TIN Lookup Integration Guide
Last updated February 27th, 2026
Overview
Our TIN Lookup service enables you to retrieve critical information associated with a Tax Identification Number (TIN). This guide will take you through the process of integrating this service into your application, allowing you to seamlessly access TIN-related details.
Prerequisites
To get started, you need to:
- Sign up on the Partner Dashboard and complete KYB.
- Create a
lookupapp and retrieve your Secret key. - Retrieve your Sandbox test credentials from the Sandbox page.
Integration Steps
Step 1: Make a TIN Lookup Request
To retrieve TIN-related information, send a POST request to the following endpoint:
Request
POST https://api.withmono.com/v3/lookup/tin
Request Body Parameters
number(required): Provide the Tax Identification Number (TIN) or the Corporate Affairs Commission (CAC) RC number for the lookup.channel(required): Specify the channel as "tin" or "cac".
Specifying Channels and Number
The TIN Lookup can be used to verify details of both individuals and businesses. For individuals, you can only pass tin in the channel field. However, for businesses, you can choose to pass either tin or cac in the channel field. When passing cac in the channel field, you must pass the RC number in the number field.
Include these two parameters in the request body to specify the TIN number and channel for the lookup.
Request Headers
Include the following header in your request for authentication:
mono-sec-key(required): Your Mono secret key.
cURL Sample Request
Request
curl -X POST \
-H "Content-Type: application/json" \
-H "mono-sec-key: YOUR_MONO_SECRET_KEY" \
-d '{
"number": "TIN_NUMBER", //RC_NUMBER
"channel": "tin" // cac
}' \
https://api.withmono.com/v3/lookup/tin
Step 2: Process the Response
The response for both individual and business TIN lookup requests are similar. What differentiates one from the other is the tin_type returned in the response, which can either be individual or corporate.
Individual TIN validation note
TINs in this flow can belong to individuals or corporates based on tin_type. For individual TIN validation (tin_type: individual), the upstream provider currently does not return taxpayer_name.
To complete matching on your end, use the returned email and phone_number fields to verify the customer against your existing records.
Sample response for BUSINESSES
If the TIN lookup request is successful for a business, you will receive the following response:
Request
{
"status": "successful",
"message": "Lookup Successful",
"timestamp": "2024-05-15T14:34:56.231Z",
"data": {
"taxpayer_name": "NOMO TECHNOLOGIES NIGERIA LIMITED",
"cac_reg_number": "RC0000015",
"firstin": "20000071-0001",
"jittin": "1000800004",
"nrs_tin": "2622431609295",
"tax_office": "LTO FINANCIAL SERVICES",
"phone_number": "08012345678",
"email": "hi@nomo.co",
"address": "PLOT 1230, AHMADU BELLO WAY, VICTORIA ISLAND, LAGOS, NIGERIA",
"tin_type": "CORPORATE"
}
}
Sample response for INDIVIDUALS
If the TIN lookup request for an individual is successful, you will receive the following response:
Request
{
"status": "successful",
"message": "Lookup Successful",
"timestamp": "2024-05-15T14:38:52.908Z",
"data": {
"taxpayer_name": null,
"cac_reg_number": "1060000000",
"firstin": "1060000000",
"jittin": "1060000000",
"nrs_tin": null,
"tax_office": "Lagos Internal Revenue Service",
"phone_number": "09087654321",
"email": "samuel@nomo.co",
"address": "9, Animashaun street, Lagos, Nigeria",
"tin_type": "INDIVIDUAL"
}
}
The response includes essential TIN-related information such as email, organization number, phone number, registration number, tax office, TIN type, and more.