NI & identifiers
Add or update an NI category for an employee
POST
/
employees
/
{employeeId}
/
ni-category
Add or update an NI category for an employee
curl --request POST \
--url https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category \
--header 'Content-Type: application/json' \
--header 'X-Auth-Token: <api-key>' \
--header 'X-Org-Id: <api-key>' \
--data '
{
"category": "A",
"effectiveDate": "2025-04-06",
"reason": "HMRC Update",
"issuedBy": "HMRC"
}
'import requests
url = "https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category"
payload = {
"category": "A",
"effectiveDate": "2025-04-06",
"reason": "HMRC Update",
"issuedBy": "HMRC"
}
headers = {
"X-Auth-Token": "<api-key>",
"X-Org-Id": "<api-key>",
"Content-Type": "application/json"
}
response = requests.post(url, json=payload, headers=headers)
print(response.text)const options = {
method: 'POST',
headers: {
'X-Auth-Token': '<api-key>',
'X-Org-Id': '<api-key>',
'Content-Type': 'application/json'
},
body: JSON.stringify({
category: 'A',
effectiveDate: '2025-04-06',
reason: 'HMRC Update',
issuedBy: 'HMRC'
})
};
fetch('https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category', options)
.then(res => res.json())
.then(res => console.log(res))
.catch(err => console.error(err));<?php
$curl = curl_init();
curl_setopt_array($curl, [
CURLOPT_URL => "https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "POST",
CURLOPT_POSTFIELDS => json_encode([
'category' => 'A',
'effectiveDate' => '2025-04-06',
'reason' => 'HMRC Update',
'issuedBy' => 'HMRC'
]),
CURLOPT_HTTPHEADER => [
"Content-Type: application/json",
"X-Auth-Token: <api-key>",
"X-Org-Id: <api-key>"
],
]);
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if ($err) {
echo "cURL Error #:" . $err;
} else {
echo $response;
}package main
import (
"fmt"
"strings"
"net/http"
"io"
)
func main() {
url := "https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category"
payload := strings.NewReader("{\n \"category\": \"A\",\n \"effectiveDate\": \"2025-04-06\",\n \"reason\": \"HMRC Update\",\n \"issuedBy\": \"HMRC\"\n}")
req, _ := http.NewRequest("POST", url, payload)
req.Header.Add("X-Auth-Token", "<api-key>")
req.Header.Add("X-Org-Id", "<api-key>")
req.Header.Add("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))
}HttpResponse<String> response = Unirest.post("https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category")
.header("X-Auth-Token", "<api-key>")
.header("X-Org-Id", "<api-key>")
.header("Content-Type", "application/json")
.body("{\n \"category\": \"A\",\n \"effectiveDate\": \"2025-04-06\",\n \"reason\": \"HMRC Update\",\n \"issuedBy\": \"HMRC\"\n}")
.asString();require 'uri'
require 'net/http'
url = URI("https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Post.new(url)
request["X-Auth-Token"] = '<api-key>'
request["X-Org-Id"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n \"category\": \"A\",\n \"effectiveDate\": \"2025-04-06\",\n \"reason\": \"HMRC Update\",\n \"issuedBy\": \"HMRC\"\n}"
response = http.request(request)
puts response.read_body{
"message": {
"text": "<string>",
"token": "<string>",
"tokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
},
"content": {
"data": {
"name": {
"firstName": "John",
"lastName": "Smith",
"middleName": "Edward",
"title": "Mr"
},
"email": "john.smith@company.com",
"birthGender": "Male",
"birthDate": "1985-07-23",
"hoursWorkedCategory": "Above30Hours",
"id": "emp_12345",
"payrollConfigId": "payroll_config_001",
"starterDetails": {
"startDate": "2024-01-15",
"starterDeclaration": "ThisIsMyOnlyJob",
