# Turn a server-rendered site into an installable app (PWA) with native push > synsema init --pwa gives any Synsema site a manifest, a service worker, icons and Web Push. It installs on Android, iOS and desktop with a home-screen icon and full screen — nothing native, no store. Published 2026-09-02 · https://synsema.org/blog/installable-app-pwa-native-push An installable web app needs three things a normal site does not have: a manifest, a service worker and a few lines in ``. Synsema scaffolds all of it, and the push notifications on top, so a site that renders on the server becomes an app on the phone without a native client. ## Scaffold it ```sh synsema init myapp --pwa && cd myapp synsema serve app.syn ``` You get `public/manifest.webmanifest`, `public/sw.js` (caches the shell, never `/api/`, never a failed response), `public/app.js` (registers the worker, shows the install button, subscribes to push), an SVG icon with the PNG sizes generated from it, the API in `api.syn` (an `export routes` group with the push routes and their per-route rate limits, mounted by `app.syn` — since 0.6.19), and a one-off `push_keys.syn` that prints your VAPID key pair for `.env`. The server side is the `serve` you already know: ```synsema require serve(8080) require file.read("index.html") serve on 8080 static "/" from "./public" cache "1h" -- sw.js must live at /sw.js (scope "/") route "GET /" give render("index.html", {"title": "My app"}) ``` `.webmanifest` is served as `application/manifest+json`, which is what makes browsers accept it. ## Push, end to end The page reads the public key from `GET /api/push/config`, subscribes, and posts the subscription to `POST /api/push/subscribe`. Sending is one builtin: ```synsema let r be push_send(sub, {"title": "Order shipped", "body": "Arrives Tuesday"}, {"vapid": keys}) when r["gone"] forget_subscription(sub) -- 404/410: the browser dropped it ``` Declare one `require net(...)` per push service you deliver to (FCM, Windows, Mozilla, Apple), and keep the send behind `requires auth` or inside a cron — never in a public route. ## Where it installs Android and desktop Chromium show the install prompt; iOS installs from *Share → Add to Home Screen* and gets push once installed, on a trusted certificate. That last part is one flag — see [Automatic HTTPS in one flag](/blog/automatic-https-lets-encrypt-one-flag). Firefox has no install or app mode: there the site works as a site. ## And on the desktop, as a real app The same files are a desktop app: `synsema init --desktop` adds `desk.syn`, which serves the same page and the same `api.syn` on `127.0.0.1`, opens it as an app window of the browser already on the machine and quits when the last window closes. `synsema build desk.syn -o desk --serve --no-console --icon public/icon.svg` makes it a `.exe` with your icon (a `.app` on macOS, a launcher folder on Linux with `--bundle`). How it works, and what each OS does with it, is in [Ship your web app as a desktop app](/blog/desktop-app-one-binary-browser-window). **Already have a site?** Run `synsema init --pwa` inside it: nothing of yours is overwritten, the factory files land beside yours. Details and the iOS notes are in the [docs](https://synsema.dev/en/0.6.x/41b-pwa), and you can try the language first at [try.synsema.org](https://try.synsema.org).