GST Certificate OCR API

The GST Certificate OCR API allows users to extract GST registration certificate details automatically from uploaded certificate images or documents using OCR technology. It retrieves structured information such as GST number, business name, trade name, registration date, address, taxpayer type, and other available GST details quickly and accurately in JSON format.

API Details

Request URL

POST

https://g99.in/api/ocr/gstocr

Request Body Parameters

Type	Name	Optional	Description
File	file	Required	Upload the GST Certificate image.

Request Header Parameters

Type	Name	Value / Description	Optional
String	Content-Type	multipart/form-data	Required

Sample Code

request.php

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => 'https://g99.in/api/ocr/gstocr',
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => '',
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 0,
  CURLOPT_FOLLOWLOCATION => true,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => 'POST',
  CURLOPT_POSTFIELDS => array('file'=> new CURLFILE(' --Uploaded File Path-- ')),
));

$response = curl_exec($curl);

curl_close($curl);
echo $response;

request.py

import requests

url = "https://g99.in/api/ocr/gstocr"

payload = {}
files=[
  ('file',('Screenshot 2026-03-27 171219.png',open(' --Uploaded File Path-- ','rb'),'image/png'))
]
headers = {}

response = requests.request("POST", url, headers=headers, data=payload, files=files)

print(response.text)

request.cs

var client = new HttpClient();
var request = new HttpRequestMessage(HttpMethod.Post, "https://g99.in/api/ocr/gstocr");
var content = new MultipartFormDataContent();
content.Add(new StreamContent(File.OpenRead(" --Uploaded File Path-- ")), "file", " --Uploaded File Path-- ");
request.Content = content;
var response = await client.SendAsync(request);
response.EnsureSuccessStatusCode();
Console.WriteLine(await response.Content.ReadAsStringAsync());

Response

HTTP status code 200

Key	Type	Description
gstin	String	GST Identification Number of the registered business.
legalName	String	Official legal name of the business or entity.
tradeName	String	Trade or business name used publicly.
constitution	String	Type of business entity such as Proprietorship, Company, LLP, etc.
address	String	Registered business address mentioned in the GST certificate.
type	String	Category or type of GST registration.
registered	String	GST registration date of the business.
expiry	String	Expiry date of the GST registration, if available.
issued	String	Date on which the GST certificate was issued.
approvingAuthority	String	Authority or officer who approved the GST registration.
jurisdiction	String	GST jurisdiction area assigned to the business.
provisional	String	Provisional GST registration or provisional ID details.
pan	String	PAN number linked with the GST registration.
tin	String	Taxpayer Identification Number associated with the business.
slr	String	Serial or reference number available in the GST certificate.

Sample Response

Sample response for valid document

response.json

{
  "valid": true,
  "message": null,
  "data": {
    "gstin": "12AABCD1111D1ZM",
    "legalName": "Guru Infotek Kerala",
    "tradeName": "Guru Infotek Kerala.",
    "constitution": "Private Limited Company",
    "address": "2nd Floor, 2nd cross street, kochi, Kerala",
    "type": "Regular",
    "registered": "30/03/2021",
    "expiry": null,
    "issued": "30/03/2021",
    "approvingAuthority": "Kerala",
    "jurisdiction": null,
    "provisional": true,
    "pan": "ABCDS1111D",
    "tin": "125xxxxxx016v",
    "slr": "125xxxxxxx16c"
  }
}

Error Response

Parameter	Type	Description
status	Number	Unique error codes for different errors. Always available.
message	String	Error message describing the error. Always Available.
error	Boolean	True / False for different errors. Always available.

Error Codes

HTTP Status	Error Code	Error Message
400	4001	Malformed data or missing required parameter values.
400	4002	File size exceeds 10MB limit.
400	4003	Only JPEG and PNG images are supported.
400	4004	Invalid or corrupted image.
400	4005	Minimum image size should be 200 X 200 pixels.
500	5001	Document processing service is currently unavailable. Please try again later.

Sample Error Response

response.json

{
  "message": "Invalid or corrupted image.",
  "status": 4004,
  "error": True
}

Constraints

Only JPEG, PNG images are supported.
Minimum image size is 200x200 png for better identification and parsing.
Maximum allowed image size is 10 MB.