SMS sender IDs & compliance

Every country regulates SMS sender names ("Sender IDs") differently: some allow any alphanumeric name, some require pre-registration, some force a numeric sender. Getting this wrong means silently dropped messages — you pay, nothing arrives.

WeZend encodes these rules into the platform so you cannot make that mistake.

Register your sender names

Add the names you send as (e.g. Acme, max 11 characters alphanumeric) under Settings → Senders or via POST /v1/senders. Where a destination country requires registration (e.g. several telco markets), the request is routed to the operator process and you can follow its approval status in the dashboard.

Check the rules programmatically

curl "https://api.wezend.com/v1/sender/rules?country=DK" -H "X-API-Key: $WEZEND_API_KEY"

Returns what the destination allows: alphanumeric yes/no, registration required, max length, and fallback behaviour.

Validate before sending

curl -X POST https://api.wezend.com/v1/sender/validate \
  -H "X-API-Key: $WEZEND_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "sender": "Acme", "to": "+4670123456" }'

The response tells you whether the send would be compliant and, if not, what the platform would substitute (for example a registered numeric sender). The same check runs automatically inside /v1/messages/send — validation is a pre-flight convenience so your UI can warn users early.

Marketing traffic

Marketing SMS additionally respects consent, quiet hours and frequency caps — transactional traffic (OTPs, receipts) is exempt by design.