List of popular open source Fortran projects

In order to more easily judge how Fortran developers actually use Fortran in real production codes, we maintain a list of popular open source Fortran projects here (GitHub lists Fortran as the main language), sorted by the number of stars at GitHub (in parentheses), for now we set the limit to at least 29 stars:

Project	Stars	Contributors
OpenBLAS	3071	128
fortran-machine	494	2
LAPACK	486	43
ElmerFEM	349	26
WRF	338	45
fds	285	49
functional-fortran	266	1
Quantum ESPRESSO	219	46
fluidity	189	36
fortranlib	187	1
json-fortran	178	4
Nek5000	168	30
cp2k	167	41
fortran2018-examples	164	1
NASTRAN-95	156	1
specfem3d	152	23
NWChem	147	45
gtk-fortran	147	4
CFL3D	130	2
fortran-utils	123	5
SHTOOLS	118	8
OpenCoarrays	117	14
arpack-ng	115	31
DFTB+	113	13
NASTRAN-93	113	1
MPAS	111	37
neural-fortran	111	5
NetCDF-Fortran	105	17
CTSM	102	22
Castro	100	30
ABINIT	97	23
FLAP	85	5
bspline-fortran	83	1
FOODIE	80	3
forpy	77	4
OFF	76	2
WAVEWATCH III	76	12
MOM6	75	41
VTKFortran	72	3
datetime-fortran	70	6
node-fortran	69	2
Fortran-Astrodynamics-Toolkit	68	1
pyplot-fortran	66	5
Starlink	65	31
WPS	65	10
ogpf	62	1
pFUnit	61	13
tcp-client-server	58	1
ftl	57	2
fgsl	56	4
OpenCMISS	56	25
StringiFor	55	5
wrf_hydro_nwm_public	53	22
SciFortran	50	2
bandup	49	3
LaGriT	48	8
stdlib	47	7
clfortran	46	1
fox	45	8
HANDE-QMC	44	12
FEconv	44	4
lesgo	44	7
FortranPatterns	43
FV3-GFS	43	1
coretran	40	2
tsunami	40	1
fdict	39	1
CFD	39	1
coretran	39	2
ICAR	39	7
MODFLOW6	39	6
PIC Skeleton Codes	38	4
IAMR	36	14
ADflow	34	17
PoisFFT	33	2
sigma	33	1
aenet	32	2
DBCSR	32	14
GALAHAD	32	1
node.fortran	32	1
h5fortran	31	2
kdtree2	31	1
numerical-methods-fortran	31	1
TRACMASS	31	3
CompDam	30	3
Flexi	56	12
GFR	30	2
OpenSWPC	30	1
ROMS	30	4
slsqp	30	2
Truchas	30	8
fortran-csv-module	30	3
FMS	29	27
SNAP	29	6
freeCappuccino	29	1

Non Github projects

Project	Stars-equivalent	Contributors
MESA	~1000 users on mailing list	16

Note: Probably most Fortran codes are actually not open source, but rather maintained at big labs and corporations. But it is still useful to at least be able to see the open source landscape.

Note: The number of stars roughly correspond to how many people find the project interesting. The longer the project is at GitHub, the more stars it generally gets, so it is not completely fair to compare a 10 year old project with a 0.5 year old project in terms of stars. Also some projects game the number of stars (ask people to star the project, etc.).

Note: The number of contributors correspond to how healthy the project is in terms of development and it is a proxy how many users the project actually has (typically a small percentage of users contribute fixes back to the project and increase the contributor number). The contributor number that GitHub displays might not be the complete number, as some projects had lots of contributors before moving to git and GitHub.

Discussion: you can discuss this list at the associated issue https://github.com/fortran-lang/stdlib/issues/28.