In QGIS Server 3.4, the WMTS API was added in which the tile matrices are calculated except for EPSG:3857 and EPSG:4326.
This change adds the capability to select the tile matrices to use with the project and to configure the top-left corner and the last level of the tile matrix. In the case of EPSG:3857 and EPSG:4326, the user can only choose the last level of the tile matrices.
This feature was funded by Ifremer
This feature was developed by 3liz