Introduction: The Challenge of Time Management in Tax Filing Operations

The tax filing season is one of the busiest periods for tax professionals and accounting staff. A multitude of tasks, including client requests, document collection and verification, tax return preparation, and submission to tax authorities, pile up. Each of these tasks has a deadline, and missing even one can lead to a loss of client trust or penalties. Traditional task management methods often involve significant time spent on manual reminder setting and frequent progress checks. To address this inefficiency and improve the accuracy and speed of tax filing operations, building an automated notification system using Google Apps Script (GAS) is an effective solution. This article provides a comprehensive guide, explained in an easy-to-understand manner for beginners, on how to use GAS to automatically send daily notifications about tax filing deadlines and outstanding tasks to business chat tools like Chatwork and Slack.

Basics: Understanding GAS, Chatwork API, and Slack API

To fully grasp this automated notification system, it’s essential to understand the underlying technologies.

What is Google Apps Script (GAS)?

Google Apps Script (GAS) is a cloud-based scripting language based on JavaScript, used for integrating and customizing Google Workspace applications (such as Gmail, Google Sheets, Google Drive, etc.). Its key advantage is that it allows you to write and execute code directly in a web browser without any complex environment setup. This makes it relatively easy to implement sophisticated automation, such as triggering a message to Chatwork or Slack based on a task list managed in Google Sheets.

What is the Chatwork API?

The Chatwork API is an interface that allows external applications to interact with Chatwork’s functionalities. By using the API, you can programmatically send messages, create tasks, and retrieve information. In the context of tax filing task notifications, GAS calls the Chatwork API to automatically post reminder messages to a designated chat room.

What is the Slack API?

Similarly, the Slack API provides an interface for external applications to control Slack’s features. It supports a wide range of operations, including sending messages, posting to channels, and retrieving user information. By utilizing the Slack API from GAS, you can automatically deliver notifications related to tax filing to specific Slack channels. Like the Chatwork API, it requires authentication information such as API keys or tokens.

Detailed Analysis: Steps to Build an Automated Notification System with GAS

This section will delve into the specific steps for constructing the system. We will assume the use of Google Sheets as the central hub for task management, with GAS reading from it and sending notifications to Chatwork or Slack.

Step 1: Prepare a Google Sheet for Task Management

First, create a Google Sheet to manage your tax filing tasks. It is recommended to include at least the following columns:

• Task Name: Specific description of the work (e.g., “Prepare Financial Statements for Company X”, “Review Receipts for Client Y”)
• Assignee: The person responsible for the task
• Due Date: The deadline for task completion (date format)
• Status: The current state (e.g., Not Started, In Progress, Completed)
• Notification Flag: A flag to indicate if the task has been notified (e.g., “Notified”, “Pending”)

For example, assign Column A for Task Name, Column B for Assignee, Column C for Due Date, Column D for Status, and Column E for Notification Flag. Ensure the Due Date column is formatted as a date to facilitate easy date comparisons in GAS.

Step 2: Configure Chatwork or Slack API Settings

Chatwork API Configuration

To receive notifications in Chatwork, you need an API token. Obtain this by navigating to “My Page” → “API Settings” in Chatwork. This token will be required when GAS calls the Chatwork API. You also need to identify the ID of the chat room where you want to send notifications. The room ID is the numerical part found in the Chatwork URL (e.g., the XXX in https://www.chatwork.com/#!ridXXX).

Slack API Configuration

For Slack, using Incoming Webhooks is the most common method. Go to your Slack workspace’s settings, navigate to “Apps” → “Custom Integrations” → “Incoming Webhooks”, and select the channel where you want to send notifications. Once configured, a unique Webhook URL will be generated. GAS will use this URL to send messages.

Step 3: Create the Google Apps Script (GAS) Code

Now, let’s create the GAS code. Open your Google Sheet, go to “Extensions” → “Apps Script” to access the script editor. Below are conceptual outlines of sample code for sending notifications to Chatwork and Slack respectively.

