💧 Water Bill OCR

1 ICper page

v1.0 Active Jul 2026 POST /ocr/v3/water-bill/file

Welcome to the Water Bill OCR API, part of iApp Any Documents OCR by iApp Technology Co., Ltd. Extracts billing data from Metropolitan Waterworks Authority (การประปานครหลวง) and Provincial Waterworks Authority (การประปาส่วนภูมิภาค) bills, including meter readings, consumption and VAT. Amounts are cross-checked arithmetically (subtotal + VAT = total) for reliability on low-quality images.

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Example Images (Click to try)

API Key

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Endpoint URL

cURL Command

Upload Water Bill

Getting Started

1. Prerequisites

   • An API key from iApp Technology
   • Document file: Water Bill (ใบแจ้งค่าน้ำประปา)
   • Supported file formats: PDF, JPG, JPEG, PNG, WEBP
   • Maximum file size: 50MB

2. Quick Start

   • Single POST with multipart/form-data
   • Structured JSON out, with a per-field confidence score
   • Each input page returns its own entry in docs, so a batch of documents can be sent in one request.

3. Key Features

   • Field-level extraction with confidence scoring
   • Thai and English output via target_lang
   • Optional raw OCR text via return_ocr
   • Handles photographs and scanned PDFs

4. Security & Compliance

   • GDPR and PDPA compliant
   • Secure API endpoints
   • No data retention after processing

How to get API Key?

Please visit API Key Management page to view your existing API key or request a new one.

API Endpoints

Endpoint	Method	Description	Cost
/ocr/v3/water-bill/file /v3/store/ocr/water-bill	POST	Extract billing data from Thai water bills (MWA / PWA)	1 IC per page

Both forms are equivalent. There is no base64 variant for this endpoint — file upload only.

Request

Request Headers

Header	Value	Required
apikey	Your iApp API key	Yes

Request Body (multipart/form-data)

Parameter	Type	Default	Description
file	File (repeatable)	—	Required. Document file. PDF pages are processed automatically.
return_ocr	Boolean	false	Include the raw OCR text in the response.
target_lang	String	th	Language of extracted values: th or en.
include_confidence	Boolean	true	Include a per-field confidence score (0.00–1.00).

cURL

curl -X POST "https://api.iapp.co.th/ocr/v3/water-bill/file" \
  -H "apikey: YOUR_API_KEY" \
  -F "file=@/path/to/document.pdf" \
  -F "target_lang=th" \
  -F "include_confidence=true"

Response

{
    "docs": [
        {
            "message": "success",
            "raw": {},
            "processed": {
                        "provider": "การประปานครหลวง",
                        "customer_name": null,
                        "customer_address": "32/14 ม.3 ตำบลท่าจีน อำเภอสามพราน จังหวัดนครปฐม 11130",
                        "account_number": "67983262",
                        "invoice_number": "192011-5",
                        "invoice_date": "12/02/2567",
                        "current_reading": 606,
                        "previous_reading": 567,
                        "consumption_cubic_meter": 39,
                        "water_usage_charge": 430.39,
                        "monthly_service_fee": 25.0,
                        "discount": 0.0,
                        "subtotal_before_vat": 461.24,
                        "vat_amount": 32.29,
                        "total_amount": 493.53,
                        "due_date": "22/02/2567"
            },
            "confidence": {
                        "provider": 0.95,
                        "customer_name": 0.95,
                        "customer_address": 0.95,
                        "account_number": 0.95,
                        "invoice_number": 0.95,
                        "invoice_date": 0.95
            },
            "process_ms": 4120
        }
    ],
    "docs_count": 1,
    "process_ms": 4300
}

The iapp-input-pages response header reports the number of billed pages.

Supported Fields

Field	Type	Description
provider	String	Issuing authority, e.g. การประปานครหลวง
customer_name	String	Water customer name
customer_address	String	Service address
account_number	String	Water customer registration number
invoice_number	String	Bill number
invoice_date	String	Bill issue date
current_reading	Number	Current water meter reading
previous_reading	Number	Previous water meter reading
consumption_cubic_meter	Number	Water consumed (m³)
water_usage_charge	Number	Water usage charge (THB)
monthly_service_fee	Number	Monthly service fee (THB)
discount	Number	Discount (THB)
subtotal_before_vat	Number	Subtotal before VAT (THB)
vat_amount	Number	VAT amount (THB)
total_amount	Number	Total amount payable (THB)
due_date	String	Payment due date

Error Handling

Status	Meaning
400	Unsupported file extension, or file larger than 50MB
401	Missing or invalid apikey
402	Insufficient credit balance
404	Unknown document type in the URL
422	No file attached to the request
500	Processing error — the response contains an error code to quote to support

