Another day, another problem. I need to replicate the production deployment, which consists of multiple services running on different domains. I cannot do that purely relying on localhost because I must test cookies and local storage behaviour between redirects. Modifying the /etc/hosts file alone does not help because the port number is not supported. It seems that hosts file changes should be accompanied by some locally running reverse proxy to map domains to ports correctly.

Hosts file

One way of doing it is to start with the hosts file and intercept your service domain name resolution to point to localhost:

127.0.0.1 first.service.com
127.0.0.1 second.service.com
127.0.0.1 third.service.com

Apache server

Then configure your Apache server. Add virtual hosts to the config:

# additional config for local dev
<VirtualHost *:80>
    ServerName first.service.com
    ProxyPass / http://localhost:8080/
    ProxyPassReverse / http://localhost:8080/
</VirtualHost>
<VirtualHost *:80>
    ServerName second.service.com
    ProxyPass / http://localhost:8081/
    ProxyPassReverse / http://localhost:8081/
</VirtualHost>
<VirtualHost *:80>
    ServerName third.service.com
    ProxyPass / http://localhost:8082/
    ProxyPassReverse / http://localhost:8082/
</VirtualHost>
# end aditional config

If you’re on macOS Big Sur

• Hosts file is in /etc/hosts
• Apache config is in /etc/apache2/httpd.conf
• Test your Apache config with apachectl configtest
• Enable/uncomment proxy_module and proxy_http_module in Apache config
• Enable/uncomment Include /private/etc/apache2/extra/httpd-vhosts.conf in Apache config - this is where I’ve added additional virtual hosts
• Flush DNS sudo dscacheutil -flushcache and sudo killall -HUP mDNSResponder

Clear HSTS cache

If your services are using https scheme then most likely your browser has cached
HTTP Strict Transport Security requirement, meaning that it’ll not use insecure http scheme locally. If it is not cleared then your browser will not be able to reach the locally running applications on http scheme and will keep using https which will fail to load the site due to above config.

On Firefox open all browsing history, select your site, right click and choose “Forget about this site”.