Getting a JSON with no data between MongoDB Container and TS+Express Container

Question

I have a RestAPI (TypeScript+Express) which connects to a MongoDB collection, if both of them are running in Docker's containers and I try to get data through an endpoint it retuns a JSON with no data, if I run the RestAPI in bare metal (Ubuntu) I get the expected data from MongoDB container. So far I've checked:

1. expected ports in Listen Mode (passed)
2. no firewall rules blocking communication (passed)
3. No authentication required (passed)
4. Status 200 and JSON generated (passed)

Below you can find an example of data retrieved (API running in bare metal):

The same example but this time the API running on a Docker's container:

The same endpoint with more details:

I've also tried to login to the API container and run the endpoint but still no data. One important fact is the connection parameters are managed though .env file; checking the logs file from each container everything seems to be normal.

Here you can find the Dockerfile of my API:

FROM node:18-alpine AS builder

WORKDIR /295fullstack

COPY ./backend/*.json  ./

RUN apk add yarn
RUN apk add bash
RUN apk add curl

RUN yarn install --frozen-lockfile

COPY ./backend/. .

RUN yarn add dotenv

COPY ./backend/.env.template ./.env
RUN sed -i '1iNODE_ENV=development' ./.env
RUN sed -i 's/DATABASE_URL=.*$/DATABASE_URL=mongodb:\/\/mongodb:27017/' ./.env
RUN sed -i 's/DATABASE_NAME=.*$/DATABASE_NAME=TopicstoreDB/' ./.env
RUN sed -i 's/HOST=.*$/HOST=0.0.0.0/' ./.env
RUN sed -i 's/PORT=.*$/PORT=5000/' ./.env

#adding a script for loading env with Typescript
RUN sed -i '/"scripts": {/a\    "start:with-env": "ts-node -r dotenv/config src\/app",' package.json

EXPOSE 5000

CMD ["yarn", "run", "start:with-env"]

And this one is for the MongoDB:

FROM mongo:7.0.2

MAINTAINER @heftamayo

COPY db/mongo-initutf8.js /docker-entrypoint-initdb.d/

EXPOSE 27017

CMD ["mongod", "--bind_ip_all", "--port", "27017"]

Finally, these are the services from the docker-compose:

version: "3.8"

services:
  db:
    container_name: mongodb
    restart: always
    build:
      context: .
      dockerfile: Dockerfile.mongo
    ports:
      - "27017:27017"
    volumes:
      - mongodb_data:/data/db
    #command: mongod --bind_ip_all
    healthcheck:
      test: ["CMD", "bash", "-c", "mongosh --eval 'db.adminCommand(\"ping\")'"]
      interval: 10s
      timeout: 5s
      retries: 3
      start_period: 30s
    networks:
      network:
        ipv4_address: 192.168.20.7

  backend:
    container_name: 295fsbe
    restart: unless-stopped
    depends_on:
      db:
        condition: service_healthy
    image: hftamayo/295fs_be:stable-1.0.0
    ports:
      - "5000:5000"
    networks:
      network:
        ipv4_address: 192.168.20.9

volumes:
  mongodb_data:

networks:
  network:
    driver: bridge
    ipam:
      config:
        - subnet: 192.168.20.0/24

So basically I ran out of ideas how to debug this, surely the issue is in the API's container but honestly I don't get it, your suggestions and comments will be valuable to find what's going on with this.

Thanks a lot