How app stores check apps: what they verify and where they stop

When you install an app from your phone’s official store, you tap “Install” and a few seconds later the app is ready. Behind that tap sits a chain of checks that starts long before — when the developer opens their account and signs the app — and carries on after installation.

Knowing how app stores check apps helps you understand why downloading from the official stores makes sense, and where those checks stop: no store is infallible, and now and then a fake app gets through.

This post walks through how the stores and your phone’s operating system check apps, with their real advantages and limits, without pointing to any specific product. It is the technology side of the recommendation on checking an app is genuine: the tools do a great deal, but the last look before you install is still yours.

How to read this list

The technologies are organised into four functions, the same ones used in the post on what to do after installing a fake app:

• prevention — stopping a fake or harmful app from reaching the store or your phone;
• detection — spotting a suspicious app, before or after installation;
• response — taking the app out of circulation and limiting the damage;
• governance — the rules that hold the system together, and the ways to apply them at home or at work.

For each one you’ll find the risk it reduces, its advantages, its honest limits and how complex it is for you to use. None of them, on its own, guarantees that an app is safe: the value lies in how they add up.

1. Prevention technologies

App review, before and after publication

The check the store runs on every app and every update before making them available to download, combining automated analysis and, in some cases, human reviewers. Apps are then re-examined over time.

• Risk reduced: apps containing malware — software designed to damage your device or steal data — or apps that break the store’s rules.
• Advantages: filters out most known threats before they reach you; checks that the app declares the permissions it uses and does what its description promises.
• Limits: it doesn’t catch everything; an app can behave well during review and change later, through an update.
• Example: an app that asks for access to your text messages (SMS) with no reason linked to what it does can be held back until the request is justified or removed.
• Complexity: none for you.

Developer identity verification

To publish, a developer opens an account with the store and, more and more often, has to prove who they are: a name, an address, sometimes company documents.

• Risk reduced: apps published anonymously by people who know they won’t have to answer for them.
• Advantages: links every app to an identifiable party; on the store listing you can see the developer’s name and the other apps they have published. It’s one of the most useful clues, as the post on the signs of a fake app explains.
• Limits: it tells you who published the app, not that the app is harmless; anyone imitating a well-known service often picks a developer name almost identical to the original.
• Example: you look for your airline’s app and find two that are almost the same; only one is published by the airline. The difference is right there on the listing.
• Complexity: basic.

Code signing

Every app is signed before it is distributed. A digital signature is a mathematical seal tied to a secret key held by the developer: if anyone changes even a single byte of the app, the signature no longer matches.

• Risk reduced: tampered apps and fake updates passing themselves off as the real thing.
• Advantages: your phone checks the signature at every installation and update, and an update signed by someone else can’t replace the app you have. That’s one more reason why keeping your software up to date through the store is more reliable than accepting an update offered by a browser pop-up.
• Limits: it guarantees that the app hasn’t been altered, not that whoever signed it is honest. A clone app has a perfectly valid signature: the cloner’s.
• Complexity: none for you.

Blocking installs from unknown sources

The default setting on many phones that only allows apps to be installed from the official store. A file downloaded from anywhere else needs your explicit permission.

• Risk reduced: apps arriving from websites, messages or attachments that nobody has checked.
• Advantages: turns an install from outside the store into a deliberate choice.
• Limits: a permission granted once and then forgotten stays switched on; people spreading fake apps often walk you through unlocking it.
• Example: a message invites you to download “the courier’s new app” from a link, and your phone asks you to allow unknown sources: that’s the moment to stop and start from the official website instead.
• Complexity: basic.

2. Detection technologies

Built-in system protection

Many operating systems include protection that scans installed apps, including those that came from outside the store, and compares them with harmful apps that are already known.

• Risk reduced: harmful apps already on your phone, even ones installed before they were discovered.
• Advantages: works in the background, meaning you don’t have to start it; warns you before a risky installation. If it blocks something, it usually has good reason: better not to switch it off “just for a moment”.
• Limits: it recognises known threats better than new ones; “no problems found” is not an absolute guarantee.
• Complexity: basic; check once that it’s switched on.

The app’s store listing

The page for each app: the developer, the date of the latest update, a rough number of downloads, the permissions requested, and a section where the developer declares what data the app collects.

• Risk reduced: installing an app without knowing who made it or what it asks for.
• Advantages: gathers almost every useful clue in one place and lets you compare two similar apps. The resource on checking app details explains how to read it methodically.
• Limits: the privacy information is declared by the developer and not always checked in depth; download numbers can be inflated.
• Complexity: basic.

User reviews and reports

Ratings and comments left on the store, which inform other readers and also feed into the store’s own checks.

• Risk reduced: problem apps that slipped through review.
• Advantages: recent, detailed reviews often describe problems that automated checks can’t see.
• Limits: reviews can be bought or written in bulk, and a high rating says little on its own, as the resource on fake app reviews explains.
• Complexity: basic.

3. Response technologies

Removal from the store

When an app is identified as fake or harmful, the store takes it out of the catalogue and, in serious cases, closes the developer’s account.

• Risk reduced: new installs of an app that has already been identified.
• Advantages: stops it spreading for everyone, often together with the other apps from the same account.
• Limits: people who have already installed it usually keep it; those who publish fake apps can try again with a new account.
• Complexity: none for you.

Disabling apps that are already installed

On some systems, built-in protection can disable or remove a harmful app that is already on your phone, usually letting you know.

