Tax ID Validator API
Tax ID Validator is a comprehensive tool for validating US Tax IDs including Social Security Numbers (SSN), Employer Identification Numbers (EIN), and Individual Taxpayer Identification Numbers (ITIN).
The Tax ID Validator API provides reliable and fast access to tax id validator data through a simple REST interface. Built for developers who need consistent, high-quality results with minimal setup time.
To use Tax ID Validator, you need an API key. You can get one by creating a free account and visiting your dashboard.
GET Endpoint
https://api.apiverve.com/v1/taxidvalidatorCode Examples
Here are examples of how to call the Tax ID Validator API in different programming languages:
curl -X GET \
"https://api.apiverve.com/v1/taxidvalidator?taxid=123-45-6789" \
-H "X-API-Key: your_api_key_here"const response = await fetch('https://api.apiverve.com/v1/taxidvalidator?taxid=123-45-6789', {
method: 'GET',
headers: {
'X-API-Key': 'your_api_key_here',
'Content-Type': 'application/json'
}
});
const data = await response.json();
console.log(data);import requests
headers = {
'X-API-Key': 'your_api_key_here',
'Content-Type': 'application/json'
}
response = requests.get('https://api.apiverve.com/v1/taxidvalidator?taxid=123-45-6789', headers=headers)
data = response.json()
print(data)const https = require('https');
const url = require('url');
const options = {
method: 'GET',
headers: {
'X-API-Key': 'your_api_key_here',
'Content-Type': 'application/json'
}
};
const req = https.request('https://api.apiverve.com/v1/taxidvalidator?taxid=123-45-6789', options, (res) => {
let data = '';
res.on('data', (chunk) => data += chunk);
res.on('end', () => console.log(JSON.parse(data)));
});
req.end();<?php
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://api.apiverve.com/v1/taxidvalidator?taxid=123-45-6789');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');
curl_setopt($ch, CURLOPT_HTTPHEADER, [
'X-API-Key: your_api_key_here',
'Content-Type: application/json'
]);
$response = curl_exec($ch);
curl_close($ch);
$data = json_decode($response, true);
print_r($data);
?>package main
import (
"fmt"
"io"
"net/http"
)
func main() {
req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/taxidvalidator?taxid=123-45-6789", nil)
req.Header.Set("X-API-Key", "your_api_key_here")
req.Header.Set("Content-Type", "application/json")
client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
panic(err)
}
defer resp.Body.Close()
body, _ := io.ReadAll(resp.Body)
fmt.Println(string(body))
}require 'net/http'
require 'json'
uri = URI('https://api.apiverve.com/v1/taxidvalidator?taxid=123-45-6789')
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
request = Net::HTTP::Get.new(uri)
request['X-API-Key'] = 'your_api_key_here'
request['Content-Type'] = 'application/json'
response = http.request(request)
puts JSON.pretty_generate(JSON.parse(response.body))using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
class Program
{
static async Task Main(string[] args)
{
using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-API-Key", "your_api_key_here");
var response = await client.GetAsync("https://api.apiverve.com/v1/taxidvalidator?taxid=123-45-6789");
response.EnsureSuccessStatusCode();
var responseBody = await response.Content.ReadAsStringAsync();
Console.WriteLine(responseBody);
}
}Authentication
The Tax ID Validator API requires authentication via API key. Include your API key in the request header:
X-API-Key: your_api_key_hereInteractive API Playground
Test the Tax ID Validator API directly in your browser with live requests and responses.
