qgraf is a computer program that can generate Feynman diagrams and represent them by symbolic expressions (no graphical representation is generated, though). It was created with the obvious aim of contributing to extend the range of feasible perturbative-QFT calculations.

• Latest version: qgraf-3.4 (January 2019).
  Please report any error you may happen to find.
  

• Programming language: Fortran (mostly FORTRAN 77; valid Fortran 95 syntax, though).
  Binaries/executables are not distributed, the program has to be compiled and linked;
  compiling with GNU's gfortran should be straightforward, eg there should be no need
  to specify a Fortran standard.

• The features added since the release of qgraf-3.1.5 include:
  option “onshellx”, an extended form of “onshell” (3.2);
  improved treatment of duplicate vertices (3.3);
  a way of restricting the configuration of external lines (3.3);
  the ability to require/disallow bridge-type propagators with certain momenta (3.3);
  an option to select diagrams with non-factorizable cycle spaces (3.4);
  an option to select 1-vertex irreducible diagrams (3.4).

• Current plans: qgraf-3.4 should be the next ‘stable’ version (ie available for a long
  period, minimal fixes if need be), hopefully replacing qgraf-3.1 in that regard.
  The next release is unlikely to be available before 2020; plans include generation
  of counterterm diagrams.

The diagram generation is based on the method described in the following article:

• Automatic Feynman graph generation
  P. Nogueira
  J. Comput. Phys. 105 (1993) 279-289
  https://doi.org/10.1006/jcph.1993.1074