# Custom Data

Custom data is stored as key/value. All values are stored as strings but we do convert boolean values and values from keys ending in `_at` to datetime at output. Custom data can be added to booking, person, service, resource and event. If you are using our standard booking site and would like to store custom data to a new booking please see [the custom forms documentation](https://github.com/makeplans/makeplans-custom-forms) for details on how to customise the booking form.

*Warning*: Custom data is stored as one attribute. **All** keys and values must be present when updating. If a booking has stored `custom_data` as `makeplans_is=awesome` and you want to add `signup=now` then you need to include both `makeplans_is` and `signup` with their values.