📄 Thai Tax Deduction Certificate OCR 🆕
📄 ใบรับรองการหักภาษี ณ ที่จ่ายของไทย / ใบรับรอง ภงด. ทวิ 50
Welcome to the Thai Tax Deduction Certificate OCR API, an AI-powered solution developed by iApp Technology Co., Ltd. for extracting data from Thai tax deduction certificates. This documentation will help you integrate and use our OCR service effectively.
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Example Images (Click to try)

Demo key is limited to 10 requests per day per IP
Click here to get your API key
Getting Started
-
Prerequisites
- An API key from iApp Technology
- Thai tax deduction certificate images
- Supported file formats: JPEG, JPG, PNG, HEIC, HEIF, PDF
- Maximum file size: 10MB
-
Quick Start
- Fast processing (5-10 seconds per document)
- High accuracy text extraction
- Support for multiple file formats
-
Key Features
- Detailed field extraction including:
- Certificate details (ID, date)
- Payer information (name, address, tax ID)
- Payee information (name, address, tax ID)
- Income details (type, amount, tax withheld)
- Financial summary (total income, total tax withheld)
- Support for both single-page and multi-page documents (PDF)
- Option to return original OCR text and processed images
- Flexible JSON response format with detailed field extraction
- Detailed field extraction including:
-
Security & Compliance
- GDPR and PDPA compliant
- Secure API endpoints
- No data retention after processing
Our API is designed to handle various tax deduction certificate formats and layouts commonly used in Thailand. The post-processing AI model is trained to understand Thai tax document structures and can reliably extract information even from noisy or poorly scanned documents.
Example
Here's a sample Thai tax deduction certificate and its extracted data:

Request:
cURL
curl -X POST https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/file \
-H apikey: YOUR_API_KEY \
-F file=@/path/to/certificate.jpg \
-F return_image=false \
-F return_ocr=false
Please visit API Portal to view your existing API key or request a new one.
Response:
{
"message": "success",
"raw": {},
"processed": {
"documentType": "หนังสือรับรองการหักภาษี ณ ที่จ่าย",
"documentForm": "ภ.ง.ด.3",
"bookNumber": "TX63XXXX",
"documentNumber": null,
"taxDeductor": {
"name": "บริษัท XXXXXXXXXXXXXXXXXXXX จำกัด",
"taxId": "010XXXXXXXX64",
"address": "XXXX XXXXXX XXXXXXXX เขตจอมทอง กรุงเทพมหานคร 10150"
},
"taxpayer": {
"name": "นายXXXXX เป็นตัวอย่าง",
"taxId": "31XXXXXXXX123",
"address": "XXXX XXXXXX XXXXXXXX เขตสาทร กรุงเทพมหานคร"
},
"paymentTypes": [
{
"paymentDate": "02/09/63",
"amount": XXXXX.XX,
"withholdingTax": XXXX.XX
}
],
"totalAmount": XXXXX.XX,
"totalTax": XXXX.XX,
"socialSecurity": {
"amount": null,
"year": null
},
"taxPayerMethod": "ออกภาษีให้ตลอดไป"
},
"template": "tax-deduction-certificate-prd",
"iapp": {
"page": 0,
"char": 3260
},
"process_ms": 46649
}
Features & Capabilities
Core Features
-
Document Processing
- High accuracy text extraction and field recognition
- Thai language support
- Fast processing time of 25-30 seconds per document
- Multi-format support (JPEG, JPG, PNG, HEIC, HEIF, PDF)
- Multi-page document handling
- Option to return original OCR text and processed images
- GDPR and PDPA compliant processing
-
Data Extraction
- Flexible JSON response format with detailed field extraction
Supported Fields
Field | Type | Description |
---|---|---|
documentType | String | Type of tax document |
documentForm | String | Form type (ภ.ง.ด.1ก, ภ.ง.ด.1ก พิเศษ, ภ.ง.ด.2, ภ.ง.ด.3, ภ.ง.ด.2ก, ภ.ง.ด.3ก, ภ.ง.ด.53) |
bookNumber | String | Book number of document |
documentNumber | String | Document number |
taxDeductor.name | String | Name of tax deductor |
taxDeductor.taxId | String | Tax ID of tax deductor |
taxDeductor.address | String | Address of tax deductor |
taxpayer.name | String | Name of taxpayer |
taxpayer.taxId | String | Tax ID of taxpayer |
taxpayer.address | String | Address of taxpayer |
paymentTypes[].paymentDate | String | Date of payment |
paymentTypes[].amount | Number | Payment amount |
paymentTypes[].withholdingTax | Number | Withholding tax amount |
totalAmount | Number | Total payment amount |
totalTax | Number | Total withholding tax amount |
socialSecurity.amount | Number | Social security amount |
socialSecurity.year | Number | Social security year |
taxPayerMethod | String | Tax payment method (หักภาษี ณ ที่จ่าย, ออกภาษีให้ตลอดไป, ออกภาษีให้ครั้งเดียว, อื่นๆ) |
API Reference
Welcome to the Thai Tax Deduction Certificate OCR API, a powerful tool for converting Thai tax deduction certificates into structured JSON data. This API leverages advanced OCR and AI technologies to extract key information such as document details, tax deductor and taxpayer data, payment information, and tax amounts.
