Press F9 while in Roblox Studio or the Roblox Player to open the Developer Console. On Mac, use Fn+F9 if function keys require the Fn modifier. The console appears as a docked window showing real-time logs, errors, warnings, and performance metrics. The console has multiple tabs. The Log tab displays script print statements and runtime errors with stack traces. The Memory tab shows current memory usage broken down by category, helpful for spotting leaks in large games. The Network tab reveals data sent and received, ping times, and packet loss—critical when diagnosing lag or synchronization issues. The Server Stats tab (visible to developers in Studio or published games they own) tracks server heartbeat, physics steps, and frame time. For script debugging, use print() statements liberally in your Lua code to output variable values and execution flow to the console. When errors occur, the console provides the script name, line number, and error type, which speeds up troubleshooting compared to guessing. Warnings about deprecated functions or API changes also surface here before they break your game in future updates. If you're testing a published game and own it, you'll see both client and server logs. Regular players only see client-side output, so server-side print statements won't appear for them. This split matters when isolating whether a bug originates from client scripts (LocalScript) or server scripts (Script). At Ottawa SEO, we occasionally work with clients running Roblox experiences for brand engagement or virtual events. We check the console during QA to verify analytics tracking scripts fire correctly and that third-party integrations (like webhooks to external dashboards) don't throw silent errors. The console is non-negotiable for any Roblox developer serious about stable, performant experiences. If F9 doesn't work, check your keyboard settings or try right-clicking the Roblox window title bar and selecting Developer Console from the menu, though that method isn't available in all contexts.