Pump–probe laser system at the FXE and SPB/SFX instruments of the European X-ray Free-Electron Laser Facility

User operation at the European X-ray Free-Electron Laser Facility started at the SASE1 undulator beamline in fall 2017. The majority of the experiments utilize optical lasers (mostly ultrafast) for pump–probe-type measurements in combination with X-ray pulses. This manuscript describes the purpose-developed pump–probe laser system as installed at SASE1, implemented features and plans for further upgrades.