A modular manifold system is provided for interconnecting fluid components of a fluid system in a reduced area. The system is comprised of a one or more bridge fittings having an internal fluid passageway which has an inlet end in fluid communication with an outlet port of a first fluid component, and an outlet end in fluid communication with an inlet port of a second fluid component. The bridge fittings may additionally comprise two or more ports, which one of said ports may be in fluid communication with a manifold on another substrate level. The bridge fittings may be mounted within a channel of a backing plate for structural support or in channel blocks of varying sizes. The bridge fittings may be stacked to form multiple layers where bridge fittings of one layer may be in fluid communication with bridge fittings of another layer.