Initiate Phone Number NIN Lookup
Last updated August 3rd, 2026
post api.withmono.com/v3/lookup/phone/initiateThis resource is used to initiate a phone number lookup. An OTP is sent to the phone number which is to be used with the Verify OTP endpoint.
⚠️ Billing Notice: Phone Number NIN Lookup
All Phone Number NIN Lookup API requests are billable, including failed lookups (e.g. phone number not linked to a NIN). Authentication failures before the provider call, internal server failures, and provider downtime failures are non-billable.
To avoid unnecessary charges:
Validate phone numbers before calling the API (must be 11-14 digits, optionally prefixed with
+).Avoid bulk or blind verification of unverified phone numbers.
Implement throttling and monitor failed request rates.
If you need Phone Number NIN Lookup temporarily disabled to prevent charges, contact your account manager or email support@mono.co
Sandbox Credentials
Kindly retrieve your Sandbox test credentials from the Sandbox page here.
Request
curl --request POST \
--url https://api.withmono.com/v3/lookup/phone/initiate \
--header 'accept: application/json' \
--header 'content-type: application/json' \
--header 'mono-sec-key: string' \
--data '{"phone_number":"string"}'
Response
Choose an option from the drop down or click one of these buttons to see an example:
