How to Prevent Voice Calls from Being Marked as Spam

For MSG91 voice services, there are several best practices, safeguards, and system-level measures you can follow to reduce the risk of a number being marked as spam. While final spam labeling is controlled by telecom operators and user reports, these steps significantly lower the risk.

1. Call Content & Purpose

Use clear, purpose-driven voice calls (OTP, transactional, alerts).

Avoid vague or promotional language in transactional/OTP voice calls.

Always identify your brand clearly at the beginning of the call.

2. Call Frequency & Rate Control

Avoid high-frequency calls to the same number in a short time window.

Implement rate limiting (e.g., max OTP attempts per number per hour).

Add cool-down periods after failed OTP attempts.

Do not retry aggressively on unanswered or failed calls.

Excessive retries are one of the biggest reasons numbers get reported as spam.

3. User Consent & Opt-in

Make sure users have explicitly opted in to receive voice calls.

Trigger voice calls only after a user action (login, signup, password reset).

Avoid calling users who have not interacted recently.

Do not call to the user who are not registered with you, always target registered audience only.

4. Timing & Call Windows

Place calls only during reasonable hours.

Avoid early morning or late-night calls unless strictly required.

Respect Do Not Disturb (DND) categories numbers.

5. Number Management

Use dedicated caller IDs rather than rotating random numbers.

Avoid frequently changing caller numbers.

6. Call Quality & Experience

Ensure good audio quality

Keep messages short and to the point.

Avoid long IVRs or unnecessary prompts.

Clearly inform users how to stop or ignore future calls if applicable.

7. Monitoring & Alerts

Monitor:

Call failure rates

Drop rates

Repeated retries

User complaints

Set alerts for sudden spikes in voice traffic.

Note: Even with all safeguards, spam tagging is ultimately controlled by telecom operators and end-user reports. No provider (including MSG91) can guarantee 100% protection. However, following these practices greatly minimizes the risk.

MSG91 do not offer Promotional Voice Call services.

Block Caller in case of escalation to avoid calling the same client.