Restflow.io

## Introduction

Tracking and logging user activity in a SaaS environment is critical for usage-based billing, analytics, and customer insights. Startups and data & analytics teams often struggle with manual or inconsistent methods of capturing usage data per subscription plan, leading to billing inaccuracies or delayed reports.

This guide walks you through building a robust, automated workflow using n8n to log user activity and usage metrics per plan in your SaaS application. The workflow integrates commonly used tools and services and provides an adaptable architecture to scale with your product.

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## What Problem Does This Solve?

SaaS businesses operating with tiered subscription plans or usage-based billing need accurate logging of each user’s activity based on their subscribed plan. Manual tracking or ad-hoc logging leads to:

– Billing errors and customer disputes
– Delays in usage data reporting
– Difficulty in identifying usage patterns per plan

This automation addresses these by automatically:

– Capturing usage data from your app or APIs
– Validating user subscription plans
– Logging usage to a central system (e.g., Google Sheets, database, or analytics platforms)
– Triggering alerts or downstream processes based on thresholds

**Beneficiaries:** Product managers, Data & Analytics teams, Finance teams, and Customer Success teams.

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## Tools and Services Integrated

– **n8n:** Open-source workflow automation platform
– **Your SaaS’s API or webhook endpoint:** Source of user usage events
– **Database (PostgreSQL/MySQL) or Google Sheets:** Storage for logged usage
– **Slack (optional):** For real-time alerts
– **Email/SMS (optional):** For usage threshold notifications

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## Workflow Overview

1. **Trigger:** Capture usage events via webhook or API polling.
2. **Plan validation:** Fetch and confirm user subscription plan.
3. **Transform/Enrich data:** Format usage data and correlate with plan details.
4. **Log usage:** Insert or update records in database or Google Sheets.
5. **Threshold check (optional):** If usage exceeds limits, notify via Slack or email.

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## Step-by-Step Tutorial

### Prerequisites

– n8n instance set up (cloud or self-hosted)
– Access to your SaaS API or an event webhook
– Access to a database or Google Sheets to store usage logs
– Slack workspace or email account for alerts (optional)

### Step 1: Capture Usage Events

1. **Webhook node:**
– In n8n, create a new workflow.
– Add a **Webhook** node to listen for usage events from your SaaS.
– Configure the webhook URL and method (usually POST).
– Your SaaS app should send usage events including user ID, timestamp, and activity metrics.

2. **Test:** Trigger a usage event to ensure n8n receives the payload.

### Step 2: Fetch User Subscription Plan

1. **HTTP Request node:**
– Use the user ID from the webhook data to call your SaaS user management API.
– Retrieve the user’s current subscription plan (e.g., free, pro, enterprise).
– Ensure to handle API authentication (API keys, tokens).

2. **Error Handling:**
– Add a **NoOp** or error workflow branch if fetching plan details fails.

### Step 3: Format and Enrich Usage Data

1. **Function node:**
– Combine webhook event data and subscription plan info.
– Format data into a structured JSON object with: user ID, plan, usage metric, timestamp.

2. **Add calculated fields:**
– E.g., calculate usage cost based on plan rates.

### Step 4: Log Usage Data

Two common options:

– **Google Sheets:**
– Add a **Google Sheets** node.
– Authenticate Google API.
– Append the formatted usage record as a new row.

– **Database:**
– Add **PostgreSQL** or **MySQL** node.
– Insert a new row or update existing usage summary.

Include timestamp and all relevant fields for auditability.

### Step 5: Usage Threshold Alerts (Optional)

1. **IF node:**
– Check if usage exceeds defined plan limits.

2. **Slack node:**
– Send alert messages to your team channel.

3. **Email node:**
– Optionally send automated emails to customers upon threshold breaches.

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## Common Errors and Tips

– **API authentication failures:** Ensure your tokens or keys are valid and not expired.
– **Data discrepancies:** Validate that usage units sent match what the plan expects (e.g., minutes, API calls).
– **Webhook retries:** Implement idempotency keys or deduplication for webhook retries.
– **Rate Limits:** Monitor and throttle API calls to prevent service bans.
– **Error handling:** Use n8n’s error workflow to catch and log failed steps.

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## Scaling and Adaptation

– **Multi-environment setups:** Use environment variables in n8n to switch between staging and production APIs.
– **Different usage types:** Extend the Function node logic to handle multiple event types (e.g., login, data processed).
– **Storage migration:** Switch from Google Sheets to a database as usage volume grows.
– **Real-time BI integration:** Instead of logs, push usage data directly to analytics tools like Google BigQuery or Snowflake.
– **Notification customization:** Add more complex alert rules or integrate with PagerDuty.

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## Summary and Bonus Tips

Automating usage logging per plan with n8n creates a reliable, scalable layer critical for billing accuracy and analytics. This workflow captures usage data, validates plans, logs activities, and alerts teams efficiently.

**Bonus Tip:** Implement incremental daily usage aggregation within n8n by adding scheduled workflows that summarize usage data per user per day. This reduces storage volume and speeds up reporting.

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By following this detailed tutorial, your Data & Analytics department can build a transparent and automated usage tracking system that supports business growth and operational efficiency.