Parameters
The following parameters are available for the Tax ID Validator API:
Validate Tax ID
| Parameter | Type | Required | Description | Default | Example |
|---|---|---|---|---|---|
taxid | string | required | The US Tax ID to validate (SSN, EIN, or ITIN format) | - |
Response
The Tax ID Validator API returns responses in JSON, XML, YAML, and CSV formats:
Example Responses
{
"status": "ok",
"error": null,
"data": {
"valid": true,
"taxid": "123-45-6789",
"type": "SSN",
"type_full": "Social Security Number",
"format": "XXX-XX-XXXX",
"normalized": "123-45-6789",
"digits_only": "123456789",
"masked": "***-**-6789",
"last4": "6789",
"validation_details": {
"format_valid": true,
"area_number_valid": true,
"group_number_valid": true,
"serial_number_valid": true
},
"error": null
}
}<?xml version="1.0" encoding="UTF-8"?>
<response>
<status>ok</status>
<error xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
<data>
<valid>true</valid>
<taxid>123-45-6789</taxid>
<type>SSN</type>
<type_full>Social Security Number</type_full>
<format>XXX-XX-XXXX</format>
<normalized>123-45-6789</normalized>
<digits_only>123456789</digits_only>
<masked>***-**-6789</masked>
<last4>6789</last4>
<validation_details>
<format_valid>true</format_valid>
<area_number_valid>true</area_number_valid>
<group_number_valid>true</group_number_valid>
<serial_number_valid>true</serial_number_valid>
</validation_details>
<error xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
</data>
</response>
status: ok
error: null
data:
valid: true
taxid: 123-45-6789
type: SSN
type_full: Social Security Number
format: XXX-XX-XXXX
normalized: 123-45-6789
digits_only: '123456789'
masked: '***-**-6789'
last4: '6789'
validation_details:
format_valid: true
area_number_valid: true
group_number_valid: true
serial_number_valid: true
error: null
| key | value |
|---|---|
| valid | true |
| taxid | 123-45-6789 |
| type | SSN |
| type_full | Social Security Number |
| format | XXX-XX-XXXX |
| normalized | 123-45-6789 |
| digits_only | 123456789 |
| masked | ***-**-6789 |
| last4 | 6789 |
| validation_details | {format_valid:true,area_number_valid:true,group_number_valid:true,serial_number_valid:true} |
| error |
Response Structure
All API responses follow a consistent structure with the following fields:
| Field | Type | Description | Example |
|---|---|---|---|
status | string | Indicates whether the request was successful ("ok") or failed ("error") | ok |
error | string | null | Contains error message if status is "error", otherwise null | null |
data | object | null | Contains the API response data if successful, otherwise null | {...} |
Learn more about response formats →
Response Data Fields
When the request is successful, the data object contains the following fields:
| Field | Type | Sample Value | Description |
|---|---|---|---|
valid | boolean | Whether the Tax ID passed validation checks | |
taxid | string | The formatted Tax ID with standard formatting applied | |
typePremium | string | Abbreviated Tax ID type: SSN, EIN, or ITIN | |
type_fullPremium | string | Full name of Tax ID type like Social Security Number | |
formatPremium | string | Expected format pattern for the Tax ID type | |
normalized | string | Tax ID normalized to standard format with hyphens | |
digits_only | string | Tax ID with all non-numeric characters removed | |
masked | string | Tax ID with sensitive digits masked for privacy protection | |
last4 | string | Last four digits of the Tax ID only | |
validation_details | object | - | |
â”” format_validPremium | boolean | Whether the Tax ID matches the expected format | |
â”” area_number_validPremium | boolean | Whether SSN area number is valid (first three digits) | |
â”” group_number_validPremium | boolean | Whether SSN group number is valid (middle two digits) | |
â”” serial_number_validPremium | boolean | Whether SSN serial number is valid (last four digits) | |
error | object | Error message if validation failed, otherwise null |
Headers
Required and optional headers for Tax ID Validator API requests:
| Header Name | Required | Example Value | Description |
|---|---|---|---|
X-API-Key | required | your_api_key_here | Your APIVerve API key. Found in your dashboard under API Keys. |
Accept | optional | application/json | Specify response format: application/json (default), application/xml, or application/yaml |
User-Agent | optional | MyApp/1.0 | Identifies your application for analytics and debugging purposes |
X-Request-ID | optional | req_123456789 | Custom request identifier for tracking and debugging requests |
Cache-Control | optional | no-cache | Control caching behavior for the request and response |
GraphQL AccessALPHA
Access Tax ID Validator through GraphQL to combine it with other API calls in a single request. Query only the tax id validator data you need with precise field selection, and orchestrate complex data fetching workflows.
Credit Cost: Each API called in your GraphQL query consumes its standard credit cost.
POST https://api.apiverve.com/v1/graphqlquery {
taxidvalidator(
input: {
taxid: "123-45-6789"
}
) {
valid
taxid
type
type_full
format
normalized
digits_only
masked
last4
validation_details {
format_valid
area_number_valid
group_number_valid
serial_number_valid
}
error
}
}Note: Authentication is handled via the x-api-key header in your GraphQL request, not as a query parameter.
