The Flux data kit is an effort to expand upon the existing work by Ukkola et a. (2022) to synthesize various sources of ecosystem flux data (i.e. the PLUMBER2 data set, gathered from all major networks). We further expand upon the original data set by integrating data which was either expanded upon (temporally) or where sites were added (e.g. the integration of ICOS data). The effort uses the FluxnetLSM package by the above mentioned authors, as well as their general workflow. In contrast to the PLUMBER2 data set we do not apply stringent quality control, and all quality control on the availability of variables and/or their duration should be done by the user. Furthermore, we include both leaf area index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) in the netcdf output, where PLUMBER2 only provided LAI. On all other parts the formatting and naming conventions as well as quality control specifications remain the same as in PLUMBER2. We therefore refer to Ukkola et al. (2022) for details. Data included The data included consists of the following files, containing different versions of the same data and site meta information. FLUXDATAKIT_LSM.tar.gz file contains compressed NetCDF files compatible with the ALMA scheme for land surface modelling. FLUXDATAKIT_FLUXNET.tar.gz file contains data in a CSV format according to the FLUXNET specifications. rsofun_driver_data_v3.3.rds file is a compressed serialized R file containing data formatted for use with the {rsofun} R package. fdk_site_info.csv contains site meta information in tabular form fdk_site_fullyearsequence.csv contains information about complete sequences of good-quality data by site (see also here). Data generation Data is generated using the FluxDataKit project. Although this project is not meant for continuous releases, and no support is provided in using this code with data provided AS IS, it might still be useful to some: https://github.com/geco-bern/FluxDataKit The data can be further complimented using the FluxnetEO dataset, which is accessible through the package with the same name as found here: https://github.com/geco-bern/FluxnetEO Acknowledgements The flux data kit is part of the LEMONTREE project and funded by Schmidt Futures and under the umbrella of the Virtual Earth System Research Institute (VESRI). References: Ukkola, Anna M., Gab Abramowitz, and Martin G. De Kauwe. "A flux tower dataset tailored for land model evaluation." Earth System Science Data 14.2 (2022): 449-461.