E-commerce development in Indonesia continues to be the center of Southeast Asia's attention, with its potential in both B2B and B2C models. With predicted growth up to US $ 300 billion in 2020, many e-commerce aims to create new value in a new product/service. It is widespread for startup e-commerce launch partnerships or collaboration programs to increase e-commerce opportunities to grow even more. Some e-commerce has launched their collaboration program with significant results in quality growth. The decision making in e-commerce collaboration tends to be intuitive, centralized, and not using strategic management tools. This research aims to identify critical success factors (CSF) as primary considerations in making collaborative decisions between e-commerce companies by developing a questionnaire with employees and decision-makers using TOE framework in e-commerce collaborations. The object of this research is B2B and B2C company that conducted collaboration partnership in the last 1 year. While research limited to ranking of CSFs, further studies by using another method need to be conducted for more comprehensive analysis.