During App development, the applications are usually hosted on the local Development servers and QA Servers in most of the companies. These servers are not accessible from exernal networks such as the Internet either due to network configurations(filtering by proxy or VPN) or due to firewall policies.
Therefore, in such scenarios, the Cloud Execution Environments in Testsigma such as Testsigma Lab, Sauce Labs, and BrowserStack cannot access these Local Application URLs directly for Testing.
Taking the security concerns into consideration, Testsigma has implemented Hybrid Executions.
Hybrid Execution allows you to test the locally hosted Application using Testsigma without the use of VPNs, setting up tunnels, or whitelisting any of your IPs.
Hybrid Execution allows you to run the Tests on your chosen Test Machines in your local network itself and doesn't need to use the Cloud Environments.
Please check the below article for more details - How to execute Web Application tests in Hybrid model?
You may also check the following article for other additional options - How to execute tests for locally hosted applications?