A SaaS founder in Kuala Lumpur invoices a client monthly for software access. She treats each invoice the same way her competitors do—but Malaysia's SST rules for recurring services differ sharply from how Singapore handles GST on subscriptions. One wrong choice compounds monthly, and by tax audit season, she's facing a six-figure exposure. Recurring revenue looks simple: charge monthly, invoice monthly, repeat. Tax compliance is where most platforms fail. Singapore and Malaysia have fundamentally different rules for subscription GST and SST, including reverse-charge obligations, invoice timing requirements, and what counts as a supply. Your invoicing tool must enforce the right rules for each market—most don't. Singapore: GST on supplies of services, timing rules, and the reverse-charge trap Singapore's GST applies to supplies of services made by a registered GST supplier. For a recurring subscription (software as a service, ongoing consulting, retainers, digital content), GST is due when the invoice is issued, not when payment arrives. The critical rule: invoice timing determines your GST liability month. If you invoice on the 1st of each month for service delivered over that month, your GST is due in that month's return. If you issue an invoice on the 30th for service ending the 31st, that GST applies to the following month's return. One day's difference shifts your cash-flow timing and can create unintended deferrals. Most businesses invoice on a fixed day (1st, 15th, or end of month). Your invoicing system must support that consistency and lock the invoice date to the service period. Backdating invoices is a red flag; IRAS (the Inland Revenue Authority of Singapore) treats it as evidence of manipulation. Reverse charge: when your subscription client is overseas If your customer is GST-registered outside Singapore (including Malaysia), the reverse charge mechanism applies. You do not charge GST on the invoice. Instead, the overseas customer self-accounts for GST in their own jurisdiction. This eliminates your GST liability on that transaction. But you must document this correctly: The invoice must state "No GST—reverse charge applies" or similar. You must hold a GST registration certificate or business registration proof of the customer's jurisdiction (Malaysia SST registration, for example). Your GST return must show the transaction as a zero-rated supply with reverse charge. Fail to document it, and IRAS will assess GST on the full amount. Your invoicing tool should include a field for the customer's tax registration number and a flag that triggers "reverse charge" language on the invoice. Malaysia: SST on services, the timing minefield, and MyInvois integration Malaysia's Service and Sales Tax (SST) applies to services and goods. For recurring services (hosting, software, subscriptions), SST is charged at 6% on the supply value. The trigger is the same as Singapore—the invoice date, not the payment date. However, Malaysia has an additional layer: MyInvois compliance. As of mid-2023, all invoices issued in Malaysia (regardless of customer location) must be submitted to the Inland Revenue Board's e-invoicing portal within a defined period. Your invoicing system must integrate with MyInvois or export data in the required format (XML, typically) to stay compliant. For a subscription business, this means each recurring invoice must be logged and transmitted to MyInvois. Miss the deadline or format the invoice wrong, and you face penalties ranging from RM1,000 to RM100,000 depending on severity and repetition. Invoice timing and deferral in Malaysia A common mistake: invoicing a 12-month retainer upfront. Under Malaysia's rules, if you invoice for 12 months of service on a single invoice, SST is due on the full amount immediately, even though you haven't delivered all the service yet. A better approach is to invoice monthly, deferring SST to the month service is actually rendered. If your contract requires upfront payment (common in SaaS), you still invoice and accrue SST as service is delivered. This creates a mismatch between cash received and SST liability—your accounting system must track deferred revenue alongside SST obligation. Most invoicing platforms don't separate the two. MyInvois requirements for recurring invoices MyInvois demands: Invoice number in sequence (no gaps or duplicates). Customer's business registration or identity number (if available). Itemized description of services (not just "subscription" or "retainer"). Submission within 24 hours of invoice issuance (strict deadline). XML or API submission; email or manual entry doesn't satisfy the requirement. For subscription businesses with hundreds of monthly invoices, manual submission is impossible. Your invoicing tool must automate MyInvois filing. Orin's billing system integrates MyInvois submission , eliminating the lag and error risk of manual export-and-upload. Cross-border recurring revenue: mixing Singapore and Malaysia customer