CORS Support
The Tax ID Validator API supports Cross-Origin Resource Sharing (CORS) with wildcard configuration, allowing you to call Tax ID Validator directly from browser-based applications without proxy servers.
| CORS Header | Value | Description |
|---|---|---|
Access-Control-Allow-Origin | * | Accepts requests from any origin |
Access-Control-Allow-Methods | * | Accepts any HTTP method |
Access-Control-Allow-Headers | * | Accepts any request headers |
Browser Usage: You can call Tax ID Validator directly from JavaScript running in the browser without encountering CORS errors. No proxy server or additional configuration needed.
Rate Limiting
Tax ID Validator API requests are subject to rate limiting based on your subscription plan. These limits ensure fair usage and maintain service quality for all Tax ID Validator users.
| Plan | Rate Limit | Description |
|---|---|---|
| Free | 5 requests/min | Hard rate limit enforced - exceeding will return 429 errors |
| Starter | No Limit | Production ready - standard traffic priority |
| Pro | No Limit | Production ready - preferred traffic priority |
| Mega | No Limit | Production ready - highest traffic priority |
Learn more about rate limiting →
Rate Limit Headers
When rate limits apply, each Tax ID Validator response includes headers to help you track your usage:
| Header | Description |
|---|---|
X-RateLimit-Limit | Maximum number of requests allowed per time window |
X-RateLimit-Remaining | Number of requests remaining in the current window |
X-RateLimit-Reset | Unix timestamp when the rate limit window resets |
Handling Rate Limits
Free Plan: When you exceed your rate limit, Tax ID Validator returns a 429 Too Many Requests status code. Your application should implement appropriate backoff logic to handle this gracefully.
Paid Plans: No rate limiting or throttling applied. All paid plans (Starter, Pro, Mega) are production-ready.
Best Practices for Tax ID Validator:
- Monitor the rate limit headers to track your Tax ID Validator usage (Free plan only)
- Cache tax id validator responses where appropriate to reduce API calls
- Upgrade to Pro or Mega for guaranteed no-throttle Tax ID Validator performance
Note: Tax ID Validator rate limits are separate from credit consumption. You may have credits remaining but still hit rate limits when using Tax ID Validator on Free tier.
Error Codes
The Tax ID Validator API uses standard HTTP status codes to indicate success or failure:
| Code | Message | Description | Solution |
|---|---|---|---|
200 | OK | Request successful, data returned | No action needed - request was successful |
400 | Bad Request | Invalid request parameters or malformed request | Check required parameters and ensure values match expected formats |
401 | Unauthorized | Missing or invalid API key | Include x-api-key header with valid API key from dashboard |
403 | Forbidden | API key lacks permission or insufficient credits | Check credit balance in dashboard or upgrade plan |
429 | Too Many Requests | Rate limit exceeded (Free: 5 req/min) | Implement request throttling or upgrade to paid plan |
500 | Internal Server Error | Server error occurred | Retry request after a few seconds, contact support if persists |
503 | Service Unavailable | API temporarily unavailable | Wait and retry, check status page for maintenance updates |
Learn more about error handling →
Need help? Contact support with your X-Request-ID for assistance.
Integrate Tax ID Validator with SDKs
Get started quickly with official Tax ID Validator SDKs for your preferred language. Each library handles authentication, request formatting, and error handling automatically.
Available for Node.js, Python, C#/.NET, and Android/Java. All SDKs are open source and regularly updated.
Integrate Tax ID Validator with No-Code API Tools
Connect the Tax ID Validator API to your favorite automation platform without writing code. Build workflows that leverage tax id validator data across thousands of apps.





All platforms use your same API key to access Tax ID Validator. Visit our integrations hub for step-by-step setup guides.
Frequently Asked Questions
How do I get an API key for Tax ID Validator?
How many credits does Tax ID Validator cost?
Each successful Tax ID Validator API call consumes credits based on plan tier. Check the pricing section above for the exact credit cost. Failed requests and errors don't consume credits, so you only pay for successful tax id validator lookups.
Can I use Tax ID Validator in production?
The free plan is for testing and development only. For production use of Tax ID Validator, upgrade to a paid plan (Starter, Pro, or Mega) which includes commercial use rights, no attribution requirements, and guaranteed uptime SLAs. All paid plans are production-ready.
Can I use Tax ID Validator from a browser?
What happens if I exceed my Tax ID Validator credit limit?
When you reach your monthly credit limit, Tax ID Validator API requests will return an error until you upgrade your plan or wait for the next billing cycle. You'll receive notifications at 80% and 95% usage to give you time to upgrade if needed.



