A microfluidic droplet-handling architecture for the synchronization of asynchronous, mis-matched, pre-formed droplet streams is demonstrated. This architecture is shown to be robust to variations in droplet input frequencies, whilst still producing highly reliable synchronisation. The operational phase space with regards to droplet size disparity is explored and the long-term operational stability of the system confirmed. Specifically, the microfluidic platform to synchronies droplet streams at a rate of 33 Hz over extended periods of time and with an error rate less than 0.2%.