After a user invites their contacts from within my app, I want to send the first user a notification "so and so installed the app, you can now connect with them."

So when a user invites someone, I send the invitee a link to my landing page, with a unique ID param in the url. Then I know which user got them this far.

The problem is, they ultimately still need to go from my page to the app store to finally download the app.

Once they've successfully installed, how can I track that back to the inviter? Can I do something similar with the url on the app store?

The best I can think of is to have a newly installed app send a timestamp to my server, and then find the closest timestamp from my landing page, and assume they are the same user. But seems like that could also lead me to connect the wrong users.

Is there any better way?

1 Answer 1


The timestamp might be a bad idea:

  • some people may install the app immediately,
  • but quite a few will take some time to reflect, hesitate, and come back later without going again through your page, so that timestamp will not match with the right user
  • finally, some will download your app directly from the store without being invited, again with a timestamp mismatch

If you then connect users on the base of the wrongly determined match, your application will suffer from being considered as unreliable, and it could even be considered as infringing data protection laws such as GDPR.

I can think of two better approaches:

  • use of a cookie your landing page, which stores the original url, and which you could reuse when your app is connecting to your website.
  • simpler and easier: provide on your landing page a short registration code (like the ones you get when making an airline reservation) that will allow to link back to the source, inform of the benefits of using the registration code before redirecting to the store, and at first use of your app, ask for this code.

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