The following project contains examples of integrating with PayU Gateway using OpenPayU PHP library.
Configure config.php with your sandbox API keys or use default values:
OpenPayU_Configuration::setEnvironment('sandbox');
OpenPayU_Configuration::setMerchantPosId('37857');
OpenPayU_Configuration::setPosAuthKey('ArJmhmF');
OpenPayU_Configuration::setClientId('37857');
OpenPayU_Configuration::setClientSecret('64dec4280702424aeea05ae85d20e15e');
OpenPayU_Configuration::setSignatureKey('a8e58d7c77722ceb73fa3fe43bf9cd53');