Messaging platform
SMS and one-time passcodes, on infrastructure you can audit.
One API for transactional SMS and OTP. Wallet billing to four decimal places, delivery reports, signed webhooks and a full audit trail.
Built for teams that ship
Every message is priced, queued, routed and logged.
One send endpoint
Bearer-authenticated REST call with validation, deduplication and Unicode detection.
OTP done properly
Codes are hashed at rest with configurable length, expiry, cooldown and attempt limits.
Wallet billing
Immutable ledger. Every debit, refund and top-up writes a transaction you can reconcile.
Provider agnostic
Routes pick a gateway by country, sender and message type, with fallback.
Signed webhooks
Delivery events are signed and retried with exponential backoff.
Compliance ready
DLT entity, header and template identifiers travel with every message.
Send your first message in a minute
cURL
curl -X POST https://api.blacksms.in/api/v1/sms/send \
-H "Authorization: Bearer $BLACKSMS_KEY" \
-H "Content-Type: application/json" \
-d '{"to":"919876543210","sender_id":"BLKSMS","message":"Your order has shipped"}'