Key4Friends vs BuildSec 4.0
Price, ratings, monetisation and update history for both apps, side by side ā with what reviewers say about each.
Key4Friends
Easily and securely share access to doors with friends and family. Receive authorizations from the MobileKey app to open and close designated doors directly from your smartphone. Requires an internet connection for operation.
- Receive digital door keys
- Open and close authorized doors
- Secure key distribution
- Easy friend sharing
- Email and SMS verification
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Safe distribution of keys among friends has never been easier: the Key4Friends app receives keys which the owner wishes to share with you from the MobileKey app. The function is quickly explained: the owner of the door sends you an authorisation for one or more doors over the MobileKey web app. You can then open and close the doors concerned using the Key4Friends app. Key4Friends is quick, easy, safe and free to install. You will only be asked for your email during registration. We will then send you a code by text message to check registration. No password is required thanks to the distinct connection between the SIM card and the email address. Important: your smartphone needs to be connected to the Internet to open or close a door with the Key4Friends app. This means that there may be charges, depending on the contract with the operator. Don't worry, though ā the amount of data sent is minimal. SimonsVoss Technologies GmbH hopes you have fun sharing keys safely and securely.
BuildSec 4.0
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Using the alarm system app BuildSec 4.0 you are in control of your modern TELENOT hazard alarm system at any time and any place. The alarm system app BuildSec 4.0 is a user software application for smartphones and tablets. The operation of the alarm system app is identical to operation of the keypad BT 800. OPERATION ⢠Setting/unsetting of all partitions ⢠Indication of open dedicated signals (door, window, etc.) ⢠Alarm messages and location in plain text ⢠Disabling of input groups ⢠Operation of switching functions ⢠Displaying of the event memory ⢠Disabling/enabling of the keypad codes CONNECTION MODES ⢠Connection via digital platform hiXserver (currently for intruder alarm control panels complex) ⢠Direct connection between app and alarm system ADVANCED FUNCTIONS ⢠Storage of access data of properties in the application of smartphones/tablets ⢠Optional encryption of property access data is possible ⢠Exporting access data via QR codes ⢠Importing access data via QR code scan ⢠Favorites list ⢠Encrypted data transfer from smartphones/tablets to alarm system ⢠Password-protected login ⢠User authentication via Face ID or Touch ID COMPATIBLE HAZARD ALARM SYSTEMS ⢠Intruder alarm control panel hiplex 8400H (from firmware version 01.01, recommended: firmware version 3 or higher) ⢠Intruder alarm control panels complex 200H / 400H, wireless alarm system compact easy (from firmware version 15.43) in connection with transmission devices 1516 / 2516 / 3516 (from firmware version 6.20)
Screenshots
Verdict
The clearest difference is update cadence: BuildSec 4.0 at every 2 months against Key4Friends's every 9 months. BuildSec 4.0 also leads on iOS requirement (16.4 vs 26.0). On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price Ā· Rating Ā· Positive reviews Ā· Number of ratings Ā· Update frequency Ā· Ads Ā· In-app purchases Ā· Monetization Ā· Best chart rank Ā· Devices Ā· Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Key4Friends ships an update every 9 months, BuildSec 4.0 every 2 months. The most recent releases landed on November 2, 2026 and November 3, 2026 respectively.
| Parameter | Key4Friends | BuildSec 4.0 |
|---|---|---|
| Price | Free | Free |
| Positive reviews | 9.1% of reviews | ā |
| Update frequency | Every 9 months | Every 2 months ā better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | ā |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 26.0 | 16.4 ā better |
| Further details ā not scored | ||
| Size | 61 MB | 205 MB |
| Age rating | 4+ | 4+ |
| Developer | SimonsVoss Technologies GmbH | Telenot Electronic GmbH |
In-app purchases
Key4Friends
No in-app purchases
BuildSec 4.0
No in-app purchases
Questions
Is Key4Friends free?
Is BuildSec 4.0 free?
Do Key4Friends or BuildSec 4.0 have ads?
Which is updated more often, Key4Friends or BuildSec 4.0?
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