Use Opus One in your browser at opusoneapp.com. Sign in with the same Apple ID you use on your iPhone, iPad and Mac, and your daily and master tasks, categories, notes and daily notes appear instantly. Changes you make on the web sync with your other devices through iCloud.
Google Calendar (optional, web app only)
In the web app you can connect your Google Calendar in Settings → Calendars. Opus One then shows your Google events next to your tasks, lets you create and edit events, and lets you schedule a task by dragging it onto the timeline.
To do this, Opus One asks Google for two permissions: to see the list of your calendars, and to view and edit events on your calendars. We use this access only for this feature, and you can disconnect at any time. See our Privacy Policy for how Google data is handled.
English 
Spanish 