Einstein’s theory of general relativity has withstood 100 years of experimental scrutiny. However, these tests do not constrain how well the very strong gravitational fields produced by merging neutron stars obey this theory. New, more sophisticated techniques can now search for deviations from general relativity with unprecedented sensitivity. Scientists at the Max Planck Institutes for Gravitational Physics and for Radio Astronomy studied two foremost tools for testing the strong-field regime of gravity – pulsar timing and gravitational-wave observations – and demonstrated how combining these methods can put alternative theories of general relativity to the test.