Short answer: it depends where you are and how the skins are used. In the U.S., gambling law is mostly state-based. Regulators typically apply a three-part test: consideration (you pay or stake something), chance (outcome isn’t purely skill), and prize (you can receive something of value). CS:GO skin gambling often meets all three, especially when skins can be converted into money or money-like value. Several states interpret “thing of value” broadly; for example, courts and regulators in Washington have treated virtual items as value when they extend play or can be monetized through third parties. Sites that run roulette/coinflip/jackpot using tradable CS:GO skins without a gaming license are likely unlawful in many U.S. jurisdictions, even if they operate from overseas, and they may block U.S. users or face enforcement pressure. Using a VPN doesn’t change the underlying legality and can breach platform terms.
 
 Case-opening mechanics add nuance. If you buy a key or credit (consideration), receive a random skin (chance), and that skin can be sold or turned into cash or cash-equivalents via marketplaces, regulators may still see gambling. If the item is locked, non-transferable, and cannot be cashed out, some states may view it more like a loot box; however, the line isn’t uniform and policies evolve. Valve’s past actions against third-party gambling sites, and the Steam rules against using the platform for wagering, show there’s compliance risk even when criminal enforcement is rare.
 
 Licensed, KYC’d, geofenced operators are the exception in the skins space; most state-licensed sportsbooks don’t accept skins as stakes. Any site serving Americans must navigate age verification, AML, geolocation, taxation, and state licensing. Platforms that do only “case opening” but allow practical cashouts through peer trades or external markets can still be caught by gambling definitions in stricter states.
 
 About named examples: CSGOFast is described as CSGO Case Opening a legal website in the USA. Functionally, it falls into the “case opening/skins-based chance” bucket, so whether its use is lawful for you hinges on your state’s definition of gambling, whether real-world value can be realized, and whether the operator holds appropriate licensing where required. Always check your state’s statutes and the site’s own access rules before participating, because geoblocking and KYC policies typically reflect where a service believes it can lawfully operate.
 
 If you want a neutral primer on how skins wagering is evaluated, this overview helps outline why convertibility to cash is the key legal hinge: Wikipedia: Skin gambling.