Most "best reminder app" roundups are written for people managing a household, not a codebase. If you spend your day in a terminal, an editor, and increasingly an AI assistant, the criteria are different: does it fit your existing workflow, or does it demand yet another tab you have to remember to check?
The default choice for a reason — mature, cross-platform, and genuinely good at general task management with projects, labels, and filters. The catch for reminders specifically: reminders are a Pro-only feature, and Pro runs $5–7/month billed monthly, closer to $60/year annually. If you mainly want lightweight reminders rather than full project management, you're paying for a lot you won't use.
Includes reminders on the free plan — a real advantage over Todoist if reminders are the primary use case — and adds habit tracking, a Pomodoro timer, and a full calendar view on Premium at roughly $36/year, notably cheaper than Todoist Pro. Good general-purpose choice if you want task management and reminders in one app and don't need developer-specific tooling.
Free, built in, and syncs cleanly across iPhone, iPad, Mac, and Apple Watch via iCloud. The dealbreaker for a lot of developers: no official app for Android or Windows, and no real API for scripting. Fine as a personal, Apple-only utility; not built for automation.
A different model entirely — you email a special address like tomorrow@followupthen.com and it emails the reminder back at that time. Genuinely clever for email-based follow-ups, works with any email client, free tier is generous. It's not a task manager and isn't trying to be one — it's a single, sharp tool for one job.
Built specifically for the terminal-and-AI-assistant workflow: an MCP server for Claude Desktop, a CLI (rem "call dentist tomorrow 3pm"), and a REST API, all backed by the same account and the same natural-language parsing. The free tier covers 10 active reminders; Pro ($4/mo or $36/yr) removes the cap and adds full RRULE recurrence and API access. If your reminders workflow starts in a chat with Claude or a terminal prompt rather than a mobile app, this is the one built for that.