SDKs

Open Pay provides official SDKs for five languages plus a CLI tool. Every SDK handles HMAC-SHA256 request signing automatically, so you never have to compute signatures manually.

TypeScript

@openpay/sdk for Node.js and edge runtimes

Go

openlankapay-go-sdk for backend services

Python

openpay-sdk with async httpx support

PHP

openpay/sdk via Composer

Java

com.openpay:openpay-sdk for JVM applications

CLI

openpay command-line tool

Common Features

All SDKs share the same capabilities:

Feature	Description
Create Payments	Generate payment requests with amount, currency, and metadata
Checkout Sessions	Create hosted checkout pages with success/cancel URLs
Webhook Verification	Verify ED25519-signed webhook payloads
HMAC Authentication	Automatic request signing with your API key and secret
Error Handling	Typed errors with status codes and descriptive messages
Retry Logic	Automatic retries with exponential backoff for transient failures

Authentication

Every SDK uses HMAC-SHA256 to sign requests. You provide your API key (public identifier) and API secret (signing key), and the SDK handles the rest. The signature is computed as:

message = timestamp + method + path + body
signing_key = SHA256(api_secret)
signature = HMAC-SHA256(message, signing_key)

These headers are sent with each request:

Header	Value
`x-api-key`	Your API key (`ak_live_xxx`)
`x-timestamp`	Unix timestamp in milliseconds
`x-signature`	HMAC-SHA256 hex digest

Get your API key and secret from the Merchant Portal under Integrations.

Quick Comparison

TypeScript
Go
Python
PHP
Java

import { OpenPay } from "@openpay/sdk";

const client = new OpenPay({
  apiKey: process.env.OPENPAY_API_KEY!,
  apiSecret: process.env.OPENPAY_API_SECRET!,
});

client := openpay.NewClient(
    os.Getenv("OPENPAY_API_KEY"),
    os.Getenv("OPENPAY_API_SECRET"),
)

from openpay import OpenPayClient

client = OpenPayClient(
    api_key=os.environ["OPENPAY_API_KEY"],
    api_secret=os.environ["OPENPAY_API_SECRET"],
)

$client = new \OpenPay\OpenPayClient(
    apiKey: getenv('OPENPAY_API_KEY'),
    apiSecret: getenv('OPENPAY_API_SECRET'),
);

OpenPayClient client = OpenPayClient.builder()
    .apiKey(System.getenv("OPENPAY_API_KEY"))
    .apiSecret(System.getenv("OPENPAY_API_SECRET"))
    .build();

API Base URL

All SDKs default to the production API:

https://olp-api.nipuntheekshana.com

You can override this by passing a baseUrl option during client initialization if you are targeting a different environment.

​SDKs

TypeScript

Go

Python

PHP

Java

CLI

​Common Features

​Authentication

​Quick Comparison

​API Base URL

SDKs

Common Features

Authentication

Quick Comparison

API Base URL