"alreadySentToHmrcFps": false,
"secondedDetails": {
"eEACitizen": true,
"ePM6": false,
"stayStatus": "Stay183DaysOrMore"
}
},
"taxCodesPerYear": {
"2025": [
{
"code": "1257L",
"effectiveDate": "2025-04-06",
"reason": "HMRC Update",
"issuedBy": "HMRC",
"week1Month1": false
}
]
},
"niDetails": {
"categoriesPerYear": {},
"nationalInsuranceNumber": "QQ123456C"
},
"phone": "+447700900123",
"maritalStatus": "Married",
"salary": 35000,
"employeeCode": "EMP001",
"secondaryEmail": "john.secondary@company.com",
"address": {
"line1": "123 Main Street",
"line2": "Apt 4B",
"city": "London",
"county": "Greater London",
"postcode": "SW1A 1AA",
"countryCode": "GB"
},
"bankAccounts": [
{
"accountNumber": "12345678",
"sortCode": "123456",
"allocationPercentage": 100,
"isPrimaryPayrollAccount": true,
"accountHolderName": "John Smith"
}
],
"studentDetails": {
"studentLoanDetails": {
"loanType": "Plan2",
"startDate": "2010-09-01",
"endDate": "2025-07-31"
},
"postgraduateLoanDetails": {
"loanType": "PostgraduateLoan",
"startDate": "2015-09-01",
"endDate": "2028-07-31"
}
},
"tags": [
{
"name": "FullTime",
"group": "EmploymentType",
"value": "FullTime"
}
],
"previousEmployment": {
"2026": {
"grossTaxable": 15000,
"tax": 3000
}
},
"gender": "Male",
"secondaryPhone": "+447700900124",
"passportNumber": "123456789",
"previousNames": [
"John Doe"
],
"directorDetails": {
"directorsNICType": "Annual",
"appointmentDate": "2024-01-15",
"endDate": "2025-03-31"
},
"isIrregularEmployment": false,
"isOffPayrollWorker": false,
"workplaceDetails": {
"workplaceId": "workplace_001",
"workplaceName": "Head Office",
"address": {
"line1": "123 Main Street",
"line2": "Apt 4B",
"city": "London",
"county": "Greater London",
"postcode": "SW1A 1AA",
"countryCode": "GB"
}
},
"workingDays": {
"standardWorkingDays": {
"monday": true,
"tuesday": true,
"wednesday": true,
"thursday": true,
"friday": true,
"saturday": false,
"sunday": false
},
"shiftPattern": {
"rotationStartDate": "2024-01-01",
"shifts": [
{
"name": "Morning Shift",
"workingDays": {
"monday": true,
"tuesday": true,
"wednesday": true,
"thursday": true,
"friday": true,
"saturday": false,
"sunday": false
},
"durationInDays": 5,
"weekNumber": 1
},
{
"name": "Night Shift",
"workingDays": {
"monday": true,
"tuesday": true,
"wednesday": true,
"thursday": true,
"friday": true,
"saturday": false,
"sunday": false
},
"durationInDays": 5,
"weekNumber": 2
}
],
"patternType": "FourOnFourOff",
"patternWeeks": 8
},
"workingPattern": "Standard",
"explicitSchedule": {
"weeks": [
{
"weekCommencing": "2026-07-06",
"workingDays": {
"monday": true,
"tuesday": true,
"wednesday": true,
"thursday": true,
"friday": true,
"saturday": false,
"sunday": false
}
}
]
}
},
"partnerDetails": {
"name": {
"firstName": "John",
"lastName": "Smith",
"middleName": "Edward",
"title": "Mr"
},
"nationalInsuranceNumber": "QQ654321A"
},
"department": "Engineering",
"jobTitle": "Software Engineer",
"leaverDetails": {
"leavingDate": "2024-12-31",
"reason": "Retirement",
"issuedBy": "Employer",
"reportedToHmrc": false,
"finalisedOnPayslip": false
},
"earningsToDatePerYear": {},
"openingBalance": {},
"openingBalanceDirector": {},
"directorEarningsToDatePerYear": {},
"payrollId": "PAY123",
"createdDate": "2023-01-15T10:00:00Z",
"createdBy": "admin@company.com",
"updatedDate": "2023-06-01T12:00:00Z",
"updatedBy": "hr@company.com"
},
"metadata": {
"dateFormat": "yyyy-MM-dd",
"dateTimeFormat": "yyyy-MM-ddTHH:mm:ss.fffZ",
"paginationToken": "<string>"
}
},
"validationIssues": [
{
"field": "<string>",
"reason": "<string>",
"reasonToken": "<string>",
"reasonTokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
}
],
"messageToken": "<string>"
}{
"message": {
"text": "<string>",
"token": "<string>",
"tokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
},
"content": {
"data": {},
"metadata": {
"dateFormat": "yyyy-MM-dd",
"dateTimeFormat": "yyyy-MM-ddTHH:mm:ss.fffZ",
"paginationToken": "<string>"
}
},
"validationIssues": [
{
"field": "<string>",
"reason": "<string>",
"reasonToken": "<string>",
"reasonTokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
}
],
"messageToken": "<string>"
}{
"message": {
"text": "<string>",
"token": "<string>",
"tokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
},
"content": {
"data": {},
"metadata": {
"dateFormat": "yyyy-MM-dd",
"dateTimeFormat": "yyyy-MM-ddTHH:mm:ss.fffZ",
"paginationToken": "<string>"
}
},
"validationIssues": [
{
"field": "<string>",
"reason": "<string>",
"reasonToken": "<string>",
"reasonTokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
}
],
"messageToken": "<string>"
}{
"message": {
"text": "<string>",
"token": "<string>",
"tokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
},
"content": {
"data": {},
"metadata": {
"dateFormat": "yyyy-MM-dd",
"dateTimeFormat": "yyyy-MM-ddTHH:mm:ss.fffZ",
"paginationToken": "<string>"
}
},
"validationIssues": [
{
"field": "<string>",
"reason": "<string>",
"reasonToken": "<string>",
"reasonTokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
}
],
"messageToken": "<string>"
}Authorizations
Access token obtained from OAuth2 client credentials flow
Organisation to scope the request to. Required when the principal can access more than one organisation; optional for single-organisation principals (the authorizer resolves it automatically).
Path Parameters
The ID of the employee
Body
application/json
HMRC-published NI category letter for payroll submissions.
Available options:
A, B, C, D, E, F, H, I, J, K, L, M, N, S, V, X, Z Example:
"A"
Date when this category becomes effective
Example:
"2025-04-06"
Reason for the category
Example:
"HMRC Update"
Who issued the category. Valid values: 'HMRC', 'Employer'
Example:
"HMRC"
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⌘I
Add or update an NI category for an employee
curl --request POST \
--url https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category \
--header 'Content-Type: application/json' \
--header 'X-Auth-Token: <api-key>' \
--header 'X-Org-Id: <api-key>' \
--data '
{
"category": "A",
"effectiveDate": "2025-04-06",
"reason": "HMRC Update",
"issuedBy": "HMRC"
}
'import requests
url = "https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category"
payload = {
"category": "A",
"effectiveDate": "2025-04-06",
"reason": "HMRC Update",
"issuedBy": "HMRC"
}
headers = {
"X-Auth-Token": "<api-key>",
"X-Org-Id": "<api-key>",
"Content-Type": "application/json"
}
response = requests.post(url, json=payload, headers=headers)
print(response.text)const options = {
method: 'POST',
headers: {
'X-Auth-Token': '<api-key>',
'X-Org-Id': '<api-key>',
'Content-Type': 'application/json'
},
body: JSON.stringify({
category: 'A',
effectiveDate: '2025-04-06',
reason: 'HMRC Update',
issuedBy: 'HMRC'
})
};
fetch('https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category', options)
.then(res => res.json())
.then(res => console.log(res))
.catch(err => console.error(err));<?php
$curl = curl_init();
curl_setopt_array($curl, [
CURLOPT_URL => "https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "POST",
CURLOPT_POSTFIELDS => json_encode([
'category' => 'A',
'effectiveDate' => '2025-04-06',
'reason' => 'HMRC Update',
