Google added reminder support to Google calendar late last year, but the feature felt oddly incomplete without full support for reminders on the web. That's a thing now, so you can create and manage reminders in Google Calendar on the web. It's not showing up for me just yet, but everyone should see reminders on the web soon.
Reminders in Google Calendar will work across devices, and now that includes your browser. Reminder support is also baked into Keep and Inbox. Whether created on the web interface or in an app, reminders will show up on your Google Calendar everywhere and carry over between days until you mark them as done. Reminders are different from events in that they are private, even if you have your calendar shared with someone.
Google says the rollout of reminders on the web will start within two weeks, and should be complete in 1-3 days from the start date.