Go SDK

import stampmitra "github.com/Bani-Global-Industries-LLP/stampmitra-developer-go"

client, err := stampmitra.NewClient("") // empty = read STAMPMITRA_API_KEY
if err != nil { log.Fatal(err) }
pan, err := client.Verify.PAN(context.Background(), &stampmitra.PANVerifyParams{PAN: "ABCDE1234F", Name: "Rahul Kumar"})
if err != nil { log.Fatal(err) }
fmt.Println(pan.Valid, pan.NameMatchResult, pan.ReferenceID)

client, err := stampmitra.NewClient(key,
    stampmitra.WithBaseURL("https://api-b2b.stampmitra.in"),
    stampmitra.WithTimeout(30*time.Second),            // per attempt
    stampmitra.WithMaxRetries(2),
    stampmitra.WithBackoff(500*time.Millisecond, 8*time.Second),
    stampmitra.WithHTTPClient(httpClient),             // redirects are still never followed
    stampmitra.WithDefaultHeader("X-Trace", "abc"),
    stampmitra.WithAppInfo(stampmitra.AppInfo{Name: "my-app", Version: "1.0.0"}),
    stampmitra.WithLogger(slog.Default()),
    stampmitra.WithValidateInput(true),
    stampmitra.WithAllowCustomKey(),
)

// Every method takes a context.Context first and per-call options last:
// WithRequestTimeout, WithRequestMaxRetries, WithIdempotencyKey, WithRequestHeader, WithRawResponse

ctx := context.Background()

// Verification (every call, including valid=false results, is billed)
pan, err := client.Verify.PAN(ctx, &stampmitra.PANVerifyParams{PAN: "ABCDE1234F", Name: "Rahul Kumar"})
gst, err := client.Verify.GSTIN(ctx, &stampmitra.GSTINVerifyParams{GSTIN: "27ABCDE1234F1Z5"})
rc, err := client.Verify.RC(ctx, &stampmitra.RCVerifyParams{VehicleNumber: "MH12AB1234"})
voter, err := client.Verify.VoterID(ctx, &stampmitra.VoterIDVerifyParams{VoterID: "ABC1234567"})
dl, err := client.Verify.DrivingLicense(ctx, &stampmitra.DrivingLicenseVerifyParams{DLNumber: "MH1420110012345", DOB: "1990-01-31"}) // IP-allowlisted key
pp, err := client.Verify.Passport(ctx, &stampmitra.PassportVerifyParams{FileNumber: "PA1079341954215", DOB: "1990-01-31"})        // IP-allowlisted key
cin, err := client.Verify.CIN(ctx, &stampmitra.CINVerifyParams{CIN: "U74999DL2015PTC284009"})
udyam, err := client.Verify.Udyam(ctx, &stampmitra.UdyamVerifyParams{UdyamNumber: "UDYAM-MH-12-1234567"})
gstins, err := client.Verify.PANToGSTIN(ctx, &stampmitra.PANToGSTINParams{PAN: "ABCDE1234F"})
udyams, err := client.Verify.PANToUdyam(ctx, &stampmitra.PANToUdyamParams{PAN: "ABCDE1234F"})
bank, err := client.Verify.BankAccount(ctx, &stampmitra.BankAccountVerifyParams{AccountNumber: "000123456789", IFSC: "ICIC0001234", Name: "Rahul Kumar"})

// Services and e-Stamp reference data
services, err := client.Services.List(ctx)
service, err := client.Services.Get(ctx, "estamp.instrument.rent_agreement")
schema, err := client.Estamp.GetSchema(ctx, "estamp.instrument.rent_agreement")
states, err := client.Estamp.ListStates(ctx)
instruments, err := client.Estamp.ListInstruments(ctx, "MH")
articles, err := client.Estamp.ListArticles(ctx, "rent_agreement")
duty, err := client.Estamp.CalculateDuty(ctx, &stampmitra.EstampDutyParams{StateCode: "MH", ArticleCode: "5", StampDutyAmount: 500})
parties, err := client.Estamp.AddParties(ctx, "ord_ext_123", &stampmitra.EstampPartiesParams{CustomerName: "A", PartyName: "B"})