'issuedBy' => 'HMRC'
]),
CURLOPT_HTTPHEADER => [
"Content-Type: application/json",
"X-Auth-Token: <api-key>",
"X-Org-Id: <api-key>"
],
]);
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if ($err) {
echo "cURL Error #:" . $err;
} else {
echo $response;
}package main
import (
"fmt"
"strings"
"net/http"
"io"
)
func main() {
url := "https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category"
payload := strings.NewReader("{\n \"category\": \"A\",\n \"effectiveDate\": \"2025-04-06\",\n \"reason\": \"HMRC Update\",\n \"issuedBy\": \"HMRC\"\n}")
req, _ := http.NewRequest("POST", url, payload)
req.Header.Add("X-Auth-Token", "<api-key>")
req.Header.Add("X-Org-Id", "<api-key>")
req.Header.Add("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))
}HttpResponse<String> response = Unirest.post("https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category")
.header("X-Auth-Token", "<api-key>")
.header("X-Org-Id", "<api-key>")
.header("Content-Type", "application/json")
.body("{\n \"category\": \"A\",\n \"effectiveDate\": \"2025-04-06\",\n \"reason\": \"HMRC Update\",\n \"issuedBy\": \"HMRC\"\n}")
.asString();require 'uri'
require 'net/http'
url = URI("https://api.sandbox.flowpayroll.ai/v1/employees/{employeeId}/ni-category")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Post.new(url)
request["X-Auth-Token"] = '<api-key>'
request["X-Org-Id"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n \"category\": \"A\",\n \"effectiveDate\": \"2025-04-06\",\n \"reason\": \"HMRC Update\",\n \"issuedBy\": \"HMRC\"\n}"
response = http.request(request)
puts response.read_body{
"message": {
"text": "<string>",
"token": "<string>",
"tokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
},
"content": {
"data": {
"name": {
"firstName": "John",
"lastName": "Smith",
"middleName": "Edward",
"title": "Mr"
},
"email": "john.smith@company.com",
"birthGender": "Male",
"birthDate": "1985-07-23",
"hoursWorkedCategory": "Above30Hours",
"id": "emp_12345",
"payrollConfigId": "payroll_config_001",
"starterDetails": {
"startDate": "2024-01-15",
"starterDeclaration": "ThisIsMyOnlyJob",
"alreadySentToHmrcFps": false,
"secondedDetails": {
"eEACitizen": true,
"ePM6": false,
"stayStatus": "Stay183DaysOrMore"
}
},
"taxCodesPerYear": {
"2025": [
{
"code": "1257L",
"effectiveDate": "2025-04-06",
"reason": "HMRC Update",
"issuedBy": "HMRC",
"week1Month1": false
}
]
},
"niDetails": {
"categoriesPerYear": {},
"nationalInsuranceNumber": "QQ123456C"
},
"phone": "+447700900123",
"maritalStatus": "Married",
"salary": 35000,
"employeeCode": "EMP001",
"secondaryEmail": "john.secondary@company.com",
"address": {
"line1": "123 Main Street",
"line2": "Apt 4B",
"city": "London",
"county": "Greater London",
"postcode": "SW1A 1AA",
"countryCode": "GB"
},
"bankAccounts": [
{
"accountNumber": "12345678",
"sortCode": "123456",
"allocationPercentage": 100,
"isPrimaryPayrollAccount": true,
"accountHolderName": "John Smith"
}
],
"studentDetails": {
"studentLoanDetails": {
"loanType": "Plan2",
"startDate": "2010-09-01",
"endDate": "2025-07-31"
},
"postgraduateLoanDetails": {
"loanType": "PostgraduateLoan",
"startDate": "2015-09-01",
"endDate": "2028-07-31"
}
},
"tags": [
{
"name": "FullTime",
"group": "EmploymentType",
"value": "FullTime"
}
],
"previousEmployment": {
"2026": {
"grossTaxable": 15000,
"tax": 3000
}
},
"gender": "Male",
"secondaryPhone": "+447700900124",
"passportNumber": "123456789",
"previousNames": [
"John Doe"
],
"directorDetails": {
"directorsNICType": "Annual",
"appointmentDate": "2024-01-15",
"endDate": "2025-03-31"
},