Recognizing Tax Deduction Certificate
There are two endpoints available for processing tax deduction certificates:
1. File Upload
POST https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/file
Request Headers
Name | Type | Required | Description |
---|---|---|---|
apikey | string | Yes | Your API key |
Request Body (multipart/form-data)
Parameter | Type | Required | Description |
---|---|---|---|
file | file | Yes | Tax certificate image (JPEG, PNG) or PDF document |
return_image | boolean | No | Include base64 encoded image in response (default: false) |
return_ocr | boolean | No | Include raw OCR text in response (default: false) |
Supported File Types
- Images: JPEG, PNG, HEIC, HEIF
- Documents: PDF (up to 10 pages)
Response Format
{
"message": "success",
"raw": {
"image": "string", // Base64 encoded, only if return_image=true
"text": "string" // Only if return_ocr=true
},
"processed": {
"documentType": "string",
"documentForm": "string",
"bookNumber": "string",
"documentNumber": "string",
"taxDeductor": {
"name": "string",
"taxId": "string",
"address": "string"
},
"taxpayer": {
"name": "string",
"taxId": "string",
"address": "string"
},
"paymentTypes": [
{
"paymentDate": "string",
"amount": "number",
"withholdingTax": "number"
}
],
"totalAmount": "number",
"totalTax": "number",
"socialSecurity": {
"amount": "number",
"year": "number"
},
"taxPayerMethod": "string"
},
"template": "tax-deduction-certificate-prd",
"iapp": {
"page": "number",
"char": "number"
},
"process_ms": "number"
}
2. Base64 Image
POST https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/base64
Request Headers
Name | Type | Required | Description |
---|---|---|---|
apikey | string | Yes | Your API key |
Request Body
You can send the base64 data either as JSON or form data:
JSON Format:
{
"base64_string": "string", // Base64 encoded image data
"return_image": false, // Optional
"return_ocr": false // Optional
}
Form Data Format:
Parameter | Type | Required | Description |
---|---|---|---|
base64_string | string | Yes | Base64 encoded image data |
return_image | boolean | No | Include base64 encoded image in response (default: false) |
return_ocr | boolean | No | Include raw OCR text in response (default: false) |
Response Format
Same as file upload endpoint
Code Examples
Python (File Upload)
import requests
apiKey = 'YOUR_API_KEY'
filePath = '/path/to/tax-deduction-certificate-prd.jpg'
url = "https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/file"
headers = {'apikey': apiKey}
files = {'file': ('tax-deduction-certificate-prd.jpg', open(filePath, 'rb'), 'image/jpeg')}
data = {'return_image': 'false', 'return_ocr': 'false'}
response = requests.post(url, headers=headers, files=files, data=data)
print(response.json())
Python (Base64)
import requests
import base64
apiKey = 'YOUR_API_KEY'
filePath = '/path/to/tax-deduction-certificate-prd.jpg'
url = "https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/base64"
# Read image file and convert to base64
with open(filePath, 'rb') as image_file:
base64_string = base64.b64encode(image_file.read()).decode()
headers = {
'apikey': apiKey,
'Content-Type': 'application/json'
}
data = {
'base64_string': base64_string,
'return_image': False,
'return_ocr': False
}
response = requests.post(url, headers=headers, json=data)
print(response.json())
Javascript (File Upload)
const axios = require("axios")
const FormData = require("form-data")
const fs = require("fs")
const apiKey = "YOUR_API_KEY"
