If you're selling in Malaysia, you already know SST (Sales and Service Tax) is mandatory for most goods and services. What trips up most small businesses is the second part: you need your buyer's SST registration number—or proof they're exempt—before you can issue a valid invoice under MyInvois. WhatsApp is the fastest way to ask. Your CRM is where you validate before you invoice. Get the flow wrong and you'll either invoice without a match (compliance risk, audit pain) or delay every transaction until you chase down a ten-digit number. This playbook walks you through the right sequence. Why tax ID matching matters in Malaysia MyInvois, the Malaysian e-invoicing system, requires: Buyer's SST registration number if they're SST-registered (16 digits, format: [10-digit ID]-[4-digit check]). Exemption code if they're exempt (government bodies, non-profits, small traders below the RM500k threshold). A match between what you invoice and what the buyer can see in the Royal Malaysian Customs Department database (for registered businesses). Mismatches trigger validation failures and delays. If you invoice without collecting this upfront, you hit one of two problems: You submit a MyInvois invoice with a blank or wrong buyer tax ID. The system rejects it or accepts it but flags it. The buyer can't match it to their records. Your accounts team then has to issue a credit note and re-invoice—two extra documents, two extra days. You hold the invoice in draft, waiting for the buyer to reply to an email or call. Weeks pass. Your cash flow stalls. The buyer forgets. You follow up three times. The goal: collect the buyer's tax ID or exemption proof in the same conversation where you agree the sale. Before you generate the invoice. Before MyInvois. Collect SST ID over WhatsApp in the sales conversation WhatsApp is where Malaysian buyers already are. Use it to ask before the deal closes. The template message (after you've agreed the scope and price): "Thanks for confirming. Before I issue the invoice, I'll need your SST registration number (16 digits) or confirmation if you're exempt. Can you share that now? If you're not sure, check with your accountant or look it up on the Customs website." Send this before you hand over to invoicing. If they're a repeat buyer, store their tax ID in your CRM contact record on the first sale and reuse it. If it's a new buyer: They reply with the number. You note it. Move to invoicing. They reply "we're exempt." Ask for the exemption category (e.g., "government body", "non-profit", "small trader"). Note that instead. They don't know. Tell them: "Ask your accountant or check the Customs portal at www.myx.customs.gov.my. I'll wait." Set a follow-up in your CRM for 24 hours. Don't draft the invoice yet. They say "we're a small business, under RM500k, we don't need SST." Confirm: "Great, so you're exempt. I'll mark you as exempt on the invoice. Is that right?" (Get written confirmation so you have a record.) This upfront friction—thirty seconds of conversation—saves a week of back-and-forth later. Store and validate in your CRM before invoicing Once the buyer gives you their tax ID or exemption status, it needs to live in your CRM contact or company record. This is where a CRM with buyer data fields saves you. You're not just storing a phone number; you're storing tax compliance metadata. Add these fields to your buyer record: SST Registration Number (text, 16 digits) SST Status (dropdown: Registered / Exempt) Exemption Category (if exempt: Government, Non-profit, Small Trader, Other) Tax ID Verified Date (auto-timestamp when you confirmed it) Tax ID Verified By (which team member confirmed it) Before you issue an invoice, your invoicing workflow should enforce a rule: "Do not proceed if SST Status is blank." This stops invoices from going out incomplete. You can set this up as a simple automation in your CRM: if you try to create an invoice for a contact with no SST Status, the system flags it or blocks it. Orin's no-code automations let you build this without coding. Validate the number before MyInvois submission If the buyer gave you an SST number, validate it before you invoice. The Royal Malaysian Customs Department publishes a live registry. You can: Check manually: Visit myx.customs.gov.my and search the registration number. Takes two minutes. Do this for high-value invoices or new buyers. Ask the buyer to confirm: "Is [number] correct? I'm checking it in our records now." If they say yes, you've got written confirmation of what they gave you. Use an API (if your CRM supports it): Some accounting platforms in Malaysia have started integrating with the Customs registry. If yours does, use it. If not, manual checks are fine for most small businesses. The worst-case scenario: the buyer gives you a number that doesn't exist in the registry, or it's registered to a different entity. Ask them to double-check before you invoice. This is their problem to solve, not yours. You're just validating what