"isIrregularEmployment": false,
"isOffPayrollWorker": false,
"workplaceDetails": {
"workplaceId": "workplace_001",
"workplaceName": "Head Office",
"address": {
"line1": "123 Main Street",
"line2": "Apt 4B",
"city": "London",
"county": "Greater London",
"postcode": "SW1A 1AA",
"countryCode": "GB"
}
},
"workingDays": {
"standardWorkingDays": {
"monday": true,
"tuesday": true,
"wednesday": true,
"thursday": true,
"friday": true,
"saturday": false,
"sunday": false
},
"shiftPattern": {
"rotationStartDate": "2024-01-01",
"shifts": [
{
"name": "Morning Shift",
"workingDays": {
"monday": true,
"tuesday": true,
"wednesday": true,
"thursday": true,
"friday": true,
"saturday": false,
"sunday": false
},
"durationInDays": 5,
"weekNumber": 1
},
{
"name": "Night Shift",
"workingDays": {
"monday": true,
"tuesday": true,
"wednesday": true,
"thursday": true,
"friday": true,
"saturday": false,
"sunday": false
},
"durationInDays": 5,
"weekNumber": 2
}
],
"patternType": "FourOnFourOff",
"patternWeeks": 8
},
"workingPattern": "Standard",
"explicitSchedule": {
"weeks": [
{
"weekCommencing": "2026-07-06",
"workingDays": {
"monday": true,
"tuesday": true,
"wednesday": true,
"thursday": true,
"friday": true,
"saturday": false,
"sunday": false
}
}
]
}
},
"partnerDetails": {
"name": {
"firstName": "John",
"lastName": "Smith",
"middleName": "Edward",
"title": "Mr"
},
"nationalInsuranceNumber": "QQ654321A"
},
"department": "Engineering",
"jobTitle": "Software Engineer",
"leaverDetails": {
"leavingDate": "2024-12-31",
"reason": "Retirement",
"issuedBy": "Employer",
"reportedToHmrc": false,
"finalisedOnPayslip": false
},
"earningsToDatePerYear": {},
"openingBalance": {},
"openingBalanceDirector": {},
"directorEarningsToDatePerYear": {},
"payrollId": "PAY123",
"createdDate": "2023-01-15T10:00:00Z",
"createdBy": "admin@company.com",
"updatedDate": "2023-06-01T12:00:00Z",
"updatedBy": "hr@company.com"
},
"metadata": {
"dateFormat": "yyyy-MM-dd",
"dateTimeFormat": "yyyy-MM-ddTHH:mm:ss.fffZ",
"paginationToken": "<string>"
}
},
"validationIssues": [
{
"field": "<string>",
"reason": "<string>",
"reasonToken": "<string>",
"reasonTokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
}
],
"messageToken": "<string>"
}{
"message": {
"text": "<string>",
"token": "<string>",
"tokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
},
"content": {
"data": {},
"metadata": {
"dateFormat": "yyyy-MM-dd",
"dateTimeFormat": "yyyy-MM-ddTHH:mm:ss.fffZ",
"paginationToken": "<string>"
}
},
"validationIssues": [
{
"field": "<string>",
"reason": "<string>",
"reasonToken": "<string>",
"reasonTokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
}
],
"messageToken": "<string>"
}{
"message": {
"text": "<string>",
"token": "<string>",
"tokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
},
"content": {
"data": {},
"metadata": {
"dateFormat": "yyyy-MM-dd",
"dateTimeFormat": "yyyy-MM-ddTHH:mm:ss.fffZ",
"paginationToken": "<string>"
}
},
"validationIssues": [
{
"field": "<string>",
"reason": "<string>",
"reasonToken": "<string>",
"reasonTokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
}
],
"messageToken": "<string>"
}{
"message": {
"text": "<string>",
"token": "<string>",
"tokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
},
"content": {
"data": {},
"metadata": {
"dateFormat": "yyyy-MM-dd",
"dateTimeFormat": "yyyy-MM-ddTHH:mm:ss.fffZ",
"paginationToken": "<string>"
}
},
"validationIssues": [
{
"field": "<string>",
"reason": "<string>",
"reasonToken": "<string>",
"reasonTokenArguments": [
{
"name": "<string>",
"value": "<string>"
}
]
}
],
"messageToken": "<string>"
}