// Orders and payments: orders are addressed by YOUR externalOrderId
order, err := client.Orders.Create(ctx, &stampmitra.CreateOrderParams{
    ExternalOrderID: "ord_ext_123", ExternalCustomerID: "cust_ext_456", ServiceCode: "estamp.instrument.rent_agreement",
}, stampmitra.WithIdempotencyKey("create-ord_ext_123"))
detail, err := client.Orders.Get(ctx, order.ExternalOrderID)
status, err := client.Orders.GetStatus(ctx, order.ExternalOrderID)
payment, err := client.Orders.GetPayment(ctx, order.ExternalOrderID)
docs, err := client.Orders.ListDocuments(ctx, order.ExternalOrderID)
link, err := client.Orders.GetDocumentDownload(ctx, order.ExternalOrderID, "doc_1") // link.DownloadURL is short-lived
intent, err := client.Payments.Intents.Create(ctx, &stampmitra.CreatePaymentIntentParams{ExternalOrderID: "ord_ext_123", AmountMinor: 50000, Currency: "INR", PaymentConnectionID: "pc_1"})
intent, err = client.Payments.Intents.Get(ctx, intent.ID)

// Usage, logs, webhook deliveries
usage, err := client.Usage.Summary(ctx)
page, err := client.Logs.List(ctx, &stampmitra.LogsListParams{Service: "pan.verify", Status: "success", Limit: 50})
events, err := client.Webhooks.Events.List(ctx, &stampmitra.WebhookEventsListParams{Limit: 20})
replay, err := client.Webhooks.Events.Replay(ctx, "evt_1")

// Raw HTTP metadata
var raw stampmitra.Response
st, err := client.Orders.GetStatus(ctx, "ord_ext_123", stampmitra.WithRawResponse(&raw))
fmt.Println(st != nil, err == nil, raw.StatusCode, raw.RequestID, raw.Attempts)

it := client.Logs.ListAll(&stampmitra.LogsListParams{Service: "pan.verify", Limit: 100})
for it.Next(ctx) {
    entry := it.Log()
    fmt.Println(entry.ID, entry.CreatedAt)
}
if err := it.Err(); err != nil {
    log.Fatal(err)
}

page, err := client.Logs.List(ctx, &stampmitra.LogsListParams{Limit: 50}) // page.Items, page.NextCursor

_, err := client.Verify.GSTIN(ctx, &stampmitra.GSTINVerifyParams{GSTIN: "27ABCDE1234F1Z5"})
var apiErr *stampmitra.APIError
switch {
case err == nil:
    // success
case errors.As(err, &apiErr) && stampmitra.IsRateLimit(err):
    log.Println("rate limited; retry after", apiErr.RetryAfter) // zero when the API sent no Retry-After
case errors.As(err, &apiErr):
    log.Printf("%d %s (request %s): %s", apiErr.Status, apiErr.Code, apiErr.RequestID, apiErr.Message)
case stampmitra.IsValidation(err):
    log.Println("invalid input, nothing was sent:", err)
default:
    log.Println("request failed:", err)
}

// body: raw bytes from io.ReadAll(r.Body); do not decode and re-encode
ev, err := stampmitra.ConstructEventFromHeaders(body, r.Header, secret)
if err != nil {
    var sigErr *stampmitra.SignatureVerificationError
    if errors.As(err, &sigErr) {
        log.Println("rejected:", sigErr.Reason)
    }
    return
}
switch e := ev.(type) {
case *stampmitra.OrderDocumentReadyEvent:
    log.Println("document ready for", e.CoreOrderID, e.ID)
case *stampmitra.UnknownEvent:
    log.Println("unrecognised event", e.RawType)
}