The paper reports the discovery and detailed analysis of a massive pulsar in a compact relativistic binary system, PSR J0348+0432. The pulsar has a mass of 2.01 ± 0.04 solar masses (M⊙) and orbits a white dwarf with a mass of 0.172 ± 0.003 M⊙ in a period of 2.46 hours. This system provides a unique laboratory to test strong-field gravity, as the high pulsar mass and compact orbit allow for precise measurements of the orbital decay. The observed decay agrees with general relativity (GR), supporting its validity even under extreme conditions. The constraints on deviations from GR are consistent with the use of GR-based templates for ground-based gravitational wave detectors. Additionally, the system strengthens recent constraints on the properties of dense matter and offers insights into binary stellar evolution and pulsar recycling. The paper discusses the implications of these findings for testing alternative theories of gravity, particularly scalar-tensor theories, and their potential impact on future gravitational wave astronomy.The paper reports the discovery and detailed analysis of a massive pulsar in a compact relativistic binary system, PSR J0348+0432. The pulsar has a mass of 2.01 ± 0.04 solar masses (M⊙) and orbits a white dwarf with a mass of 0.172 ± 0.003 M⊙ in a period of 2.46 hours. This system provides a unique laboratory to test strong-field gravity, as the high pulsar mass and compact orbit allow for precise measurements of the orbital decay. The observed decay agrees with general relativity (GR), supporting its validity even under extreme conditions. The constraints on deviations from GR are consistent with the use of GR-based templates for ground-based gravitational wave detectors. Additionally, the system strengthens recent constraints on the properties of dense matter and offers insights into binary stellar evolution and pulsar recycling. The paper discusses the implications of these findings for testing alternative theories of gravity, particularly scalar-tensor theories, and their potential impact on future gravitational wave astronomy.