SMSTunnel for Google Calendar

1. 1. Install the SMSTunnel app from Google Play on your Android phone and sign in.
2. 2. In your dashboard, open Apps → Add an app, pick Google Sheets, Forms or Calendar, name it (for example "Google Calendar") and click Create the key.
3. 3. Copy the key right away: it's shown only once. You can stop or delete the app there anytime, and Google Calendar can't send texts anymore.

Get the steps with your key in them

It opens Add an app with Google Sheets, Forms or Calendar picked. Once the key is made, the dashboard shows every step and command with the key already filled in, ready to copy.

Make one key per spreadsheet or form, so you can stop one without touching the others.

Ready-made copies (Make a copy) are coming soon. Pasting the code works today and takes a few minutes:

1. 1. Make a new spreadsheet for it: the script lives in a spreadsheet, which keeps the log and, if you want, your guests' numbers. Then open Extensions → Apps Script.
2. 2. Make the same files as the template's folder on GitHub (apps-script/calendar-reminders) and paste each one's content:
   • SmsTunnel, SmsTunnelKit and Code: script files (+ → Script; the editor names them .gs);
   • Setup: an HTML file (+ → HTML).
3. 3. Open Project Settings (the gear), tick Show "appsscript.json" manifest file in editor, open appsscript.json and replace it with the template's.
4. 4. Save, go back to your spreadsheet and reload it. The SMSTunnel menu shows up after a few seconds (reload the page once if it doesn't).

1. 1. Choose SMSTunnel → Set up. Google asks you to allow the script the first time (see below).
2. 2. Paste your key, click Check, choose the phone that sends the texts, fill in the rest and click Save and turn on.
3. 3. Send yourself a test: SMSTunnel → Send me a test reminder.

The setup dialog has the same test button, so you can try your text before saving.

Remind me before each event

A text to your own numbers (up to 5, one text each) 10, 15, 30 or 45 minutes, 1 to 12 hours, or a day before each event in the calendars you choose. Optionally only events whose title has a word you choose ("dentist, call"). All-day events are left out unless you include them (they then count as starting at the hour you choose, 8:00 by default).

Text me my agenda every day

One text each day at the hour you choose: "Today, Mon, Nov 2: 9:00 AM Dentist, 2:00 PM Call with Ana". Days with nothing planned are skipped unless you say otherwise.

Remind the people in your events

• For appointments. The person's number comes from a line in the event's description that starts with a word you choose and a colon, such as SMS: +1 415 555 0123 or Phone: 0722 123 456, or from the Phone numbers sheet (Email, Phone, Name) for guests you invited. The word can be in any language (Téléphone:, Telefon:).
• Other numbers in a description, such as a video call's dial-in line, are never used.
• Only events you created count, unless you untick Only events you created: otherwise an invitation from someone else could put a number in its description and choose who gets a text from your phone.
• Reminders to people go out only between the hours you choose (8:00 to 21:00 by default), at most 10 people per event. Only text people who asked for these reminders.

Texts can use {Title}, {Date}, {Time}, {Location}, {Calendar}, {In} ("in 15 min") and, for people, {Name}. Under More settings: the country code for numbers written without one, how dates and times look in texts, and at most how many texts go out per check.

• Never twice. Each text is recorded (event, start time and number) in a hidden SMSTunnel sent sheet. If an event moves, its new time gets one new text. Declined events are left out.
• How often it checks: every 5 minutes when you want a reminder 10 or 15 minutes before (so two checks fall inside the time you chose), every 10 minutes up to an hour, every 15 minutes otherwise or for the agenda, and every hour when only people get reminders. That stays well within Google's daily limits.
• The log: every text, and every event that could not be texted, is listed in the SMSTunnel log sheet (the last 2000 lines).

• The key stays in the script's user properties: only you can read it, and it is never written to a cell, a note or a log. The setup dialog shows only its last 4 characters.
• Who can change the script: everyone with edit access to the spreadsheet can edit its script, and a trigger runs with the permissions of the person who set it up. Give edit access only to people you trust.
• What leaves your file: for each text, the number and the text go to SMSTunnel and to your phone. Logs stay in your spreadsheet. Nothing is sent anywhere else.
• Safe writes: anything SMSTunnel writes to a cell (an event title from someone else's invite, a reason from the server) is written as text, never as a formula.
• Stop everything by deleting the key under Apps in your SMSTunnel dashboard.

Does it cost anything?

The template is free, and Google Apps Script is free with any Google account. The texts count against your SMSTunnel plan, and your mobile plan applies to the texts your phone sends.

Whose number do people see?

Yours. The texts leave your own phone, from its SIM, like a text you type yourself. Replies come back to your phone.

What if my phone is off?

The text waits and goes out as soon as your phone is back online.

Will it text a number twice?

No. It writes down each text it sends in a hidden list and checks it before each text. If an event moves, its new time gets one new text.

Where is my key kept?

In the script's own private storage for your account, which only you can read. It never goes into a cell or a log. Delete the key under Apps in your dashboard and every text stops at once.

Does it work with Google Workspace accounts?

Yes, with personal Google accounts and Google Workspace accounts. Workspace accounts get higher daily limits from Google.