How precise must my guest's name be spelled in the invitation so that the identity verification at the essentry kiosk works smoothly?

In general, automated identity verification of guests at the essentry kiosk is only possible if the name of the guest registered in the invitation matches the guest's official identification document (ID card, passport). Therefore, when creating an appointment, make sure that the name of the guest is spelled correctly.

Do I have to pay attention to titles, special characters, and umlauts in the invitation?

No, titles, special characters, and umlauts do not need to be included in the invitation:

• You should not include titles on the invitation. I.e. you should invite the guest without a title: Dr. John Does should be invited as John Doe. 
• Special characters and umlauts can be on the invitation, but they do not have to be. For example, if you cannot reproduce the special character with your keyboard, write the corresponding "normal" (Latin) letter. I.e. a Ç can be written as C in the invitation, an Ä as A. 
  Explanation

For the normalization of names with umlauts (ä, ü, ö etc.), special characters (e.g. ç, å, ß etc.), titles (Dr., Prof. etc.) essentry uses the standard "Machine Readable Travel Documents" (Doc 9303 Part 3) of the International Civil Aviation Organization (ICAO). According to this standard, titles, special characters and umlauts are normalized when comparing names. For example, an Ä is converted to an A, titles are deleted when normalized. 

Therefore, if you are unsure of the name on the guest's ID document, ask them for their name as found in the MRZ of the official ID document. On the picture below the name according to the MRZ is marked.

Copyright ICAO 2021