const filePath = "/path/to/tax-deduction-certificate-prd.jpg"
const url = "https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/file"
const form = new FormData()
form.append("file", fs.createReadStream(filePath))
form.append("return_image", "false")
form.append("return_ocr", "false")
try {
const response = await axios.post(url, form, {
headers: {
...form.getHeaders(),
apikey: apiKey,
},
})
return response.data
} catch (error) {
throw error
}
Javascript (Base64)
const axios = require("axios")
const fs = require("fs")
const apiKey = "YOUR_API_KEY"
const filePath = "/path/to/tax-deduction-certificate-prd.jpg"
const url = "https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/base64"
// Read image file and convert to base64
const base64String = fs.readFileSync(filePath, { encoding: "base64" })
const data = {
base64_string: base64String,
return_image: false,
return_ocr: false,
}
try {
const response = await axios.post(url, data, {
headers: {
"Content-Type": "application/json",
apikey: apiKey,
},
})
return response.data
} catch (error) {
throw error
}
PHP (File Upload)
$url = 'https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/file';
$apiKey = 'YOUR_API_KEY';
$filePath = '/path/to/tax-deduction-certificate-prd.jpg';
$headers = array(
'apikey: ' . $apiKey
);
$postFields = array(
'file' => new CURLFile($filePath),
'return_image' => 'false',
'return_ocr' => 'false'
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $postFields);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
$response = curl_exec($ch);
curl_close($ch);
echo $response;
PHP (Base64)
$url = 'https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/base64';
$apiKey = 'YOUR_API_KEY';
$filePath = '/path/to/tax-deduction-certificate-prd.jpg';
// Read image file and convert to base64
$base64String = base64_encode(file_get_contents($filePath));
$data = array(
'base64_string' => $base64String,
'return_image' => false,
'return_ocr' => false
);
$headers = array(
'Content-Type: application/json',
'apikey: ' . $apiKey
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
$response = curl_exec($ch);
curl_close($ch);
echo $response;
Swift (File Upload)
import Foundation
let url = URL(string: "https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/file")!
let filePath = "/path/to/tax-deduction-certificate-prd.jpg"
let apiKey = "YOUR_API_KEY"
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.setValue(apiKey, forHTTPHeaderField: "apikey")
let boundary = UUID().uuidString
request.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")
var body = Data()
body.append("--\(boundary)\r\n".data(using: .utf8)!)
body.append("Content-Disposition: form-data; name=\"file\"; filename=\"tax-deduction-certificate-prd.jpg\"\r\n".data(using: .utf8)!)
body.append("Content-Type: image/jpeg\r\n\r\n".data(using: .utf8)!)
body.append(try! Data(contentsOf: URL(fileURLWithPath: filePath)))
body.append("\r\n--\(boundary)\r\n".data(using: .utf8)!)
body.append("Content-Disposition: form-data; name=\"return_image\"\r\n\r\nfalse\r\n".data(using: .utf8)!)
body.append("--\(boundary)\r\n".data(using: .utf8)!)
body.append("Content-Disposition: form-data; name=\"return_ocr\"\r\n\r\nfalse\r\n".data(using: .utf8)!)
body.append("--\(boundary)--\r\n".data(using: .utf8)!)
request.httpBody = body
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else {
print("Error: \(error?.localizedDescription ?? "Unknown error")")
return
}
print(String(data: data, encoding: .utf8)!)