Conceptual GAS Code for Chatwork Notification

This code reads the spreadsheet, identifies tasks due today or tomorrow, or tasks that are not yet completed, and sends a message via the Chatwork API.

function sendChatworkNotification() {

  const ss = SpreadsheetApp.getActiveSpreadsheet();

  const sheet = ss.getSheetByName("TaskList"); // Specify your sheet name

  const data = sheet.getDataRange().getValues();

  const today = new Date();

  today.setHours(0, 0, 0, 0);
  const tomorrow = new Date(today);

  tomorrow.setDate(today.getDate() + 1);
  let message = "【Tax Filing Reminder】\n";

  let tasksFound = false;
  for (let i = 1; i < data.length; i++) { // Skip header row

    const row = data[i];

    const taskName = row[0];

    const deadline = new Date(row[2]); // Due Date column

    const status = row[3]; // Status column

    const notified = row[4]; // Notification Flag column
    // Tasks due today or tomorrow, or not completed, and not yet notified

    if ((deadline.getTime() === today.getTime() || deadline.getTime() === tomorrow.getTime() || status !== "Completed") && notified !== "Notified") {

      message += `- ${taskName} (Due: ${Utilities.formatDate(deadline, "JST", "yyyy/MM/dd")})\n`;

      sheet.getRange(i + 1, 5).setValue("Notified"); // Update to Notified

      tasksFound = true;

    }

  }
  if (tasksFound) {

    const chatworkApiKey = "YOUR_CHATWORK_API_KEY"; // Replace with your actual API key

    const roomId = "YOUR_ROOM_ID"; // Replace with your actual chat room ID

    const url = `https://api.chatwork.com/v2/rooms/${roomId}/messages`;

    const options = {

      "method": "post",

      "headers": {

        "X-ChatWorkToken": chatworkApiKey

      },

      "payload": {

        "body": message

      }

    };

    UrlFetchApp.fetch(url, options);

    // Optional: Reset notified flags if needed, e.g., sheet.getRange(1, 5, sheet.getLastRow(), 1).setValue("Pending");

  }

}

  
Note: The code above is conceptual. You must replace placeholders like API key, room ID, sheet name, and column indices with your actual environment details. Also, consider implementing error handling and adjusting the logic for resetting notification flags as needed for your operation.
Conceptual GAS Code for Slack Notification
For Slack, you'll use the Incoming Webhooks URL.


function sendSlackNotification() {

  const ss = SpreadsheetApp.getActiveSpreadsheet();

  const sheet = ss.getSheetByName("TaskList"); // Specify your sheet name

  const data = sheet.getDataRange().getValues();

  const today = new Date();

  today.setHours(0, 0, 0, 0);
  const tomorrow = new Date(today);

  tomorrow.setDate(today.getDate() + 1);
  let taskDetails = [];
  for (let i = 1; i < data.length; i++) { // Skip header row

    const row = data[i];

    const taskName = row[0];

    const deadline = new Date(row[2]); // Due Date column

    const status = row[3]; // Status column

    const notified = row[4]; // Notification Flag column
    // Tasks due today or tomorrow, or not completed, and not yet notified

    if ((deadline.getTime() === today.getTime() || deadline.getTime() === tomorrow.getTime() || status !== "Completed") && notified !== "Notified") {

      taskDetails.push(`- *${taskName}* (Due: ${Utilities.formatDate(deadline, "JST", "yyyy/MM/dd")})`);

      sheet.getRange(i + 1, 5).setValue("Notified"); // Update to Notified

    }

  }
  if (taskDetails.length > 0) {

    const slackWebhookUrl = "YOUR_SLACK_WEBHOOK_URL"; // Replace with your actual Webhook URL

    const message = {

      "text": "【Tax Filing Reminder】\n" + taskDetails.join("\n")

    };

    const options = {

      "method": "post",

      "contentType": "application/json",

      "payload": JSON.stringify(message)

    };

    UrlFetchApp.fetch(slackWebhookUrl, options);

    // Optional: Reset notified flags if needed, e.g., sheet.getRange(1, 5, sheet.getLastRow(), 1).setValue("Pending");

  }

}

  
Note: Slack's Incoming Webhooks URL is sensitive information. It is strongly recommended to manage it securely, for example, by storing it in GAS script properties or environment variables, rather than hardcoding it directly into the script.
Step 4: Set Up Triggers
To make your GAS code run automatically every day, you need to set up a "Trigger". Click the clock icon (Triggers) on the left side of the script editor and select "Add Trigger". Choose the function you created (e.g., `sendChatworkNotification` or `sendSlackNotification`), set the "Time-driven" event source, choose "Day timer" for the type, and select the desired time of day (e.g., 9 AM) for execution. This ensures that notifications are sent automatically at the specified time each day.