Which country offers the fastest post study work path for an MS CS graduate who eventually wants to start a company?

If your real goal after an MS in Computer Science is to start your own company, you should look closely at the United Kingdom and Canada rather than the United States. Both countries let you work as a self-employed founder immediately after graduating, while the US post study route is built around a traditional employer relationship that makes founding a startup much harder.

Post Study Visa Comparison for Future Founders

Why the UK and Canada Lead

• The UK Graduate Visa removes the usual buffer between graduating and launching a business, since you do not need a corporate sponsor and can operate as a founder straight away, then transition into the Innovator Founder Visa, which has no minimum capital requirement.
• Canada's Post-Graduation Work Permit is fully open, so you can legally incorporate and run your startup while on it, and if you secure backing from a designated Canadian venture fund or incubator, the Start-up Visa fast-tracks you to permanent residency.
• The US STEM OPT extension technically allows entrepreneurship, but only if you set up a formal board that holds hiring and firing power over you, which adds significant legal complexity most new founders want to avoid.

My Advice

If speed and freedom to build immediately matter most, choose the UK for its zero-friction self-employment rules right out of graduation. If you would rather secure long-term stability before pitching investors, lean toward Canada, since its path to permanent residency removes visa pressure from your fundraising conversations entirely. Either way, start researching the specific founder visa requirements during your final year, not after you graduate.