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Terms of Service

Last updated: November 2025

Introduction

Welcome to Substash, a subscription tracking browser extension for Chrome, Firefox, Brave, Edge, Opera, Vivaldi, and other Chromium-based browsers. These Terms of Service ("Terms") govern your use of our service and explain your rights and responsibilities.

By using Substash, you agree to these Terms. If you do not agree to these Terms, please do not use our service.

Age requirement

Substash is intended for users aged 18 and older. If you are under 18, you must obtain parental consent before using our service. By using Substash, you confirm that you meet this age requirement or have obtained appropriate parental consent.

Service description

Substash helps you track your subscriptions and manage billing cycles. Our free service includes:

  • Subscription tracking with billing cycle management
  • Automated email alerts for upcoming renewals and trial expirations
  • Multi-currency support with real-time exchange rates (30+ currencies)
  • Cross-device synchronization via cloud database
  • Insights and analytics on your subscription spending
  • Offline-first functionality with automatic online sync

Substash is 100% free with no paid plans, premium tiers, in-app purchases, or advertisements.

Data collection overview

Substash is designed with privacy in mind. We collect minimal data necessary to provide our subscription tracking service:

  • Email address for secure passwordless OTP authentication
  • Subscription data you choose to track (names, costs, billing cycles, renewal dates, notes)
  • Email alert preferences (notification timing for renewals and trials)
  • Anonymous pageview analytics (via PostHog, no user identification)
  • Campaign tracking parameters (UTM links in emails, GDPR-compliant)

We do not access your browsing history, personal files, or any sensitive financial information beyond what you explicitly choose to track. Authentication requires only your email address for secure one-time password delivery (6-digit codes, 5-minute expiry).

Third-party integrations

Substash uses trusted third-party services to provide our functionality:

  • Supabase: Backend infrastructure for authentication, PostgreSQL database storage, and serverless Edge Functions
  • Amazon SES: Email delivery service for OTP codes, welcome messages, and subscription alerts
  • Frankfurter API: Currency conversion service (no personal data shared, only currency codes)
  • PostHog: Product analytics platform (EU region, anonymous pageviews only, no user identification)
  • DuckDuckGo: Public icon API for fetching subscription logos

We only request the minimum browser permissions necessary (storage, host permissions for Supabase and Frankfurter API) and do not share your data beyond these essential service providers. See our Privacy Policy for detailed information on data sharing.

User rights and responsibilities

Your rights:

  • Access your subscription data through the extension UI at any time
  • Update or modify subscription information whenever you choose
  • Delete individual subscriptions or your entire account with immediate cascade deletion
  • Control email alert preferences or disable alerts entirely
  • Request support and provide feedback

Your responsibilities:

  • Use the service for personal or work subscription tracking in a lawful manner
  • Provide accurate information when tracking subscriptions
  • Keep your account secure by protecting access to your email
  • Not attempt to reverse engineer, modify, or compromise the service
  • Not use the service for automated scraping or abuse
  • Report any bugs or security issues you discover

Service availability and disclaimers

Substash is provided free of charge as-is. We aim for high availability but cannot guarantee 100% uptime. Service availability depends on third-party infrastructure providers (Supabase, Amazon SES).

We'll provide notice of any planned maintenance or significant changes to the service through the extension or our website.

Disclaimer of warranties:

Substash is provided "as is" without warranties of any kind, either express or implied, including but not limited to warranties of merchantability, fitness for a particular purpose, or non-infringement. We do not guarantee that the service will be uninterrupted, error-free, or secure.

Limitation of liability:

To the maximum extent permitted by law, Substash and its operators shall not be liable for any indirect, incidental, special, consequential, or punitive damages, or any loss of profits or revenues, whether incurred directly or indirectly, or any loss of data, use, goodwill, or other intangible losses resulting from your use of the service. We are not responsible for missed subscription payments, billing errors, or financial loss resulting from reliance on the service.

Termination

You may terminate your use of Substash at any time by deleting your account through the extension settings. Upon termination, all your subscriptions and email alerts will be immediately and permanently deleted from our database through cascade deletion.

We reserve the right to suspend or terminate access to the service for violations of these Terms, abusive behavior, or attempts to compromise the service security.

Intellectual property

Substash and its original content, features, functionality, design, and branding are owned by Chris Lim and are protected by international copyright, trademark, and other intellectual property laws.

You retain all rights to the subscription data you enter into Substash. By using the service, you grant us a limited license to store and process your data solely for the purpose of providing the service to you.

Changes to these terms

We may update these Terms from time to time. We'll notify users of any significant changes through the extension or our website. Continued use of the service after changes constitutes acceptance of the updated Terms.

The "Last updated" date at the top of this page indicates when these Terms were last revised.

Governing law

These Terms shall be governed by and construed in accordance with applicable laws. Any disputes arising from these Terms or your use of Substash shall be resolved in accordance with the laws of the jurisdiction where the service operator is located.

Contact us

If you have questions about these Terms of Service, please email Email us.