MyInvois Portal vs API: E-Invoicing for Custom Websites

1. What Is the MyInvois Portal and Who Is It For?

Quick Answer: The MyInvois Portal is LHDN’s own web platform for issuing, viewing, cancelling and rejecting e-invoices. You log in through MyTax, then complete a form for each e-invoice or upload a pre-set Excel sheet in batches. It is free, needs no software, and suits businesses whose own system cannot connect to LHDN.

LHDN’s e-Invoice Guideline (Version 4.8, 30 August 2026) lists two ways to send e-invoices for validation: the Portal and the Application Programming Interface (API). It pairs the Portal with businesses that have no API connection, and the API with high transaction volumes.

• Two ways to create. One form per e-invoice, or batch upload of LHDN’s Excel template.
• Near real-time validation. Each e-invoice gets an LHDN Unique Identifier Number, a validation time and a PDF copy with a QR code.
• A 72-hour window. Suppliers can cancel, and buyers can request rejection, within 72 hours. After that, corrections need a credit, debit or refund note.
• No charge. LHDN’s e-Invoice FAQs (updated 4 September 2026) say it is free of charge to all taxpayers.

2. Who Must Issue E-Invoices in Malaysia as at October 2026?

Quick Answer: As at October 2026, businesses with annual turnover below RM3 million are exempt, after the threshold rose from RM1 million on 1 September 2026. Businesses above RM3 million are in scope under the phased timeline. Those in the up-to-RM5 million phase have an interim relaxation period until 31 December 2027.

Check these dates before paying for any integration:

The phases come from LHDN’s e-Invoice implementation timeline page. The RM3 million change was announced by the Prime Minister on 30 August 2026, as reported by The Star. Two details matter:

• The exemption has limits. Guideline section 1.6.10 excludes you if a corporate shareholder, holding company or related company has turnover of at least RM3 million.
• The relaxation is temporary. Until 31 December 2027, phase 4 businesses may consolidate all transactions, even when a buyer asks for an individual e-invoice.

For the wider small-business picture, read our guide on what small businesses must do for e-invoice.

3. MyInvois Portal vs API: What Is the Difference?

Quick Answer: Both send the same e-invoice to the same LHDN system for validation. The MyInvois Portal is manual and free. The API is automatic: your website builds the e-invoice in UBL 2.1 JSON or XML, signs it with an organisation digital certificate, and submits it the moment an order is paid. That saves staff time but costs development.

How the two routes compare for a business with its own website or web app:

The MyInvois SDK FAQ states that API submission needs an organisation digital certificate, from a certification authority on MCMC’s list of digital signature licensees.

There is a middle road too: if your website already pushes orders into accounting software, that software may submit e-invoices for you. Our website to SQL Accounting and AutoCount integration guide covers that route.

4. Is the MyInvois Portal Enough for an Online Store?

Quick Answer: Often, yes, for now. Most consumer orders can go into one consolidated e-invoice per month, submitted within seven calendar days of month end, and that is a single Portal entry. The MyInvois Portal stops being practical when you get many requests for individual e-invoices, or many orders above RM10,000.

Under LHDN’s e-Invoice Specific Guideline (Version 4.9, 7 September 2026), consumer sales where the buyer does not ask for an e-invoice can be consolidated monthly, while single transactions above RM10,000 need their own from 1 January 2026. Our guide to consolidated e-invoices for online sales explains the monthly routine.

So what matters is the number of orders needing their own e-invoice, not total orders. Manual work grows fast:

Excel batch upload cuts the typing, but someone still exports orders, cleans data and fixes rejected rows. The tipping point usually comes when e-invoicing needs a part-time person. And because phase 4 businesses may consolidate everything until 31 December 2027, the real pressure for many SMEs starts in 2028.

5. How Does MyInvois API Integration Work With a Custom Website?

Quick Answer: Your developer registers your website as an ERP system in the MyInvois Portal to get a client ID and secret, installs your organisation digital certificate, builds e-invoices in UBL 2.1 format, tests them in LHDN’s sandbox, then switches to live. Each paid order is submitted, validated and stored with its LHDN identifier.

How to connect a custom website to the MyInvois API

A typical build, following the official MyInvois SDK and LHDN’s guideline:

1. Register the system. In the Portal, use “View and Register ERP” to self-provision a client ID and client secret.
2. Get the certificate. Buy an organisation digital certificate from an MCMC-licensed authority, in your company’s name, not the developer’s.
3. Collect the right data. Let checkout or the buyer’s account capture TIN, registration number and address when an individual e-invoice is wanted.
4. Build the document. Map each order to the UBL 2.1 structure in JSON or XML, covering the 55 required fields, and sign it.
5. Test in the sandbox. Use the pre-production environment, with its own client ID and secret, until submissions validate cleanly.
6. Go live and store results. Save the Unique Identifier Number, validation time and QR link against each order, and show the buyer their copy.
7. Handle the exceptions. Build 72-hour cancellation, credit and refund notes, and a retry queue for LHDN downtime.

Step 3 is where websites usually fall short. A simple e-invoice request form on your website collects buyer details without slowing everyday customers. Refunds need a flow too; see how e-invoice credit notes work for online refunds.

Shops on a platform can compare plug-in routes for linking a WooCommerce store to MyInvois and Shopify e-invoice apps. Bespoke systems, such as custom web applications, normally connect directly.

