other active devices. Add a Manage devices screen to free a slot. Never chain two native schemes in the same tick.
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Write a revocable refresh token after login. If the web session is gone after a cache clear, read it back on launch and restore the session silently instead of showing the login screen.
Theme, language, units, "onboarding done", the last opened workspace: read locally on launch, before your backend answers, and even offline.
"Pro works on two devices": register the UUID on activation, count active devices on the server and offer a Manage devices screen to free a slot.
Skip the second factor or the email code on a device the user already confirmed, and show "Signed in on: iPhone, Pixel" with a sign-out per device.
A front-desk iPad or a warehouse scanner phone that should always open the same location or station: store the station ID per device.
About an hour, plus a devices table in your backend.
Set a custom user agent in Config.swift (useragent_iphone, useragent_ipad) and Config.java (USER_AGENT) and only call the schemes when it matches. In the browser, fall back to localStorage.
Everything after writevalue:// is stored verbatim as one string, so use a simple key=value;key=value format with URL-safe values (letters, digits, dot, dash, underscore). Each write replaces the whole string, so always write all keys.
Navigate to readvalue://, wait a moment (the docs use 200 ms) and parse window.storedValues (iOS) or window.appSettings (Android). Apply theme and language first, then restore the login session if needed.
After login, read uuid (after get-uuid://, or automatically with the auto-inject option) and store it with the user in Supabase, Firebase or your own API: user ID, UUID, platform, last seen. Enforce seat limits on the server, never in the client.
On logout, rewrite the value without the token and revoke it on the server. On account deletion, delete the device rows too (the account deletion guide).
iOS processes only one scheme navigation per script run, so chain calls with short delays (or use multiapicall://, which supports get-uuid) instead of firing them in the same tick.
Same API in the app and in the browser. Replace YourAppToken with your custom user agent.
var inApp = navigator.userAgent.indexOf("YourAppToken") !== -1;
function nativeWrite(values) { // { rt: "abc123", theme: "dark", lang: "en" }
var str = Object.keys(values).map(function (k) { return k + "=" + (values[k] || ""); }).join(";");
if (!inApp) { try { localStorage.setItem("appValues", str); } catch (e) {} return; }
window.location.href = "writevalue://" + str;
}
function parseValues(str) {
var out = {};
String(str || "").split(";").forEach(function (pair) {
var i = pair.indexOf("=");
if (i > 0) out[pair.slice(0, i)] = pair.slice(i + 1);
});
return out;
}
function nativeRead(callback) {
if (!inApp) { callback(parseValues(localStorage.getItem("appValues"))); return; }
window.location.href = "readvalue://";
setTimeout(function () {
callback(parseValues(window.storedValues || window.appSettings)); // iOS || Android
}, 250);
}
function nativeDeviceId(callback) {
if (!inApp) { callback(null); return; }
if (typeof uuid !== "undefined") { callback(uuid); return; } // auto-injected
window.location.href = "get-uuid://";
setTimeout(function () { callback(typeof uuid !== "undefined" ? uuid : null); }, 250);
}Use them first; inside the app they persist the way they do in a browser. The native value store is the backup for what must survive a cache clear, such as a revocable device token, onboarding state or a language choice, and it is available on launch, even offline.
No. It is a non-personal device identifier for your own app logic, not the IDFA or the Android advertising ID, and reading it does not show the App Tracking Transparency prompt. If you used it to track users across other companies' apps or shared it with ad networks, it would become tracking and the ATT rules would apply.
No. Values are per install and per device. Anything that should follow the user (profile, preferences, purchases) belongs in your backend; the device store only speeds up launch and keeps one device signed in.
Stored values are gone after an uninstall, and you should not assume the UUID stays the same either. Let users sign in again, register the device anew, and free old devices in Supabase, Firebase or your own API after a period of inactivity or from a Manage devices screen.
Only the fallback. The schemes work inside the WebViewGold app, not in a desktop browser or a Bolt preview. Detect the custom user agent, use the localStorage fallback in the browser and test the real flow on a phone with a build of the app.
Same result, different amount of work on your side. All three come with the approval guarantee and 24/7 human support.
$109 per platform, one-time
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