Quickstart

Get an access token

Every call needs a bearer token first. TokenManager fetches and caches it for you — concurrent callers during a refresh share one in-flight request instead of each firing their own.

tm := &snap.TokenManager{
	BaseURL:   "https://partner.example.com",
	ClientKey: clientKey,
	Signer:    rsaPrivateKey, // crypto.Signer, e.g. from snap.ParseRSAPrivateKeyPEM
}

accessToken, err := tm.AccessTokenB2B(ctx)
if err != nil {
	// handle error
}

See Authentication for B2B2C and token caching details.

Build a signed header

HeaderBuilder assembles the mandatory SNAP header set — X-SIGNATURE, X-TIMESTAMP, X-PARTNER-ID, and the rest — and signs the request for you. Pick exactly one of ClientSecret (symmetric/HMAC) or Signer (asymmetric/RSA), matching what you agreed with your partner at registration.

hb := snap.HeaderBuilder{
	Method:       http.MethodPost,
	EndpointURL:  "https://partner.example.com/v1.0/balance-inquiry",
	AccessToken:  accessToken,
	ClientKey:    clientKey,
	PartnerID:    partnerID,
	ExternalID:   externalID,
	ChannelID:    channelID,
	Symmetric:    true,
	ClientSecret: clientSecret,
}

See Headers & Signing for every field and what happens when one is missing.

Call an endpoint

Every domain package uses the same call shape: func Endpoint(ctx, *snap.Transport, snap.HeaderBuilder, Request) (Response, error).

transport := &snap.Transport{}

resp, err := balanceinfo.BalanceInquiry(ctx, transport, hb, balanceinfo.BalanceInquiryRequest{
	PartnerReferenceNo: "2020102900000000000001",
	AccountNo:          "1234567890",
})
if err != nil {
	// errors.Is(err, snap.ErrBadRequest), snap.ErrUnauthorized, etc. —
	// one sentinel per SNAP response-code HTTP-status class. See
	// /concepts/errors.
}

You don’t set hb.Body yourself — the calling function marshals the typed request and sets it, so the same bytes are used for both signing and the wire request.

Handle inbound notifications

Some flows (bulk cash-in, QR/MPM payments, direct debit, BI-FAST, RTGS, SKNBI) deliver their result as an inbound HTTP call to your service instead of a synchronous response. Verify every inbound request with snap.ServerVerifier before trusting its body — see Verifying inbound requests. Skip this step if you’re only calling read/inquiry endpoints.