epoint-go

Go client for the epoint.az payment gateway.

Covers all 30 documented endpoints: payments, saved cards, refunds and payouts, split payments, pre-authorisation, installments, wallets, Apple Pay and Google Pay, invoices, and B2B transfers. No dependencies outside the standard library.

go get github.com/martian56/epoint-go

Quick start

package main

import (
	"context"
	"fmt"

	epoint "github.com/martian56/epoint-go"
)

func main() {
	client := epoint.New("i000000001", "your-private-key")

	payment, err := client.CreatePayment(context.Background(), 30.75, "order-1", &epoint.PaymentOptions{
		Description: "Test order",
	})
	if err != nil {
		panic(err)
	}
	fmt.Println(payment.RedirectURL())
}

Send the customer to payment.RedirectURL(). When they finish, epoint calls your result URL. Verify it before trusting it:

callback, err := client.VerifyCallback(data, signature)
if err != nil {
	http.Error(w, "invalid", http.StatusBadRequest)
	return
}
if callback.OK() {
	fulfil(callback.OrderID, callback.Transaction)
}

Configuration

client := epoint.New("i000000001", "your-private-key",
	epoint.WithBaseURL("https://epoint.az"),
	epoint.WithLanguage(string(epoint.LanguageAZ)),
	epoint.WithCurrency(string(epoint.CurrencyAZN)),
	epoint.WithRedirectURLs("https://shop.example/thanks", "https://shop.example/failed"),
	epoint.WithHTTPClient(customClient),
)

Or read from the environment with epoint.FromEnv(), which uses EPOINT_PUBLIC_KEY, EPOINT_PRIVATE_KEY, EPOINT_BASE_URL, EPOINT_LANGUAGE, EPOINT_SUCCESS_REDIRECT_URL and EPOINT_FAILED_REDIRECT_URL. Language and currency are set on the client and can be overridden per call through the options argument. Pass nil for the options when you do not need any.

Testing against the sandbox

There is a local sandbox that behaves like the real gateway, so you can build and test without a merchant account or real money:

client := epoint.New("i000000001", "sandbox_private_key_0000000001",
	epoint.WithBaseURL("http://localhost:8181"))

See epoint-sandbox. Switching to production means changing the base URL and the keys, nothing else.

Responses

Most methods return (*Response, error). Known fields have accessors, anything else is read through Get, String, or the raw map:

status, err := client.GetStatus(ctx, "te0000000001")
status.Status()          // "success"
status.OK()              // true
status.String("rrn")     // bank reference number
status.Raw               // the full response map

A declined payment is not an error. GetStatus returns normally with a status of epoint.StatusFailed, which you read through OK(). GetInstallmentPlans returns a slice and ListWallets returns a map.

Enums

Every value the API uses has a typed constant. They come from the sandbox's own definitions, so they match what production sends. Each type is a string, so a plain string still converts.

client := epoint.New(publicKey, privateKey,
	epoint.WithLanguage(string(epoint.LanguageEN)),
	epoint.WithCurrency(string(epoint.CurrencyUSD)),
)

status, err := client.GetStatus(ctx, transaction)
if err == nil && epoint.Status(status.Status()).Settled() {
	fulfil(orderID)
}

Type	Values
Status	new, success, failed, error, returned, server_error
CardStatus	new, active, pending, rejected, expired, session_expired
InvoiceStatus	waiting_for_payment, paid, canceled
B2BStatus	PENDING, PROCESSING, SUCCESS, FAILED
OperationCode	001 card registration, 100 payment, 200 registration with payment
Language	az, en, ru
Currency	AZN, USD, EUR, RUB

Currency is not uniform across the API. Checkout takes all four, but split, pre-auth, refund, reverse, payout and wallet take AZN and nothing else. SupportedCurrencies and AZNOnly hold those two sets.

Status.Settled() reports whether the money moved and CardStatus.Usable() whether a card can be charged.

Methods

Group	Methods
Checkout	CreatePayment, CreatePaymentRequest, CreateAmexPayment, ChangePaymentSum
Status	GetStatus, GetCardStatus, GetBankTransfer
Split	CreateSplitPayment, SplitChargeSavedCard
Pre-auth	Reserve, Capture
Saved cards	RegisterCard, RegisterCardAndPay, ChargeSavedCard
Money back	Refund, Reverse
Installments	GetInstallmentPlans, PayByInstallment
Wallets	ListWallets, PayWithWallet
Apple Pay, Google Pay	CreateWidget
Invoices	CreateInvoice, UpdateInvoice, GetInvoice, ListInvoices, SendInvoiceSMS, SendInvoiceEmail
B2B	CreateBankTransfer, GetBankTransfer
Health	Heartbeat

Errors

Use errors.As to inspect what went wrong:

Type	Returned when
*GatewayError	epoint returned status: error. Has Code, Status, Message, Payload.
*TransportError	Network failure, or a non-JSON or 4xx/5xx response. Has StatusCode.
*SignatureError	A callback's signature did not match, or its data would not decode

var gwErr *epoint.GatewayError
if errors.As(err, &gwErr) {
	log.Printf("declined with code %s", gwErr.Code)
}

Signatures

Epoint signs with base64(sha1_raw(private_key + data + private_key)). The client builds and verifies these for you. The digest is the raw 20 bytes, not the hex string, which is where most hand-rolled integrations go wrong.

Not affiliated with Epoint

An independent client for developers integrating with epoint.az.

MIT licensed.