}
task.resume()
Swift (Base64)
import Foundation
let url = URL(string: "https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/base64")!
let filePath = "/path/to/tax-deduction-certificate-prd.jpg"
let apiKey = "YOUR_API_KEY"
// Read image file and convert to base64
guard let imageData = try? Data(contentsOf: URL(fileURLWithPath: filePath)) else {
print("Error reading file")
return
}
let base64String = imageData.base64EncodedString()
let parameters: [String: Any] = [
"base64_string": base64String,
"return_image": false,
"return_ocr": false
]
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.setValue(apiKey, forHTTPHeaderField: "apikey")
request.httpBody = try? JSONSerialization.data(withJSONObject: parameters)
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else {
print("Error: \(error?.localizedDescription ?? "Unknown error")")
return
}
print(String(data: data, encoding: .utf8)!)
}
task.resume()
Kotlin (File Upload)
import okhttp3.*
import java.io.File
val client = OkHttpClient()
val apiKey = "YOUR_API_KEY"
val filePath = "/path/to/tax-deduction-certificate-prd.jpg"
val url = "https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/file"
val file = File(filePath)
val requestBody = MultipartBody.Builder()
.setType(MultipartBody.FORM)
.addFormDataPart("file", file.name, RequestBody.create(MediaType.parse("image/jpeg"), file))
.addFormDataPart("return_image", "false")
.addFormDataPart("return_ocr", "false")
.build()
val request = Request.Builder()
.url(url)
.post(requestBody)
.addHeader("apikey", apiKey)
.build()
client.newCall(request).enqueue(object : Callback {
override fun onFailure(call: Call, e: IOException) {
e.printStackTrace()
}
override fun onResponse(call: Call, response: Response) {
response.use {
if (!response.isSuccessful) throw IOException("Unexpected code $response")
println(response.body()?.string())
}
}
})
Kotlin (Base64)
import okhttp3.*
import java.io.File
import android.util.Base64
import org.json.JSONObject
fun processBase64Image() {
val client = OkHttpClient()
val apiKey = "YOUR_API_KEY"
val filePath = "/path/to/tax-deduction-certificate-prd.jpg"
val url = "https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/base64"
// Read file and convert to base64
val file = File(filePath)
val bytes = file.readBytes()
val base64String = Base64.encodeToString(bytes, Base64.DEFAULT)
val json = JSONObject()
json.put("base64_string", base64String)
json.put("return_image", false)
json.put("return_ocr", false)
val requestBody = RequestBody.create(
MediaType.parse("application/json"),
json.toString()
)
val request = Request.Builder()
.url(url)
.post(requestBody)
.addHeader("Content-Type", "application/json")
.addHeader("apikey", apiKey)
.build()
client.newCall(request).enqueue(object : Callback {
override fun onFailure(call: Call, e: IOException) {
e.printStackTrace()
}
override fun onResponse(call: Call, response: Response) {
response.use {
if (!response.isSuccessful) throw IOException("Unexpected code $response")
println(response.body()?.string())
}
}
})
}
Java (File Upload)
import okhttp3.*;
import java.io.File;
import java.io.IOException;
public class Main {
public static void main(String[] args) {
OkHttpClient client = new OkHttpClient();
String apiKey = "YOUR_API_KEY";
String url = "https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/file";
String filePath = "/path/to/tax-deduction-certificate-prd.jpg";
try {
// Read file and convert to base64
byte[] fileContent = Files.readAllBytes(new File(filePath).toPath());
String base64String = Base64.getEncoder().encodeToString(fileContent);
JSONObject json = new JSONObject();
json.put("base64_string", base64String);
json.put("return_image", false);
json.put("return_ocr", false);
RequestBody requestBody = RequestBody.create(
MediaType.parse("application/json"),
json.toString()
);
Request request = new Request.Builder()
.url(url)
.post(requestBody)
.addHeader("Content-Type", "application/json")
.addHeader("apikey", apiKey)
.build();
client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
e.printStackTrace();
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);
System.out.println(response.body().string());
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
}
Java (Base64)
import okhttp3.*;
import java.io.File;
import java.io.IOException;
import java.util.Base64;
import java.nio.file.Files;