• Risk reduced: apps that have been discovered but keep running on your phone.
• Advantages: reaches people who haven’t noticed anything, across many devices at once.
• Limits: it isn’t available everywhere and doesn’t undo what the app has already done; for the next steps, see the post on what to do after installing a fake app.
• Complexity: basic.

Revoking developer certificates

A certificate is the digital document that states who a signing key belongs to. If a developer seriously breaks the rules, their certificate can be revoked and their apps stop being treated as trustworthy.

• Risk reduced: apps signed by parties who turned out to be acting in bad faith.
• Advantages: hits every app tied to that signature; on some systems it also stops those apps from opening.
• Limits: it comes after the discovery; how it works varies from one system to another.
• Complexity: none for you.

Reporting by users

The option, found on every app’s listing, to report it to the store as fake or misleading.

• Risk reduced: fake apps that stay online because nobody reports them.
• Advantages: takes less than a minute and protects whoever would look for that app after you.
• Limits: it has no immediate effect and doesn’t replace the steps you need to take on your own phone.
• Complexity: basic.

4. Governance technologies

The rules that give everything else its consistency, and the tools to apply them when the phone isn’t only yours.

Publishing rules and sensitive permissions

Every store sets out what an app may do and how it must declare it. A permission is the authorisation you give an app to use a feature or a piece of data on your phone; the most sensitive ones — text messages, location in the background, accessibility features that can read the screen — need a justification.

• Risk reduced: apps that collect more data, or take more control, than they need.
• Advantages: raises the bar for abuse and makes an out-of-place request easier to recognise. To manage permissions after installation, see the recommendation on checking what your apps can do.
• Limits: an app can ask for the “right” permission and still misuse it.
• Complexity: basic.

Official links between website and app

The simplest way to reach the right app is to start from the service’s official website and follow its link to the store. There are also verified links: the website declares, in a small file, which app belongs to it.

• Risk reduced: clone apps found by searching for the service’s name.
• Advantages: moves the check to a place the service really controls, its own website; with verified links, an unrelated app can’t open that website’s links in place of the official one.
• Limits: you need the real website: an almost identical address, for example with “download” or “app” added to the name, can lead to a copy. Not every service uses verified links.
• Example: instead of searching for “bank” in the store, you type the address you know and follow the link to the app from there.
• Complexity: basic.

Alternative stores and free software repositories

Other distribution platforms exist too. Some are free software repositories, meaning collections of apps whose source code — the instructions the app is written in — is public; some of these build the apps from that code themselves and use labels to flag unwanted features such as tracking.

• Risk reduced: relying on checks that nobody outside can observe.
• Advantages: anyone can examine the code; the labels make visible choices that stay hidden elsewhere.
• Limits: checks vary widely from one platform to another, and a website that calls itself a “store” isn’t a serious platform just for that.
• Complexity: intermediate.

Approving installs at home and at work

Parental controls and work device management let you require approval before every installation, or limit installs to an agreed list.

• Risk reduced: fake apps installed in a hurry or by someone with less experience.
• Advantages: adds a second pair of eyes when it matters; at home, it becomes a chance to learn together.
• Limits: if it’s only a ban, it pushes people towards shortcuts.
• Complexity: intermediate.

Comparison table

How to choose

If you’re an individual. Install from the official store, keep unknown-source blocking and built-in protection switched on, and for apps that handle money, identity or documents always start from the service’s website. Before you tap “Install”, spend ten seconds on the listing: developer, date, permissions.

If you have a family. Add install approval on your children’s phones and look at the listings together. With older parents, remind them that no serious service asks you to install an app from a link sent by message.

If you use your phone for work, or run a small organisation. Agree on a list of approved apps, with the official link for each one; with several devices, central device management can limit installs to that list.

A rule of thumb. Store checks reduce the risk considerably, but they don’t eliminate it: a fake app occasionally gets through, and an honest app can change with an update. The combination that gives the best result for the effort involved is official store + link from the service’s website + a glance at the developer: technology does most of the work, and your own look covers the rest.

How this connects to the Cyber Welfare Framework

Reference level: FL3 — Autonomous. This is the level at which you use your own device’s tools without step-by-step guidance, knowing when to trust them and when to take a closer look.

Conclusion

Official app stores don’t promise that every app is harmless. They offer something more concrete: knowing who published an app, guaranteeing it hasn’t been altered, and being able to take it out of circulation when something goes wrong. Understanding how they work helps you use them well, and recognise the small space where your own attention is still needed.

To see how solid your digital habits are overall, you can start with the digital resilience self-assessment.

What to do next. Check in your settings that built-in protection is switched on and that no app is still allowed to install other apps from unknown sources. Then open the store listing of the most important app you use, your banking app for example, and check that the developer matches the one named on the official website.

Related content

• Checking an app is genuine — the recommendation this belongs to
• What to do after installing a fake app — how to put things right, in order, when the checks weren’t enough
• Cloned and counterfeit apps — the techniques these checks are designed against
• Signs of a fake app — what to look for on the listing and on your phone

Related resources

Short pieces from the Resources section, for anyone who wants to focus on a single aspect:

• Check App Details: The Filter Before You Install
• Download Security: Deciding Before You Install
• Fake App Reviews: Why the Rating Tells You Little

Start with the first step: the Cyber Welfare Programme guides you free of charge, one recommendation at a time.