We propose an online algorithm for planning under uncertainty in multi-agent settings modeled as DEC-POMDPs. The algorithm helps overcome the high computational complexity of solving such problems off-line. The key challenge is to produce coordinated behavior using little or no communication. When communication is allowed but constrained, the challenge is to produce high value with minimal communication. The algorithm addresses these challenges by communicating only when history inconsistency is detected, allowing communication to be postponed if necessary. Moreover, it bounds the memory usage at each step and can be applied to problems with arbitrary horizons. The experimental results confirm that the algorithm can solve problems that are too large for the best existing off-line planning algorithms and it outperforms the best online method, producing higher value with much less communication in most cases.