In the month of August 2018, Kerala, the southernmost state of India, received 250 % of normal rainfall, resulting in all of its 44 dams to be opened. Over 483 people died due to the flooding caused by the opening of dams and a million people were evacuated. I started a website ([keralarescue.in][1]), written in Django. The main purpose of the site was effective collaboration and communication between authorities, volunteers and public. The site was open source from Day 0. About 1500 developers and volunteers onboard our slack group in a couple of days. Within a week, the community united to forge a critical piece of software that saved thousands of lives. The site initiated as a portal for refugees to request essential resources like food and water and for volunteers to see their needs, all sorted by geographical location. Additionally, we provided direct information for the government and became the official website later on. The Minimum Viable Product was delivered in fourteen hours. In the initial days, it was only used by the volunteers and Point of Contacts assigned by the government. Later, when the situation became critical, we started getting rescue requests from stranded refugees. The Github repo of the website went viral, and we started to receive feature requests rapidly. We received more than five hundred pull requests in the span of three weeks. The story I want to present is about the community and technical aspects of keralarescue.in, how people from different backgrounds came together to build a critical piece of software that saved many lives. [1]: https://keralarescue.in