Deep Linking: Fundamental Concepts Explained | AppsFlyer
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Chapter 1

Deep Linking Basics: Deep Links are Just Links

What is a deep link?

Well, most people may not know the term, but they do know what links are. You can’t understand deep links if you don’t understand links.

We use links to drive users to product pages, to execute paid campaigns on Facebook, to route users to the app store from web and email, and even to communicate important offers and deals in the app.

deep links examples

Links are used by apps, big and small to drive users to the proper destination on the web.

So, then, what is a link? A link is sometimes referred to as a URL or URI (Universal Resource Locator / Indicator). A link is merely an address, name or reference to a file on “The internet”! You can think of it as a specific address on a specific street in a specific ZIP. When you go searching for ‘https://www.walmart.com’, you’re working in the same mental model as if you go searching for an actual address in the world.

Where this analogy diverges is that a link, or URL, refers not to a house with an address, but to a file with a digital address – this address is the URL. Most URLs refer to a file on some computer or machine on a network that exists in the world. Just as we know addresses reference a house, office, or residence somewhere in the world, digital addresses – links – do the same thing with files and resources on the internet.

Links, or URLs, can refer to many types of resources, just as physical addresses can refer to many types of structures, like apartments, malls, offices, government buildings and more. URLs can be files (like an HTML page), databases, APIs, and much more.

A Link is a URL, and a URL is a URI
This is hopefully where the dots will start to connect. In mobile, the term “URI” is flung around often, but most folks don’t know what this is or how it relates to everyday links.

In programming, a URI (Uniform Resource Identifier) is just a string of characters to identify the name of a resource on a network. A URI is just another address in the world.

But, the most common URI out there is the URL, a Uniform Resource Locator, which we have now discussed at length. URIs are not just limited to this so when you hear “URI scheme” or “URI” you should know that people are actually just talking about garden variety links, the same type you likely use in email campaigns, affiliate promotions and on social media to promote products or your app.

Let’s put our knowledge into practice and look at a link:

Example Link
‘https://www.walmart.com’

This is a URL or “link”. It has two main components, separated by a colon.

Protocol Identifier (Scheme)
‘https’ – this is the protocol identifier or the scheme.

Resource Name
‘www.walmart.com’ – this entire string is called the “Resource Name.” It includes the subdomain, domain and top level domain (in that order) combined into a single string. While not explicitly seen here, everything after the final slash “/” is called the “path” or “pathname”. If the URL is an address, then the pathname is the actual room in the house or building that the URL refers to!

If we think back to our physical address analogy, the scheme identifier most accurately embodies the mail carrier you use to send mail to the address. There’s UPS, Fedex, USPS and other options. Similarly, in the digital world, there are many types of schemes over which to send data, like accessing a website, downloading a file or even sending digital mail. Other schemes include File Transfer Protocol (ftp), Gopher (gopher), File (file), and News (news).

HTTP stands for Hyper Text Transfer Protocol (HTTP), which is typically used to serve hypertext documents. The “S” in HTTPS is just the secure version of HTTP – it actually just stands for “Secure.” The HTTP and HTTPS protocols are typically used to send data between your browser and the website address you’re accessing.

Links as Addresses

Here’s a comparison of a real life address to a digital address, and how the components of each are related. As you can see, just like a physical address, a link has similar identifying features. Understanding how links are structured is the basis of understanding what deep links are and how they behave in a variety of situations.

What it’s CalledReal Life Address Digital AddressWhat it’s Called
Complete Mailing AddressFacebook
1 Hacker Way, Suite 1
Menlo Park, CA 94025
 https://www.facebook.com/zuckComplete Digital Address
(Link or URL)
Recipient LineFacebook facebookSubdomain
Delivery AddressMenlo Park, CA 94025 wwwDomain
CountryUnited States .comTop Level Domain
Carrier/Mail DeliveryUPS, Fedex, USPS HTTP, FTP, fb://Protocol Identifier or Scheme
Building & Office, Apartment, Suite etc.1 Hacker Way Suite 1 zuckPath

 

Key Takeaways

  1. A link is just a digital address. An address is to a map as a link is to the internet.
  2. A link is a URL. A URL is a type of URI. These things have fancy names, but at their core serve the same purpose and mean similar things.
  3. A URL is made up of a “Scheme” and a “Resource Name.” The “Resource Name” has four important components:
    1. Subdomain
    2. Domain
    3. Top Level Domain
    4. Path
  4. Deep links are very specific URLs, just like specific websites or physical addresses.

 

URI Schemes – Mobile App PO Boxes

Deep linking starts and ends with URLs, or URIs. Just as we discussed before, a link and a URL are one in the same.  At a very high level a deep link is a link, or a special URL that routes to a specific spot, whether that’s on a website or in an app. These particular spots are deep links. These might not be publicly visible to the world, but they exist as a real place to reference.

Key Point:

The term “deep link” has come to mean the routes to specific spots on websites and to a native application via a link. A version of the term, called a “mobile deep link,” is a link that contains all the information needed to take a user directly into an app or a particular location within an app instead of just launching the app’s home page.

URL vs. URI scheme

Deep links on the web are no different than deep links for apps – in both cases, links conceptually function the same. The only difference is the way they look and behave. Most often people interchange the term URI or “URI Scheme” with a deep link. This is not only technically incorrect, but creates endless confusion.

The proper way to think about deep links is as follows:

– There are many types of deep links – including deep links that go to websites and to the app
– A deep link is just a link, which is a URL
– URLs can be deep links

Here is where things all come together: Remember the thing we talked about before, “schemes”?

An app can have its own special way of opening via a customized, registered scheme. This is called the app’s “URI Scheme”. You can think of a “URI Scheme” like PO Boxes. You can send mail to PO Boxes, but some differences & restrictions apply. They don’t behave the same as regular mailing addresses. Each app has its own URI scheme that is registered to the app with the app stores and which is specially designed just to open that app.

deep link?Link ExamplesDescription
Nohttps://newyorktimes.comThis is a link that goes to a “top level domain” page. This is not a deep link because it doesn’t go anywhere deeper within the domain.
Yeshttps://www.hbe.io/aboutThis is a deep link because it goes to a place deeper within the website than just the main splash page.
Yes (Kind of)newyorktimes://This is the iOS URI Scheme to launch Times’ mobile app. People often interchange this with the term “deep link” which is incorrect.
The correct thinking is that this URI Scheme can deep link a user into the app in certain contexts.
Yesnewyorktimes://ip/Trump-Korea-Tensions/172218418 This is a deep link. It is the iOS URI Scheme to launch the Times’ mobile app followed by the “route” to deep link a user to this particular item.

Key Takeaways

  • A URI Scheme is a way to directly open the app if it is installed on the device – this is the same as being able to send mail to a very specific Box if you have a PO Box number. The PO Box system is regulated by USPS, just like URI Schemes are regulated by the app engineers and the App Stores.
  • The term “deep links” is often incorrectly interchanged with an app’s URI Scheme. A URI Scheme with a specific path (`newyorktimes://ip/Trump-Korea-Tensions/172218418`) is a deep link.
  • All of these are deep links:
    • https://www.facebook.com/zuck
    • fb://zuck
    • newyorktimes://ip/Trump-Korea-Tensions/172218418
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