Face Comparison - Singapay Documentation

Face Comparison

curl --request POST \
  --url https://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "request_id": "TXN-20260727-001",
  "first_image": "/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...",
  "second_image": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="
}
'

import requests

url = "https://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison"

payload = {
    "request_id": "TXN-20260727-001",
    "first_image": "/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...",
    "second_image": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    request_id: 'TXN-20260727-001',
    first_image: '/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...',
    second_image: 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=='
  })
};

fetch('https://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison', 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://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison",
  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([
    'request_id' => 'TXN-20260727-001',
    'first_image' => '/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...',
    'second_image' => 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=='
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($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://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison"

	payload := strings.NewReader("{\n  \"request_id\": \"TXN-20260727-001\",\n  \"first_image\": \"/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...\",\n  \"second_image\": \"iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	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://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"request_id\": \"TXN-20260727-001\",\n  \"first_image\": \"/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...\",\n  \"second_image\": \"iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"request_id\": \"TXN-20260727-001\",\n  \"first_image\": \"/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...\",\n  \"second_image\": \"iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==\"\n}"

response = http.request(request)
puts response.read_body

{
  "code": "SUCCESS",
  "message": "OK",
  "data": {
    "first_face": {
      "id": "1",
      "left": 854.12,
      "top": 198.9,
      "right": 1008.29,
      "bottom": 389.44,
      "gender": "FEMALE"
    },
    "second_face": {
      "id": "2",
      "left": 107.53,
      "top": 148.77,
      "right": 375.04,
      "bottom": 536.12,
      "gender": "FEMALE"
    },
    "similarity": 20.18
  },
  "request_id": "TXN-20260727-001",
  "pricing": "PAID"
}

Face Comparison

Compares first_image with second_image and returns a similarity score plus bounding boxes.

A scored comparison (SUCCESS) and billed detection outcomes (FACE_NOT_FOUND, FIRST_FACE_NOT_FOUND, SECOND_FACE_NOT_FOUND, MULTIPLE_FACES_DETECTED) are billed (pricing=PAID). Validation errors and service failures are not billed (pricing=FREE).

This feature must be enabled on your account. If it is not, the API returns UNAUTHORIZED.

Outcomes

Result	Response
Faces compared	`code=SUCCESS`, `data.first_face` / `data.second_face` bounding boxes, `data.similarity`, `pricing=PAID`
No face / multiple faces	`code` is the vendor detection code, `pricing=PAID` (no `data`)
Face quality rejected by vendor	`code=CLIENT_ERROR`, `pricing=FREE`
Temporary service issue	`code=SERVER_ERROR`, `pricing=FREE`
Invalid images or `request_id`	`code=CLIENT_ERROR`, `pricing=FREE`
Same `request_id` with different images	`code=DUPLICATE_REFERENCE`, `pricing=FREE`
Missing token, feature not enabled, or IP not allowlisted	`code=UNAUTHORIZED`, `pricing=FREE`
Prepaid balance too low	`code=INSUFFICIENT_BALANCE`, `pricing=FREE`

Images

JPEG and PNG only, 5 MB or smaller per file. Send them either as:

application/json — first_image and second_image are raw base64 (no line breaks, no data:image/… prefix)
multipart/form-data — request_id as a text field, first_image and second_image as file parts (the same field names)

Do not mix the two encodings in one request.

Idempotency

Use a unique request_id for each new comparison (UUID v4 is recommended). Repeating the same request_id with the same images returns the original result and is billed once — unless the previous attempt did not complete, in which case the comparison runs again. Different images with the same request_id return DUPLICATE_REFERENCE.

POST

api

kyc

face-comparison

Face Comparison

curl --request POST \
  --url https://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "request_id": "TXN-20260727-001",
  "first_image": "/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...",
  "second_image": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="
}
'

import requests

url = "https://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison"

payload = {
    "request_id": "TXN-20260727-001",
    "first_image": "/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...",
    "second_image": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    request_id: 'TXN-20260727-001',
    first_image: '/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...',
    second_image: 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=='
  })
};

fetch('https://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison', 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://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison",
  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([
    'request_id' => 'TXN-20260727-001',
    'first_image' => '/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...',
    'second_image' => 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=='
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($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://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison"

	payload := strings.NewReader("{\n  \"request_id\": \"TXN-20260727-001\",\n  \"first_image\": \"/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...\",\n  \"second_image\": \"iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	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://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"request_id\": \"TXN-20260727-001\",\n  \"first_image\": \"/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...\",\n  \"second_image\": \"iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://sandbox-apigw.singapay.id/api/v1/kyc/face-comparison")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"request_id\": \"TXN-20260727-001\",\n  \"first_image\": \"/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg...\",\n  \"second_image\": \"iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==\"\n}"

response = http.request(request)
puts response.read_body

{
  "code": "SUCCESS",
  "message": "OK",
  "data": {
    "first_face": {
      "id": "1",
      "left": 854.12,
      "top": 198.9,
      "right": 1008.29,
      "bottom": 389.44,
      "gender": "FEMALE"
    },
    "second_face": {
      "id": "2",
      "left": 107.53,
      "top": 148.77,
      "right": 375.04,
      "bottom": 536.12,
      "gender": "FEMALE"
    },
    "similarity": 20.18
  },
  "request_id": "TXN-20260727-001",
  "pricing": "PAID"
}

Authorizations

Authorization

string

header

required

Access token from POST /api/v1/kyc/auth/get-auth-token. Valid for one hour.

Body

request_id

string

required

Your unique reference for this comparison. Use a new UUID for each new check. Sending the same key with the same images returns the original result and is billed once.

Example:

"TXN-20260727-001"

first_image

string

required

First image (typically a selfie) as raw base64 (JPEG or PNG). No line breaks and no data:image/… prefix. Maximum 5 MB after decoding.

Example:

"/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAg..."

second_image

string

required

Second image (typically an ID-card portrait) as raw base64 (JPEG or PNG). No line breaks and no data:image/… prefix. Maximum 5 MB after decoding.

Example:

"iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="

Response

Comparison finished and billed (pricing=PAID). SUCCESS includes data (boxes + similarity). Detection codes (FACE_NOT_FOUND and related) have no data.

Option 1
Option 2

code

enum<string>

required

A scored comparison finished. Bounding boxes and similarity are in data.

Available options:

SUCCESS

Example:

"SUCCESS"

message

enum<string>

required

Always OK. Use code, not this field, to branch.

Available options:

OK

Example:

"OK"

data

object

required

Show child attributes

request_id

string

required

The request_id you sent.

Example:

"TXN-20260727-001"

pricing

enum<string>

required

A scored comparison is always billed.

Available options:

PAID

Example:

"PAID"