Code Examples

Python

import requests

url = "https://api.iapp.co.th/ocr/v3/water-bill/file"
headers = {"apikey": "YOUR_API_KEY"}
files = {"file": open("document.pdf", "rb")}
data = {"target_lang": "th", "include_confidence": "true"}

response = requests.post(url, headers=headers, files=files, data=data)
result = response.json()
print(result["docs"][0]["processed"])
print(result["docs"][0]["confidence"])

JavaScript

const form = new FormData();
form.append("file", fileInput.files[0]);
form.append("target_lang", "th");
form.append("include_confidence", "true");

const res = await fetch("https://api.iapp.co.th/ocr/v3/water-bill/file", {
  method: "POST",
  headers: { apikey: "YOUR_API_KEY" },
  body: form,
});
const result = await res.json();
console.log(result.docs[0].processed);

PHP

<?php
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://api.iapp.co.th/ocr/v3/water-bill/file");
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["apikey: YOUR_API_KEY"]);
curl_setopt($ch, CURLOPT_POSTFIELDS, [
    "file" => new CURLFile("/path/to/document.pdf"),
    "target_lang" => "th",
]);
$response = curl_exec($ch);
curl_close($ch);
echo $response;

Java

OkHttpClient client = new OkHttpClient();

RequestBody body = new MultipartBody.Builder()
    .setType(MultipartBody.FORM)
    .addFormDataPart("file", "document.pdf",
        RequestBody.create(new File("/path/to/document.pdf"),
            MediaType.parse("application/pdf")))
    .addFormDataPart("target_lang", "th")
    .build();

Request request = new Request.Builder()
    .url("https://api.iapp.co.th/ocr/v3/water-bill/file")
    .addHeader("apikey", "YOUR_API_KEY")
    .post(body)
    .build();

try (Response response = client.newCall(request).execute()) {
    System.out.println(response.body().string());
}

Swift

let url = URL(string: "https://api.iapp.co.th/ocr/v3/water-bill/file")!
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.setValue("YOUR_API_KEY", forHTTPHeaderField: "apikey")

let boundary = UUID().uuidString
request.setValue("multipart/form-data; boundary=\(boundary)",
                 forHTTPHeaderField: "Content-Type")

var data = Data()
let fileData = try Data(contentsOf: URL(fileURLWithPath: "/path/to/document.pdf"))
data.append("--\(boundary)\r\n".data(using: .utf8)!)
data.append("Content-Disposition: form-data; name=\"file\"; filename=\"document.pdf\"\r\n\r\n".data(using: .utf8)!)
data.append(fileData)
data.append("\r\n--\(boundary)--\r\n".data(using: .utf8)!)

URLSession.shared.uploadTask(with: request, from: data) { responseData, _, _ in
    if let responseData, let json = String(data: responseData, encoding: .utf8) {
        print(json)
    }
}.resume()

Kotlin

val client = OkHttpClient()

val body = MultipartBody.Builder()
    .setType(MultipartBody.FORM)
    .addFormDataPart(
        "file", "document.pdf",
        File("/path/to/document.pdf").asRequestBody("application/pdf".toMediaType())
    )
    .addFormDataPart("target_lang", "th")
    .build()

val request = Request.Builder()
    .url("https://api.iapp.co.th/ocr/v3/water-bill/file")
    .addHeader("apikey", "YOUR_API_KEY")
    .post(body)
    .build()

client.newCall(request).execute().use { response ->
    println(response.body?.string())
}

Dart

import 'package:http/http.dart' as http;

final request = http.MultipartRequest(
  'POST',
  Uri.parse('https://api.iapp.co.th/ocr/v3/water-bill/file'),
);
request.headers['apikey'] = 'YOUR_API_KEY';
request.fields['target_lang'] = 'th';
request.files.add(
  await http.MultipartFile.fromPath('file', '/path/to/document.pdf'),
);

final response = await request.send();
print(await response.stream.bytesToString());

Limitations & Best Practices

Limitations

• Maximum file size 50MB per request
• Supported formats: PDF, JPG, JPEG, PNG, WEBP
• Accuracy depends on image quality — heavily degraded scans, glare and handwriting over printed values reduce field-level accuracy
• Extraction is limited to the fields listed above

Best Practices

• Prefer the original PDF over a photograph where you have one
• Photograph the whole document, square-on and in even lighting
• Use at least 300 DPI for scans
• Check the confidence score per field and route low-confidence values to manual review
• Send multiple documents in one request where supported to reduce round trips

Accuracy & Performance

Field-level extraction accuracy measured on the internal ChindaOCR-M3 golden evaluation set — visually re-verified labels over real Thai documents, including low-resolution photographs and bills partly obscured by handwriting.

Document Type	Docs	Fields	Accuracy
Water Bill	5	25	100%
Overall, all six document types	25	147	98.6%

Support

Need help? Contact us:

• Email: sale@iapp.co.th
• Phone: 086-322-5858
• Discord: iApp Technology