MM-OpenFGL: A Comprehensive Benchmark for Multimodal Federated Graph Learning
Xunkai Li, Yuming Ai, Yinlin Zhu, Haodong Lu, Yi Zhang, Guohao Fu, Bowen Fan, Qiangqiang Dai, Rong-Hua Li, Guoren Wang
TL;DR
MM-OpenFGL formalizes multimodal federated graph learning (MMFGL) and introduces the first comprehensive benchmark for it, integrating 19 multimodal datasets, 8 simulation strategies, 57 methods, and 9 downstream tasks. The framework supports two training pipelines—End-to-End FGL and a Two-Stage pretraining–finetuning approach—within a modular OpenFGL-like API. Through extensive experiments, the work provides 10 key insights, highlighting the limits of naive adaptations, the importance of cross-modal alignment and structural resilience, and the superior generalization of graph foundation models across diverse tasks. The benchmark and findings offer practical guidance for designing privacy-preserving, scalable MMFGL systems and come with an open-source library to foster future research and fair comparisons.
Abstract
Multimodal-attributed graphs (MMAGs) provide a unified framework for modeling complex relational data by integrating heterogeneous modalities with graph structures. While centralized learning has shown promising performance, MMAGs in real-world applications are often distributed across isolated platforms and cannot be shared due to privacy concerns or commercial constraints. Federated graph learning (FGL) offers a natural solution for collaborative training under such settings; however, existing studies largely focus on single-modality graphs and do not adequately address the challenges unique to multimodal federated graph learning (MMFGL). To bridge this gap, we present MM-OpenFGL, the first comprehensive benchmark that systematically formalizes the MMFGL paradigm and enables rigorous evaluation. MM-OpenFGL comprises 19 multimodal datasets spanning 7 application domains, 8 simulation strategies capturing modality and topology variations, 6 downstream tasks, and 57 state-of-the-art methods implemented through a modular API. Extensive experiments investigate MMFGL from the perspectives of necessity, effectiveness, robustness, and efficiency, offering valuable insights for future research on MMFGL.
