Payment Gateway API

Overview

SGT Payment Gateway API is a headless payment gateway for e-commerce platforms, mobile apps and SaaS products. One REST API accepts cards (Visa / Mastercard / Amex / local schemes), wallets, bank transfers and Buy-Now-Pay-Later — handles tokenisation, 3-D Secure 2.x challenges, smart-routing across multiple acquirers, and merchant settlement.

Built for developers: a single charge call, deterministic webhooks, idempotency keys on every request, OpenAPI-3 spec, SDKs in JavaScript / Python / Go / Java / PHP, a hosted-checkout fallback for low-effort integration, and a dashboard that gives finance teams reconciliation reports in two clicks. Designed for 99.99% uptime with multi-acquirer failover so a single bank outage never takes your checkout down.

One API · five rails — card, wallet, bank, BNPL, recurring — through the same endpoint
Smart-routing — automatic acquirer selection by BIN, cost, success-rate, region
3DS 2.x — built-in challenge flow, exemption logic, liability shift
Tokenisation — PAN never touches your servers, PCI scope reduced to SAQ-A

How It Works

API Console — your developer calls POST /v1/charges with amount, currency, source token and method. The gateway accepts in 18 ms median, returns a transaction object or a 3DS redirect URL. SDKs and a Postman collection make integration a few-hour job.
Transaction Flow — every charge passes through Auth → 3DS (if required) → Capture → Settle. Each stage emits webhooks; failures auto-retry with exponential back-off; the final state is always one of succeeded / failed / refunded.
Rails / Acquirers — the routing engine picks the best acquirer per transaction using BIN, live success-rate, scheme, region and cost. If acquirer-A drops, traffic spills to acquirer-B in under a second.
Merchant / Customer — customer sees a hosted or in-context checkout; merchant gets a real-time webhook, a daily payout report, and dashboards for refunds, disputes and reconciliation.

Features

Card vault & tokenisation — store cards once, charge forever, PCI scope at SAQ-A
3DS 2.x — frictionless and challenge flows, exemption engine, full liability shift
Multi-acquirer smart-routing — BIN-based, cost-based, success-rate-based, region-based
Recurring & subscriptions — schedule, retry, dunning, proration, MIT 3DS-cred-on-file
Refunds & partial refunds — same API, same idempotency model
Dispute & chargeback workflow — receive notice, upload evidence, track outcome
Webhooks & idempotency — at-least-once delivery, signed payloads, replay tool
Hosted checkout — drop-in iframe or hosted page for merchants who want zero front-end work
Reconciliation — daily settlement file (CSV / Parquet) matched to payout deposits

Use Cases

E-commerce platforms — single integration accepts every popular method in your region
SaaS subscriptions — recurring billing with dunning and 3DS-cred-on-file
Marketplaces — split payments to multiple sellers, escrow holds, payout schedules
Mobile apps — native SDKs for iOS / Android, Apple Pay / Google Pay tokens
Bill payment / utility platforms — bank-rail + wallet for low-fee acceptance
Cross-border merchant acceptance — multi-currency, dynamic-currency-conversion, localised methods

Specifications

API: REST / JSON, OpenAPI 3 spec, idempotency keys, signed webhooks (HMAC-SHA256)
SDKs: JavaScript, Python, Go, Java, PHP, Ruby; native iOS Swift and Android Kotlin
Methods: Visa, Mastercard, Amex, JCB, UnionPay, regional schemes; wallets; bank transfer (NPSB / RTGS / FPX / VA); BNPL
Latency: p50 18 ms, p99 64 ms gateway-side (excludes external scheme RTT)
Throughput: 5,000 TPS per region cluster, horizontal scaling
Compliance: PCI-DSS Level 1 service provider, 3DS 2.2, PSD2 SCA, regional regulator pre-certified
Uptime: 99.99% SLA, multi-region active-active, sub-second acquirer failover
Settlement: T+1 standard, T+0 fast-track per agreement, multi-currency payout