import org.json.JSONObject;
public class Main {
public static void main(String[] args) {
OkHttpClient client = new OkHttpClient();
String apiKey = "YOUR_API_KEY";
String url = "https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/base64";
String filePath = "/path/to/tax-deduction-certificate-prd.jpg";
try {
// Read file and convert to base64
byte[] fileContent = Files.readAllBytes(new File(filePath).toPath());
String base64String = Base64.getEncoder().encodeToString(fileContent);
JSONObject json = new JSONObject();
json.put("base64_string", base64String);
json.put("return_image", false);
json.put("return_ocr", false);
RequestBody requestBody = RequestBody.create(
MediaType.parse("application/json"),
json.toString()
);
Request request = new Request.Builder()
.url(url)
.post(requestBody)
.addHeader("Content-Type", "application/json")
.addHeader("apikey", apiKey)
.build();
client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
e.printStackTrace();
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);
System.out.println(response.body().string());
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
}
Dart (File Upload)
import 'dart:convert';
import 'dart:io';
import 'package:http/http.dart' as http;
String url = 'https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/file';
String filePath = '/path/to/tax-deduction-certificate-prd.jpg';
String apiKey = 'YOUR_API_KEY';
void main() async {
var url = Uri.parse(url);
var request = http.MultipartRequest('POST', url)
..headers['apikey'] = apiKey
..files.add(await http.MultipartFile.fromPath('file', filePath))
..fields['return_image'] = 'false'
..fields['return_ocr'] = 'false';
var response = await request.send();
if (response.statusCode == 200) {
var responseData = await response.stream.bytesToString();
print(responseData);
} else {
print('Error: ${response.statusCode}');
}
}
Dart (Base64)
import 'dart:convert';
import 'dart:io';
import 'package:http/http.dart' as http;
String url = 'https://api.iapp.co.th/ocr/v3/tax-deduction-certificate-prd/base64';
String filePath = '/path/to/tax-deduction-certificate-prd.jpg';
String apiKey = 'YOUR_API_KEY';
void main() async {
var url = Uri.parse(url);
var request = http.MultipartRequest('POST', url)
..headers['apikey'] = apiKey
..fields['return_image'] = 'false'
..fields['return_ocr'] = 'false';
// Read image file and convert to base64
File file = File(filePath);
List<int> fileBytes = await file.readAsBytes();
String base64String = base64Encode(fileBytes);
request.fields['base64_string'] = base64String;
var response = await request.send();
if (response.statusCode == 200) {
var responseData = await response.stream.bytesToString();
print(responseData);
} else {
print('Error: ${response.statusCode}');
}
}
Limitations & Best Practices
Limitations
- Maximum file size: 10MB
- Supported language: Thai
- PDF files: Up to 10 pages
- Rate limit: 10 requests per second per API key
Best Practices
- Ensure good image quality for optimal results
- Use JPEG or PNG format for images
- Implement error handling for failed requests
- Cache responses when processing the same document multiple times
- Set appropriate timeouts for large files
Accuracy & Performance
Overall Accuracy
Based on our benchmark dataset of 5,000 Thai tax deduction certificates:
Field Type | Accuracy (%) | Notes |
---|---|---|
Certificate Numbers | 99.5% | Including certificate IDs |
Amounts | 99.8% | Currency values and totals |
Dates | 99.0% | Various Thai date formats |
Tax IDs | 99.7% | Both individual and corporate |
Overall | 99.5% | Weighted average |
Processing Speed
- Average processing time: 25-30 seconds
- 95th percentile: 45 seconds
- Maximum processing time: 67 seconds
Factors Affecting Accuracy
-
Image Quality
- Resolution (minimum 300 DPI recommended)
- Lighting conditions
- Image focus and clarity
-
Document Condition
- Physical damage
- Fading or wear
- Handwritten modifications
-
Document Format
- Standard formats: 99%+ accuracy
- Non-standard layouts: 95%+ accuracy
- Handwritten elements: 90%+ accuracy
History
Our model is continuously trained on new data to improve accuracy:
Version | Release Date | Accuracy | Key Improvements |
---|---|---|---|
3.0 | 2024-12-27 | 99.5% | Base version |
Pricing
AI API Service Name | Pricing | On-Premise |
---|---|---|
Thai Tax Deduction Certificate OCR | 1 IC/Page | Contact |