What is a web-to-app script?

What it does

The script runs on a mobile web page, works out whether the visitor has the app, and acts accordingly: deep link them into the matching in-app content if they do, or offer the app store if they do not.

Done properly it also carries the destination through an install, so a new user who downloads arrives at the content they were looking at rather than at a home screen.

The conversion cost of doing it badly

This is where most implementations lose money without anyone measuring it.

Interrupting a user who was about to complete a purchase on the web, in order to push an install, trades a likely conversion now for an uncertain one later. On high-intent pages the trade is frequently a loss, and the install count makes it look like a win.

The other common failure is losing the destination. A user reading a specific product page who is routed to a generic app home screen has been given more friction, not less — and the whole point of the mechanism was to remove friction.

Doing it well

• Only where the app is genuinely better, not on every page by default.
• Never mid-checkout. The web conversion in progress is worth more than the install.
• Preserve the destination, including through an install.
• Make it dismissible and remember the dismissal.
• Measure against the web conversion displaced, not only the installs produced — see smart banners.