Web-to-app handoff

In a web-to-app funnel, a visitor arrives from an ad, signs up and often pays on your website, then installs your app. Voidhash keeps them one person across both: the campaign, the Stripe purchase and their app activity belong together, and access bought on the web works in the app. The handoff is your user ID, passed to identify() on both sides.

await voidhash.identify("user_123", { email: "ada@example.com" });

await stripe.checkout.sessions.create({
  metadata: { voidhash_distinct_id: "user_123" },
  subscription_data: { metadata: { voidhash_distinct_id: "user_123" } },
  // ...
});

await voidhash.client.identify("user_123");

The order does not matter: if a user signs up in the app first, the website's anonymous visitor is merged into that user when identify() runs.

Make the app sign-in effortless

Any sign-in that ends with identify() and the same user ID completes the handoff. To keep drop-off low:

• Ask for the email address early in the web funnel and use it as the app login.
• After the web purchase, show a download page with a one-time login link or code from your backend.
• Identify in the app right after sign-in, before checking access, so purchased perks are there on the first screen.

Credit Android installs to the campaign

A Google Play link can carry the visitor's latest campaign, so the Android SDK credits the install to it. Build the link with playStoreUrl() when the visitor follows it:

downloadButton.addEventListener("click", () => {
  window.location.href = voidhash.playStoreUrl("com.example.app");
});

The link's referrer holds the latest touch's utm_* parameters, click IDs, campaign_id, adset_id and ad_id, plus the click time as touch_at. The Android SDK reads them after install with the same rules as the web, and the click time keeps an old click from looking new. Without analytics consent, without a touch, or before initialize() resolves, it returns the plain link.

What a store link does not do

• It carries no identity. No anonymous or user ID is ever put in a link, as a shared link must not hand someone's purchases to another person. The install stays a separate person until the user signs in.
• The App Store has no referrer. On iOS, sign-in is the only handoff.

Next steps

• Identify users
• Stripe revenue
• People and identity