Number of subjects
Max. 3 subjects (incl. tracking) for physical delivery. (Native ads: a maximum of 5 text/image combinations are possible per language region and campaign).
If more than 3 subjects are delivered, they must be delivered via a 3rd party tag and the advertising media must be exchanged on the customer side.
The exchange of physical subjects during an ongoing campaign is only permitted in exceptional cases.

Animations
The length of the animation within an advertising banner is not limited. However, the recommended maximum length is 30 seconds.

Flash
Flash files are not permitted.

SSL
All third party tags, tag-in tags and references in an HTML5 file must be delivered via SSL (https://).

HTML5

The maximum weight (according to specs) refers to all files together in an unzipped state.
The target URL and trackings must be stored in the HTML5 banner.
The target URL must be opened in a new tab (target='_blank').
Ad media tests must be possible locally in the browser.
UTF-8 encoding
Special characters that are not displayed correctly in the browser with UTF-8 must be encoded manually (e.g. [&]auml; instead of ä).
References in the advertising material to external resources (JS libraries, videos, fonts) must all be delivered via SSL (https://).

Skip button
To activate the "skip button" for instream videos that use a VAST redirect, the "Skip Off-Set" parameter must be added by the customer in the VAST redirect.

General guidelines Ad Manager

General guidelines

A timely campaign start is only guaranteed if the delivery deadlines are met.
The advertiser is responsible for the smooth functioning of the advertising media.
A campaign may be withheld if it does not meet the specifications.
Max. 1 count pixel and 1 click command (PreRoll [&] Bumper, Desktop [&] Mobile)
Advertising from the erotic sector requires prior clarification and can be rejected by the publisher.
Advertising media are tested on the most common devices, screen resolutions and browsers. Certain individual settings or configurations may lead to deviations in the display of the advertising material.

Instructions ClickTags HTML advertising media Google

Instructions ClickTags HTML advertising media Xandr

Specification