The HADDOCK web server is a user-friendly platform for data-driven biomolecular docking, facilitating the modeling of complex structures. It supports a wide range of experimental data, including mutagenesis, mass spectrometry, NMR experiments, and bioinformatic interface predictions. The main interface requires only the structures of individual components and a list of interacting residues, while additional interfaces allow advanced users to customize the docking process. HADDOCK incorporates experimental information through Ambiguous Interaction Restraints (AIRs), which are generated based on active and passive residues. The server uses a dedicated cluster and e-NMR GRID infrastructure to handle computational demands, making typical docking runs quick and efficient. The HADDOCK server has been widely used, with over 534 registered users and more than 3450 docking runs processed as of December 2009, demonstrating its effectiveness in predicting complex structures.The HADDOCK web server is a user-friendly platform for data-driven biomolecular docking, facilitating the modeling of complex structures. It supports a wide range of experimental data, including mutagenesis, mass spectrometry, NMR experiments, and bioinformatic interface predictions. The main interface requires only the structures of individual components and a list of interacting residues, while additional interfaces allow advanced users to customize the docking process. HADDOCK incorporates experimental information through Ambiguous Interaction Restraints (AIRs), which are generated based on active and passive residues. The server uses a dedicated cluster and e-NMR GRID infrastructure to handle computational demands, making typical docking runs quick and efficient. The HADDOCK server has been widely used, with over 534 registered users and more than 3450 docking runs processed as of December 2009, demonstrating its effectiveness in predicting complex structures.