Best free distraction blocker tools

There are roughly 40-60 actively marketed distraction blocker tools across iOS, Android, and web, but only 5-8 have meaningful user bases. The common failures are brutal: apps that block too aggressively and feel punitive, freemium models that cripple core features after day two, and tools that don't sync across your actual work devices (phone + laptop + tablet). Most users abandon these within a month because they either work too hard (friction kills adoption) or not hard enough (you just toggle them off). The real gap isn't in blocking—it's in intelligent time-awareness. Tools don't adapt to your actual peak focus hours, your meeting schedules, or context (coding vs. email vs. deep work). A founder shipping here should obsess over: (1) smart defaults that feel automatic, not forceful, (2) integration with calendar/Slack so blocking matches reality, not arbitrary rules, and (3) a design that makes disabling the blocker harder than just letting it work. The demand is real—productivity is a $50B+ category and distraction management is table-stakes for remote workers—but the execution bar is low.