README

PHP SDK for the KryptoExpress API.

This package is framework-agnostic. It works in plain PHP and can be used as the core layer for framework or CMS integrations, including a future WooCommerce plugin.

Install

composer require kryptoexpress/kryptoexpress-php

For PSR-18 mode install a PSR-18 client and PSR-17 factory, for example:

composer require symfony/http-client nyholm/psr7

Requirements

PHP 8.2 or newer
ext-json
ext-hash

Quick Start

<?php

use KryptoExpress\SDK\KryptoExpressClient;

$client = new KryptoExpressClient('your-api-key');

$payment = $client->payments()->createPayment(
    cryptoCurrency: 'BTC',
    fiatCurrency: 'USD',
    fiatAmount: 10.0,
    callbackUrl: 'https://merchant.example/callback',
    callbackSecret: 'shared-secret',
);

$wallet = $client->wallet()->get();
$prices = $client->currencies()->getPrices(['BTC', 'ETH'], 'USD');
$fiatCurrencies = $client->fiat()->list();

Client Methods

$client->payments()->create($request);
$client->payments()->createPayment(...);
$client->payments()->createDeposit(...);
$client->payments()->getByHash(...);

$client->wallet()->get();
$client->wallet()->withdraw(...);
$client->wallet()->calculate(...);
$client->wallet()->withdrawAll(...);
$client->wallet()->withdrawSingle(...);
$client->wallet()->calculateAll(...);
$client->wallet()->calculateSingle(...);

$client->currencies()->listAll();
$client->currencies()->listNative();
$client->currencies()->listStable();
$client->currencies()->getPrices(...);

$client->fiat()->list();

Payment Rules

PAYMENT requires fiatAmount.
DEPOSIT must not send fiatAmount.
Stablecoins support only PAYMENT.
Stablecoin payments are exact-payment only.
Client-side minimum amount validation is applied only to USD payments.
For USD, the minimum amount is 1.00.
Non-USD payments are sent to the API without local minimum threshold validation.

Fiat Conversion

The SDK no longer requires a fiat converter for normal non-USD payment creation. If you keep using a converter abstraction in your application, treat it as an optional extension rather than a required part of the default payment flow.

<?php

use KryptoExpress\SDK\ClientConfig;
use KryptoExpress\SDK\KryptoExpressClient;
use KryptoExpress\SDK\Rules\StaticFiatConverter;

$client = new KryptoExpressClient(
    'your-api-key',
    new ClientConfig(
        fiatConverter: new StaticFiatConverter([
            'EUR' => 0.91,
            'GBP' => 0.79,
        ]),
    ),
);

You can also disable the remaining USD client-side minimum validation:

<?php

use KryptoExpress\SDK\ClientConfig;
use KryptoExpress\SDK\KryptoExpressClient;

$client = new KryptoExpressClient(
    'your-api-key',
    new ClientConfig(validateMinimumAmounts: false),
);

Webhook Signatures

Header: X-Signature
Algorithm: HMAC-SHA512
Message: compact raw JSON body
Key: callbackSecret

<?php

$isValid = $client->webhook()->verify($rawBody, 'callback-secret', $_SERVER['HTTP_X_SIGNATURE'] ?? null);

Transport

NativeTransport is the default and works without extra runtime packages.
Psr18Transport can be used when you already have a PSR-18 client stack.

Using A PSR-18 Client

<?php

use KryptoExpress\SDK\KryptoExpressClient;
use Nyholm\Psr7\Factory\Psr17Factory;
use Symfony\Component\HttpClient\Psr18Client;

$client = KryptoExpressClient::withPsr18(
    'your-api-key',
    new Psr18Client(),
    new Psr17Factory(),
);

Notes

Practical docs say native coins are BTC, LTC, ETH, SOL, BNB, DOGE, while OpenAPI also includes TRX.
Practical docs list stablecoins on ERC20, BEP20, and SOL, while OpenAPI also includes USDT_TRC20.
OpenAPI examples for /cryptocurrency and /cryptocurrency/stable contain broader enums than the practical guide suggests.
The practical docs are authoritative for PAYMENT vs DEPOSIT, stablecoin semantics, minimum amount policy, and webhook signature behavior.

WooCommerce

This package does not include WordPress or WooCommerce code. A WooCommerce plugin should use this SDK as its core API layer and keep hooks, settings, gateway classes, callback routing, and order-status mapping in a separate integration package.

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