How does GST 9% + OVR work for my Magento store?

GST in Singapore is now 9% (raised from 7% in two stages: 7% → 8% in Jan 2023, 8% → 9% in Jan 2024). Three scenarios:

• SG-registered seller — mandatory GST registration above S$1M turnover. Charge 9% on B2C, zero-rate exports. UEN + GST number visible on invoices.
• SG seller below S$1M — voluntary registration possible (good for input-tax claims). Otherwise no GST charged.
• Foreign seller (OVR) — Overseas Vendor Registration required if selling digital services + low-value goods (≤ S$400) into SG above S$100k turnover. Register with IRAS, charge 9% GST, file quarterly returns.

We rebuild Magento’s tax engine with these rules, validate UEN + GST numbers via IRAS API for B2B counterparties (zero-rate B2B exports), and wire MTD-equivalent reporting to Xero / QuickBooks SG.