6. What Are the MyInvois API Limits Your Developer Must Plan For?

Quick Answer: The MyInvois SDK sets a maximum of 100 e-invoices and 5 MB per submission, 300 KB per e-invoice, and recommends about 100 requests per minute per client ID. Access tokens last 60 minutes, so a website should reuse them rather than log in for every order.

These limits rarely trouble an SME site day to day. They bite on sale days, at month end, and when code logs in again for every order.

The submission figures are on the SDK’s Submit Documents API page. LHDN’s FAQs add that if its system is down, suppliers have 72 hours to issue the e-invoice once it returns. For budgets, see our system integration cost guide.

7. Which Website Situations Point to the Portal or the API?

Quick Answer: Lead-generation sites that invoice offline, and small consumer shops, usually stay on the MyInvois Portal. Subscription sites, B2B ordering portals and sites with frequent orders above RM10,000 usually justify the API, because each sale needs its own e-invoice and manual entry never ends.

• Lead-generation or brochure site. Enquiries come in; invoices are raised later. The Portal or your accounting software is enough.
• Small consumer shop on a custom build. Consolidate monthly and handle the odd buyer request by hand.
• Subscription or membership site. Renewals repeat monthly, so automation pays back fast. See e-invoices for subscription and membership websites.
• B2B ordering or quotation portal. Corporate buyers expect a validated e-invoice per order, which points to the API.
• Sales above RM10,000. Each needs its own e-invoice. A few a month is fine by hand; dozens are not.

Purchases count too. Self-billed e-invoices for foreign ad platforms and creators are often issued by hand, even by businesses that automate sales. Read about self-billed e-invoices for Facebook and Google Ads payments and e-invoices for influencer and freelancer payments.

8. Can You Claim Tax Deductions or Grants for an E-Invoice Build?

Quick Answer: Possibly. Malaysia has offered MSMEs a tax deduction linked to certain e-invoice implementation costs, and some digitalisation grants cover custom software work. The rules, caps and deadlines differ by scheme and change often, so check the current terms with a licensed tax agent before you sign a development quote.

Our post on the e-invoice integration tax deduction explains which costs may qualify, and our custom software development grants guide covers schemes that may part-fund the build.

On data: LHDN’s FAQs say the Personal Data Protection Act 2010 does not apply to personal data processed for e-invoices sent to the Director General. That covers the e-invoice only. Your tracking pixels and lead forms still fall under PDPA, as we explain in Meta Conversions API and PDPA.

9. Portal or API Checklist: What to Confirm Before You Decide

Quick Answer: Confirm your scope and relaxation date, count orders needing individual e-invoices, and check whether your accounting software already submits to MyInvois. Only then compare a build quote against the monthly staff hours the Portal would cost.

• Scope. Is your turnover, or your group’s, at least RM3 million?
• Deadline. Which phase are you in, and when does your relaxation end?
• Volume. How many orders a month need their own e-invoice, including those above RM10,000?
• Existing tools. Does your accounting or POS software already connect to MyInvois?
• Ownership. Are the client ID, secret and certificate in the company’s name?
• Upkeep. Who handles cancellations, downtime and LHDN’s SDK updates?

Worked example. A Klang Valley furniture retailer with RM4 million turnover gets about 40 individual e-invoice requests a month, plus five orders above RM10,000. At roughly four minutes each, that is about three staff hours a month in the MyInvois Portal, which is reasonable. If it opens a B2B trade portal with 400 orders a month, the same maths reaches about 27 hours, and the API becomes worth pricing.

10. Conclusion

Both routes produce the same validated e-invoice. The Portal is free and fine for low volumes, especially while the relaxation period lasts. The API suits websites with steady individual e-invoices, B2B buyers or high-ticket orders, and needs a certificate, sandbox testing and proper error handling. As at October 2026, the RM3 million exemption has taken many SMEs out of scope, so confirm your position with a licensed tax agent first.

11. Frequently Asked Questions

1. Is the MyInvois Portal free to use?

Yes. LHDN’s e-Invoice FAQs say the MyInvois Portal is free of charge to all taxpayers. You log in through MyTax and create e-invoices one by one or by Excel batch upload. The only cost is staff time.

2. Do I need a digital certificate to use the MyInvois Portal?

No, not for normal Portal entry. The MyInvois SDK FAQ says an organisation digital certificate is required for API submission. Buy it from a certification authority on MCMC’s licensee list, in the company’s name.

3. Can a custom website connect directly to LHDN’s MyInvois system?

Yes. LHDN allows direct integration with the MyInvois API, or a connection through Peppol or non-Peppol technology providers. The website is registered as an ERP system to get a client ID and secret, then tested in the sandbox before going live.

4. Is my business exempt from e-invoicing in 2026?

From 1 September 2026, businesses with annual turnover below RM3 million are exempt under LHDN’s e-Invoice Guideline Version 4.8, unless a corporate shareholder, holding or related company reaches RM3 million. Confirm your position with a licensed tax agent.

5. When should a website switch from the MyInvois Portal to the API?

Switch when manual entry becomes a recurring job: many individual e-invoice requests, regular orders above RM10,000, subscriptions or a B2B ordering portal. With the phase 4 relaxation ending on 31 December 2027, many SMEs plan the switch during 2027.