Our two companies became partners in the project of front-end Web and Application development. We developed by sharing GitHub repository, deciding the responsibilities of each side through communication between our engineers and Relipa's.
If GitHub and Slack are often used to inform requirements in Japanese, all those requirements would be handled at a amazingly high speed. Moreover, if the requirements given are ambiguous, the company will check carefully by appropriate questions to ensure that there will be no conflict or disagreement exist.
Although 1 year of cooperation was somehow short, I was really impressed by the high responding speed, as well as the company had been trying their best to improve speed and quality day after day compared to the first day we joined partnership.