Ask for Blynk's features

Hi. I want to create a smart door lock with RFID, keypad, fingerprint and wifi
Can I use Blynk to

  1. Notification when door opening fails to exceed the specified number of times
  2. Display unlock history (by keyboard, fingerprint…)

Yes you can use BlynkIoT for your use case.

You’ll obviously need to be able to identify these situations and events in your device to be able to send them to Blynk, and have a WiFi connection to send them to the Blynk server.

Also, Blynk has a limitation of 100 events per event type, and 100 notifications, in any 24 hour period.
If you envisage that these limits may be exceeded in some situations then you may have an issue.