API web infrastructure

Question

I am building an API infrastructure layout and would like to see your opinions, as well as scalability ideas and concepts applied.

I won’t go into too much detail of internal infrastructure, behavior and functionality.

Currently the layout for the project consists of the image below:

The project has a heterogeneous system that requires other Apis to work. All act together, making access fully transparent to users. Most often Apis have replicated data for query validations in the database. In all there are 4 separate Apis, each API has been dedicated to doing specific operations:

API 1 - Moderação

    * Roda em conjunto uma interface WEB construída em Laravel para moderação de dados enviados dos dispositivos mobile e outras plataformas
    * Integra dados na API 2
    * Recebe requisições de dispositivos e outras plataformas
    * Recebe status de pagamentos de API's de terceiros
    * Envia imagens para API 4

API 2 - Integração

    * Recebe dados moderados da API 1
    * Recebe requisições de dispositivos mobile
    * Integra alguns dados necessários para API 3

API 3 - Processamento de dados e gerenciamento

    * Recebe dados da API 2
    * Processa informações a nível de Scripts
    * Recebe requisições de dispositivos mobile

API 4 - Gerenciamento de imagens

    * Recebe imagens da API 1
    * Retorna imagens para dispositivos e outras plataformas

As it is a huge data processing, it was designed in a non-central structure to meet the demannda needs of service availability, was first thought of the layout presented in the image above where it is possible to perform the integration in parallel between the Apis and balance both the data processing and the access to the servers that host the Apis.

Therefore, I have doubts regarding the maintenance of the code and also the applicability of this idea and I would like to know if I can follow this way, if I am on the right track and if it is really feasible to follow this configuration. I adopted this idea thinking of a really high number of accesses, considering the availability of the services involved where if one stops, the system does not stop altogether.

But I have seen many ideas regarding putting this whole structure running on a single server with a single API.

I would also like to point out that I intend to start with Digital Ocean servers and whether they would support a simultaneous amount of large access.

Technologies used:

Postgresql

• All queries, updates and Inserts run at the database level where functions have been created for that purpose

• php is only in charge of calling the functions.

Laravel

• Rotate the web moderation panel
• Api wheel

phpSlim Framework (php7)

• Run the other Apis