# Key4Friends > App for receiving and using digital door keys authorized by MobileKey. (iPhone/iPad app by SimonsVoss Technologies GmbH.) - Source: https://appshunter.io/ios/app/key4friends/id1141846653 (this page in markdown: same URL + `.md`) - Developer: [SimonsVoss Technologies GmbH](https://appshunter.io/developer/1141846652) - Category: Productivity - Price: Free - Age rating: 4+ - Requires: iOS 26.0 · 61 MB - Languages: American English - Released: 2016-09-19 - Data updated: 2026-09-08 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/key4friends/id1141846653/reviews.md ## What is Key4Friends? 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 – the amount of data sent is minimal. SimonsVoss Technologies GmbH hopes you have fun sharing keys safely and securely. ## Key features - Receive digital door keys - Open and close authorized doors - Secure key distribution - Easy friend sharing - Email and SMS verification ## Recent user reviews (10 of 11) All indexed reviews: https://appshunter.io/ios/app/key4friends/id1141846653/reviews.md ### 1/5 — Schliessanlage *2024-09-19, version 1.6* Die app öffnet oftmals die Schlösser nicht. Sich nur auf die App zu verlassen, ohne Transponder in der Tasche, ist ein Nervenkitzel. Leider absolut nicht ausgereift. Schade, bei solch einem teuren System ### 2/5 — Man muss Geduld haben *2023-12-13, version 1.6* Eine Tür Öffnung dauert eine gefühlte Ewigkeit. Teilweise bedarf es mehrere Versuche bis die Türe dann endlich mal öffnet. Ist nicht sehr zuverlässig. Ich würde es nicht erneut kaufen. Das muss schneller und zuverlässiger funktionieren. ### 1/5 — Mittlerweile fast unbrauchbar *2023-06-21, version 1.6* Mittlerweile im Jahr 2023 zu viele Fehlermeldungen. Funktioniert nur sporadisch . Keine update seit 3 Jahren . ### 1/5 — Horrible! *2023-06-10* I keep trying to get this to send me an SMS confirmation but so far nothing! ### 1/5 — Katastrophal unzuverlässig *2023-05-20, version 1.6* Zum zweiten Mal diesen Monat reagiert die App nicht. Man „soll sich an den Hersteller wenden“, nachts um 1 klappt das natürlich super Blöd nur wenn man da absperren muss Ich rate jedem von Simons voss ab der seine Türen regelmäßig auf und zu sperren möchten ### 1/5 — Ich bin soooo sauer! *2023-05-04, version 1.6* Wir haben unser Hotel vor einem Jahr mit diesem Schlüssel System ausgestattet. Heute früh zum x-ten mal wieder der Anruf unserer Gäste dass das System nicht funktioniert. Das geht einfach gar nicht! ### 1/5 — Ausländische Handynummer *2021-03-21, version 1.6* Funktioniert nicht mit einer ausländischen Handynummer ### 1/5 — Worst app ever. *2019-08-10* This app is the worst one I ever used. And I used many! It keeps crashing, tells me my email address is invalid when I am sure it is, I have to close the app and reopen it anytime there is a typo as I can't erase things. Wow.. Mind blown! **Developer response:** Dear User, Please get in contact with our technical support to solve the issue: support@simons-voss.com Thank you and kind regards SimonsVoss Technologies GmbH ### 1/5 — Emails give invalid codes *2019-06-28* This app has a very difficult authorization system. It tries to send an email but takes so long that by the time you get it, it is already invalid. Then it locks you out **Developer response:** Dear User, The general authentication with email and mobile number is part of the authentication process. To receive the confirmation email is sometimes delayed by the inbox email service, thus we extended the registration period to prevent such issues. Thank you for your feedback and kind regards SimonsVoss Technologies GmbH ### 3/5 — Sehr langsam *2019-05-20, version 1.5* Es dauert leider sehr lang ca. 5 min bis die E-Mail und danach nochmal ca. 3 min bis die SMS ankommt. Man brauch also gut 10 min. Zum registrieren. Den Rest kann ich nicht beurteilen weil ich auf der Suche nach einem System bin und hier erstmal die App testen wollte. ## Frequently asked questions about Key4Friends ### How does Key4Friends work? Key4Friends receives digital key authorizations from the MobileKey web app. You can then use the Key4Friends app on your smartphone to open and close the doors for which you have been granted access. ### Is Key4Friends free to install? Yes, Key4Friends is free to install. The app does not require any payment to download or begin using its core functionalities. ### What information is required for registration? During registration for Key4Friends, you will only be asked for your email address. A code will be sent via text message to verify your registration, and no password is required. ### Does Key4Friends require an internet connection? Yes, your smartphone needs to be connected to the internet to open or close a door using the Key4Friends app. The amount of data used is minimal. ### What devices is Key4Friends compatible with? Key4Friends is supported on iPhones and iPads. The app is designed to function on Apple's mobile operating systems. ### How often is Key4Friends updated? The latest version of Key4Friends is 2.5.0, which was last updated on December 15, 2025. Updates are provided to ensure continued functionality and security. ### What is the age rating for Key4Friends? Key4Friends has an age rating of 4+. This indicates that the app is considered suitable for users aged four and above. ### Does Key4Friends have ads? No, Key4Friends does not contain advertisements. The app is ad-free, allowing for an uninterrupted user experience. ## Version history (last 5 releases) ### 2.5.2 — 2026-08-31 Minor fixes and improvements. ### 2.5.0 — 2025-12-15 New implementation using modern technologies to enhance the user experience. ### 1.6 — 2020-05-04 Stability and security improvements ### 1.5 — 2019-02-14 Stability and performance improvements ### 1.4 — 2018-10-18 Stability and performance improvements ## Apps similar to Key4Friends | App | Rating | Price | Category | | --- | --- | --- | --- | | [BuildSec 4.0](https://appshunter.io/ios/app/buildsec-40/id1472711329) | — | Free | Productivity | | [CARAT easyroom](https://appshunter.io/ios/app/carat-easyroom/id1503362743) | 5.0 (1) | Free | Productivity | | [KeePassium (KeePass passwords)](https://appshunter.io/ios/app/keepassium-keepass-passwords/id1435127111) | 4.7 (1,391) | Free | Productivity | | [KeePass Touch](https://appshunter.io/ios/app/keepass-touch/id966759076) | 3.7 (342) | Free | Productivity | | [ABUS One](https://appshunter.io/ios/app/abus-one/id1670951723) | 4.7 (50) | Free | Productivity | | [heylogin – Password Manager](https://appshunter.io/ios/app/heylogin-password-manager/id1538433842) | 4.9 (59) | Free | Productivity | ## More apps by SimonsVoss Technologies GmbH - [MobileKey](https://appshunter.io/ios/app/mobilekey/id1231074427) - [SimonsVoss AX2Go](https://appshunter.io/ios/app/simonsvoss-ax2go/id6444721184) - [SimonsVoss SYNC2Go](https://appshunter.io/ios/app/simonsvoss-sync2go/id6755674137) All apps by SimonsVoss Technologies GmbH: https://appshunter.io/developer/1141846652 ## Related topics [key4friends](https://appshunter.io/ios/topics/key4friends) · [key4](https://appshunter.io/ios/topics/key4) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-08.*