T1 mapping provides crucial information about the myocardial tissue in different cardiomyopathies. The clinically used method is the MOLLI sequence, but differences within the magnetic resonance (MR) sequence, that are not clear to the final user, can lead to T1 variability. Open-MOLLI is an open-source sequence for myocardial T1 mapping sequence fully available, that allows to perform the same MR sequence in different systems. This work shows that the Open-MOLLI sequence can be used for T1 mapping in vivo with similar results to the MOLLI method. This increases the accessibility of T1 mapping in research centres, facilitating standardisation and further improvements. See more.