SMS appointment reminders for your own calendar, whether iCloud, Nextcloud, or NAS.
CalDAV is the open standard that iCloud, Nextcloud, Synology, mailbox.org, and many other calendars use to sync. LOX24 plugs in there: if a mobile number with a hashtag is in the appointment, the SMS is sent automatically. Your calendar stays where it is, even on your own server.
- Any CalDAV calendar
- No Google or Microsoft account needed
- from 7.5 cents per SMS
- §Servers in Germany
From CalDAV to SMS reminder in three steps
From calendar entry to SMS
OPEN STANDARD
01 · ACCESS
Set up CalDAV access
In the LOX24 web interface, enter your calendar's CalDAV address and login credentials. Then write your reminder text with placeholders for date and time, and choose how far in advance the SMS is sent.
02 · ENTRY
Add the phone number with #
In the calendar app of your choice, whether Apple Calendar, Thunderbird, the Nextcloud web interface, or an Android app with CalDAV sync: Add the customer's number to the appointment with a hashtag, for example #+4915112345678.
#
+4917012345678
03 · SENDING
The SMS goes out automatically
As soon as the appointment is on your CalDAV server, LOX24 finds the hashtag and sends the confirmation and reminder at the scheduled time. Appointments without a hashtag are left untouched.
PER SMS
from 7.5 cents
These calendars speak CalDAV
Apple iCloud
Nextcloud
Synology Calendar
mailbox.org
Your own server
Apple iCloud
Nextcloud
Synology Calendar
mailbox.org
Your own server
Stay independent
Your calendar, your infrastructure, your SMS
Many reminder services require a Google or Microsoft account. With CalDAV, that's not necessary: LOX24 reads appointments directly from the calendar you already use, even if it runs on your own server. You don't switch systems, and you don't hand over control of your calendar.
Who CalDAV reminders are especially suited for
For businesses that deliberately choose not to manage their appointments with Google or Microsoft, but within the Apple ecosystem or on their own infrastructure:
- Medical practices and therapists with Mac and iPhone who manage their appointments in Apple Calendar via iCloud
- Law firms and tax consultancies that use Nextcloud as a privacy-friendly alternative to cloud services
- Businesses with a Synology or QNAP NAS whose calendar runs in their own office
- Teams using mailbox.org, Posteo, or another European email provider with a calendar
- Clubs, schools, and educational institutions with self-hosted groupware
- IT service providers and agencies that schedule client appointments in open-source tools
Video: SMS reminders from your calendar
Pricing
What an SMS reminder from your CalDAV calendar costs
S plan
Top-up from €40
8cents
50 appointments per month4,00 €
M plan
Top-up from €145
7,9cents
200 appointments per month15,80 €
L plan
Top-up from €400
7,5cents
500 appointments per month37,50 €
A missed treatment or an empty consultation slot usually costs more than a hundred reminders.
All prices are net per SMS of up to 160 characters to Germany, using the Direct shipping method. With the Economy and Pro shipping methods, a reminder costs 7.5 cents (S plan) to 6.9 cents (XL plan). If you also send an appointment confirmation, the cost per appointment doubles.
Other calendars
Do you work with Google or Outlook?
LOX24 offers dedicated integrations for Google Calendar and Outlook. The hashtag method stays the same; only the connection to the calendar is different.
Go to the Outlook SMS add-in
OUTLOOK
Go to the new Outlook add-in
MICROSOFT 365
Privacy
What LOX24 sees via CalDAV
LOX24 signs in with the credentials you provide and reads only the calendars you share. There, LOX24 looks for phone numbers with a hashtag. Only what you include as a placeholder in your template goes into the SMS.
Especially when your calendar runs on your own hardware, you keep control of your data. LOX24 processes SMS on servers in Europe, under telecommunications secrecy and with a data processing agreement (DPA).
Your control at a glance
- Read-only access via CalDAV
- Only to the calendars you connect. You can disconnect at any time in LOX24 or by revoking the password with your calendar provider.
- Shared calendars only
- You decide which calendars LOX24 may read. All others stay invisible.
- Sent only with
# - An SMS is created only if the appointment contains a phone number with a hashtag.
- Your template determines the content
- Description or notes only end up in the SMS if you insert the placeholder for them.
- Revoke access at any time
- If you change or revoke the password, the connection is cut off immediately.
Our tip: With iCloud, Nextcloud, and many other services, you create a separate app password just for LOX24. That way, you never give out your main password and can revoke access selectively. A separate calendar just for customer appointments also keeps private entries out of the picture.
Good reasons
Why businesses using CalDAV choose LOX24
CalDAV users have usually made a conscious choice for independence. LOX24 fits that: a European provider, servers in Europe, no ties to big platforms, and no software to install.
FAQ
Questions about CalDAV and SMS reminders
What is CalDAV?
CalDAV is an open standard that calendar apps and calendar servers use to exchange appointments. It is used by iCloud, Nextcloud, Synology Calendar, and mailbox.org, among others. LOX24 uses this standard to find appointments that include a phone number.
What credentials does LOX24 need?
Your calendar's CalDAV address, plus your username and password. For iCloud and Nextcloud, we recommend creating a separate app password for LOX24, which you can revoke at any time.
How do I add the phone number to the appointment?
With a hashtag directly before the number and no spaces, in international format as #+4915112345678 or in national format as #015112345678.
Which appointment details can I use in the SMS?
Title, date, time, end time, location, description, and the calendar name. You decide which of these appear in the SMS in your template.
Does this also work with a self-hosted server?
Yes, as long as your CalDAV server is reachable from the internet, such as a Nextcloud or a NAS with a shared calendar. You can create a separate template for each connected calendar.
Does LOX24 see all my appointments?
LOX24 only reads the calendars you share and only reacts to appointments with a phone number and hashtag. You can further limit access with a dedicated calendar for customer appointments and an app password.
How much does a reminder cost?
An SMS to Germany costs between 6.9 and 8.0 cents at LOX24, depending on the shipping method and pricing tier. There is no base fee and no contract term.
Can customers reply to the SMS?
Yes. With the Economy shipping method, replies from Germany and Switzerland reach you by email free of charge. With your own phone number, replies also arrive in your LOX24 inbox.
I use Google Calendar or Outlook. Does it work with those too?
Yes. LOX24 offers dedicated integrations for Google Calendar and Outlook. The hashtag method works the same way there.
Can I try it for free?
Yes. After you register with LOX24 for free, you get 50 cents of starting credit, enough for your first test reminders.
Connect and test your CalDAV calendar
Create an account, add your CalDAV access, and enter your first appointment with a hashtag. With 50 cents of starting credit, no contract.
Sign up for freeYour calendar. Our SMS.
Add your CalDAV access and send your first reminder with 50 cents of starting credit. No base fee, no contract.
OPEN STANDARD
NO BASE FEE
50 CENTS STARTING CREDIT
SERVERS IN EUROPE