How to connect back-end with front-end using ngnix in Kubernetes

Solved it using this nginx.conf

upstream purser {  server purser.default.svc.cluster.local:3030;}server {  listen 4200;  location /api {    proxy_pass http://purser;  }  location / {    root /usr/share/nginx/html/purser;    index index.html index.htm;    try_files $uri $uri/ /index.html =404;  }} 

and calling backend from frontend using BACKEND_URL = window.location.protocol + '//' + window.location.host + '/api/'

Explanation:Frontend when it requires data from backend calls itself at path /api, nginx finds this path and according to configuration forwards it to backend kubernetes service purser.default.svc.cluster.local:3030 using proxy_pass

@Kaladin your approach was almost there, but I think there is something missing.

What I did was

upstream gateway {  server gateway-cip-service:3000;}server {  listen 80;  location /api {    rewrite /api/(.*) /$1 break;    proxy_pass http://gateway;    proxy_http_version 1.1;    proxy_set_header Upgrade $http_upgrade;    proxy_set_header Connection "upgrade";  }  location / {    root /usr/share/nginx/html;    index index.html index.htm;    try_files $uri $uri/ /index.html;  }} 

The biggest headache was to find out the proxy header upgrade, such a pain.

Consider that in my backend my routes do not have an "api" prefix, that is why I use "rewrite /api/(.*) /$1 break;" to take only whatever that comes after /api/ Otherwise, you can avoid that line of code.