Government Subsidy Registry is a Serbian government service that allows its every citizen to apply for the direct donation of 100 EUR as an economic help measure due to the Covid 2019 pandemic. This service had unreal expectations: to be done within single month, to serve millions of requests in a single day of highly classified data, integrations with all banks and dozen of ministries, to be highly secure and resistant to malversations and attacks and with all of the citizen data to be hosted in the country. This was all to be done in military emergency state where most of institutions didn't have regular working schedule and working in severely diminished capacities, unregular working time and 100% remote.

The project is done, as usual, with free and open source technologies, commodity hardware and on premise without using any public cloud except CloudFlare (only for DDOS protection).
The service successfully registered 2M citizens in few hours, and almost all Serbian citizens the next day, without downtime, processing more then 10M requests per day while utilizing 1-3% of each included server resources.