Any business sending promotional Bulk SMS or voice calls in India has to check every number against TRAI's National Do Not Disturb (NDNC) Registry before sending — sending to a registered number risks fines and sender-ID blocking. "DND filter software" is the general term for the tools that do this check. This guide covers the three ways Indian businesses handle it, and what to look for before picking one.
It checks a phone number against the NDNC Registry's three categories — Fully Blocked (no promotional communication), Partially Blocked (blocks a subset of categories, e.g. banking or real estate), and Registered/Open — and returns whether that number can legally receive a promotional message. Transactional and service messages are not covered by DND and can go to any number.
Pull the NDNC data and maintain your own scrubbing logic. Gives full control but means owning data-freshness and TRAI compliance updates yourself — only worth it at very high volume.
A one-off tool or API you call before each campaign. Lower commitment than building in-house, but you're still responsible for wiring it into your sending workflow correctly every time.
DND filtering happens automatically on every campaign sent through the platform — no separate step to remember.
See the DND Filter service →
MetaReach's DND Filter runs automatically on every campaign sent through the platform, with API access if you'd rather check numbers from your own systems.
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