**ReCodEx** is designed to be very modular. **WebApp** + **File Server** are one instance of the application. They contain almost all logic of the app including _user management and authentication_, _storing and versioning tasks_, _counting and assigning points_ to users etc. One instance of the app can be connected to one or more **Workers** and one **Worker** can be connected to more instances of the **WebApp**. **Worker** is connected with **WebApp** through messaging queue.
**ReCodEx** is designed to be very modular. **WebApp** is considered to be frontend part of whole system while all other parts/services are considered to be backend part. **WebApp** contains almost all logic of the app including _user management and authentication_, _storing and versioning files_ (through connection with **Fileserver**), _counting and assigning points_ to users etc. **WebApp** is connected with **Broker**, **Fileserver** and partially with **Monitor**. **Broker** is essential part of whole architecture and can be marked single point of failure.
Almost whole communication goes through **Broker** and `ZeroMQ` messaging middleware. When **WebApp** wants to execute submission then all datas are handed over to **Worker** through **Broker**, similar situation is with progress state which start in **Worker** goes through **Broker** then pass **Monitor** and end up in **WebApp**. Only part of communication, which does not include **Broker**, is communication with **Fileserver** which is realized through `HTTP` commmunication. This communication can be initiated by **WebApp** or by **Worker**, other services have no access to **Fileserver**. Summarize of above stated can be found in overall architecture image (green arrows = `HTTP` communication, red arrows = communication through `ZeroMQ`).