Privacy Policy

Effective 28 August 2026. LinguaMatrix by NANDAX is designed to keep learning activity local-first while using a small server account layer for secure paid access.

Information we store on the server

For an account we store your email address, a one-way password hash, plan and subscription status, one-time Preview usage/timing, billing gateway, provider subscription identifier and operational timestamps. We do not store your card, UPI PIN, bank-account credentials or full payment instrument details.

Payments

Recurring payments are processed by Razorpay and/or Cashfree. Their checkout pages and systems handle payment and mandate information under their own privacy terms. LinguaMatrix receives only the identifiers and status information needed to verify and maintain your Free or Premium entitlement.

Learning data on your device

Saved expressions, My Learning progress, review evidence, practice history and preferences are primarily stored in your browser using local storage or IndexedDB. Clearing browser/site data can remove this local learning history unless a future sync feature explicitly says otherwise.

Speech features

Text-to-speech uses voices exposed by your device or browser. Speech recognition, where available, is provided by the browser/platform and may use that platform's online speech services. LinguaMatrix does not claim that transcript matching is a phoneme-level accent score.

Optional AI

AI refinement is optional and Premium-gated. When enabled, the text you submit and compact context needed for the request may be sent through a protected server endpoint to the configured AI provider. Provider API secrets are never intentionally placed in the public PWA.

Security and operational data

We use server sessions, rate limiting and signed payment webhooks. Rate-limit keys are derived from request information to reduce abuse. Billing event identifiers are retained for reconciliation and duplicate-event protection.

Retention and choices

Account and subscription records are retained while needed to provide the service, meet billing/reconciliation needs and comply with applicable requirements. You may cancel recurring billing from your account. For account or privacy requests, contact __SUPPORT_EMAIL__.

Changes

If our data practices materially change, this policy will be updated on this page.