Send subscription renewal reminders via Telegram with Supabase

Description

Subscription Renewal Reminder – Telegram & Supabase

This workflow tracks upcoming subscription expiry dates stored in Supabase and automatically sends personalized renewal-reminder messages to each customer via Telegram. It is designed to be triggered by an HTTP Webhook (manually or on a schedule) and ensures that customers are notified a configurable number of days before their subscription lapses.

> Community Template Disclaimer
> This is a community-contributed n8n workflow template. It is provided “as-is” without official support from n8n GmbH. Always test thoroughly before using in production.

Pre-conditions/Requirements

Prerequisites
n8n instance (self-hosted or n8n.cloud)
Supabase project with a subscriptions table
(id, customer_name, expiration_date, telegram_chat_id, notified)
A Telegram Bot created via @BotFather
Outbound HTTPS access from n8n to api.telegram.org and your Supabase project REST endpoint

Required Credentials
Supabase Service Role Key** – Full access for reading/writing the subscriptions table
Telegram Bot Token** – To send messages from your bot
n8n Webhook URL** – Auto-generated when you activate the workflow

(ScrapeGraphAI API Key is *not* required for this non-scraping workflow.)

Specific Setup Requirements
| Environment Variable | Example Value | Purpose |
|----------------------|--------------|---------|
| SUPABASE_URL | https://xyzcompany.supabase.co | Base URL for Supabase REST API |
| SUPABASE_KEY | eyJhbGciOiJI... | Service Role Key |
| TELEGRAM_TOKEN | 609012345:AA... | Bot token obtained from BotFather |
| REMINDER_DAYS | 3 | Days before expiry to notify |

How it works

This workflow tracks upcoming subscription expiry dates stored in Supabase and automatically sends personalized renewal-reminder messages to each customer via Telegram. It is triggered by an HTTP Webhook (manually or via external scheduler) and ensures that customers are notified a configurable number of days before their subscription lapses.

Key Steps:
Receive Trigger (Webhook)**: External call fires the workflow or an internal Cron node can be added.
Set Static Parameters**: The Set node calculates “today + REMINDER_DAYS”.
Query Supabase**: Fetch all subscriptions expiring on or before the calculated date and not yet notified.
Branch Logic (If node)**: Check if any subscriptions were returned.
Loop & Dispatch (Code + Telegram nodes)**: Iterate over each customer row, compose a message, and send via Telegram.
Flag as Notified (Supabase Update)**: Update each processed row to prevent duplicate reminders.
Respond to Webhook**: Return a concise JSON summary for logging or downstream integrations.

Set up steps

Setup Time: 15–20 minutes

Create Telegram Bot
a. Open Telegram and talk to @BotFather → /newbot
b. Copy the given bot token; paste it into n8n Telegram credentials.

Prepare Supabase
a. Create a table named subscriptions with columns:
id (uuid), customer_name (text), expiration_date (date),
telegram_chat_id (text), notified (bool, default false)
b. Obtain the Service Role Key from Project Settings → API.

Import the Workflow
a. In n8n, click Templates → Import and select “Subscription Renewal Reminder – Telegram & Supabase”.
b. Replace placeholder credentials in the Supabase and Telegram nodes.

Define Environment Variables (Optional but recommended)
Add SUPABASE_URL, SUPABASE_KEY, TELEGRAM_TOKEN, and REMINDER_DAYS in Settings → Environment Variables for easy maintenance.

Activate the Workflow
Copy the production webhook URL and (optionally) set up a cron job or n8n Cron node to hit it daily.

Node Descriptions

Core Workflow Nodes:
Webhook** – Entry point; triggers the workflow via HTTP request.
Set (Calculate Target Date)** – Defines targetDate = today + REMINDER_DAYS.
Supabase (Select)** – Retrieves expiring subscriptions that haven’t been notified.
If (Rows > 0?)** – Determines whether to continue or exit early.
Code (For-Each Loop)** – Iterates through each returned row to send messages and update status.
Telegram** – Sends a personalized renewal reminder to the customer’s chat.
Supabase (Update)** – Flags the subscription row as notified = true.
Respond to Webhook** – Returns a JSON summary with counts of sent messages.
Sticky Notes** – Inline documentation for maintainers (non-executable).

Data Flow:
Webhook → Set → Supabase (Select) → If → Code → Telegram → Supabase (Update) → Respond to Webhook

Customization Examples

Send Slack Notifications Instead of Telegram
// Replace Telegram node with Slack node
const message = Hi ${item.customer_name}, your subscription expires on ${item.expiration_date}.;
return [{ text: message, channel: item.slack_channel_id }];

Notify 7 Days & 1 Day Before Expiry
// In Set node
items[0].json.reminderOffsets = [7, 1]; // days
return items;

Data Output Format

The workflow outputs structured JSON data:

{
"totalSubscriptionsChecked": 42,
"remindersSent": 13,
"timestamp": "2024-05-27T09:15:22.000Z"
}

Troubleshooting

Common Issues
No messages sent – Check the If node; ensure REMINDER_DAYS is set correctly and the Supabase query returns rows.
Telegram error 403 – The user hasn’t started a chat with your bot. Ask the customer to click “Start” in Telegram.

Performance Tips
Batch database updates instead of row-by-row when dealing with thousands of records.
Cache Supabase responses if you expect multiple workflows to query the same data within seconds.

Pro Tips:
Use the Cron node inside n8n instead of external schedulers for a fully self-contained setup.
Add an Email node after the Telegram node for multi-channel reminders.
Store template messages in Supabase so non-developers can update wording without editing the workflow.