Under the hood, it utilizes the python-etcd3 library, which provides a callback method to listen for changes on keys.

• No boilerplate code is required.
• There is no need to manually define which callback function type needs to be bound.
• It provides a JSON deserializer by default, but you can define your own deserialization logic based on your requirements.
• It supports auto-reconnection with etcd in case of a connection failure.
• You can specify the number of connection retries and the retry delay.
• It applies different deserialization methods to keys if you have mixed key-value pairs.
• It allows for easy addition of new observers to perform desired operations on keys.
• You can remove the parse_engine observer in case of simple key-value pairs.

1. Find the user's zone if they are in the Red, Yellow, or grey zone based on the confirmed case around them.
2. Advise people on what they should do or not if they are in the infected region or not.
3. Show clusters of COVID-19 regions for officials to take the right decisions. And for the public to take appropriate precautions. Officials can
   • Easily identify infected regions, and then impose lockdown and run an awareness campaign.
   • (Local authorities) can take quick and real-time decisions.
   • Identify those regions where no of cases increasing.
4. Show nearest confirmed case and Quarantine center point (address, distance (from user location), and radius range).
5. Show the total no of confirmed cases and no of points in different ranges around the user.
6. Provides WHO (World Health Organization) and National website links for the latest information and some other useful links
   • Myth busters
   • When and how to use masks
   • Advice for public
   • Advocacy
7. Users can also check other regions in case of if they wanna go or someone coming from the infected region based on the result they will take the right decision and appropriate precautions.

REST API module is for mobile application and secured from distributed denial-of-service (DDoS) attack using API rate limiter.

Redis in-memory database is used for the high availability of the application and provides very low latency.

Authentication and Authorization feature for staff members e.g. if multiple laboratories upload confirmed cases of covid19.

Compare to other rate limit algorithms sliding window counter is

1. Avoid spikes (Smooth out brust)
2. Memory efficient

Rate limit strategies allowed in this algorithm

1. N requests per second.
2. N requests per minute
3. N requests per hour

Rate limit HTTP headers allowed in this algorithm

1. X-RateLimit-Limit
2. X_RateLimit_Remaining
3. X-RateLimit-Reset
4. Retry-after