MyInvois Portal vs API Integration: Which e-Invoice Submission Method Fits Your Business?

MyInvois API or MyInvois Portal: The Short Answer

Use the MyInvois Portal if you issue a small number of invoices and have no system that can connect to LHDN; use the MyInvois API, either through your own integration or through accounting software that has it built in, if you issue invoices regularly, need consolidated or self-billed e-invoices, or want e-invoices to come straight from your sales records. For most Malaysian SMEs above a handful of invoices a week, API submission through their accounting software is the more sustainable choice because it removes double entry.

Both methods lead to the same result: an e-invoice validated by LHDN with a unique identifier number. The difference is how the data gets there, who keys it in, and how errors are caught. This guide compares the two routes using LHDN’s e-Invoice Guideline and the MyInvois SDK, and explains the practical trade-offs we see when helping Malaysian businesses choose.

How the MyInvois Portal Works

The MyInvois Portal is LHDN’s web application for taxpayers who cannot issue e-invoices through their own systems. LHDN’s guideline describes it as suited to businesses that need to issue e-invoices but do not have an API connection available. There are two ways to submit through it:

• Single submission: you fill in an online form with all the required fields for each e-invoice.
• Batch upload: you prepare multiple e-invoices in LHDN’s predefined Microsoft Excel spreadsheet and upload the file.

Once an e-invoice is validated, the portal can generate a PDF visual representation with a QR code, which your buyer can scan to check the e-invoice’s status on MyInvois.

Where the portal works well

• Very low invoice volumes, such as a consultant issuing a few invoices a month.
• Occasional self-billed e-invoices or one-off transactions that your normal system does not handle.
• A temporary fallback while an integration is being set up or tested.

Where it struggles

• Double entry. Each invoice is created in your accounting system and again in the portal, so mistakes and mismatches creep in.
• Batch preparation effort. Spreadsheets must match LHDN’s template exactly, and someone has to export, reformat and check them every time.
• No link back to your books. The unique identifier number and validation status have to be recorded against the original invoice manually.

How MyInvois API Integration Works

With the MyInvois API, your accounting or ERP system sends e-invoices to LHDN automatically and receives the validation result back. LHDN’s guideline describes the API as ideal for large taxpayers or businesses with substantial transaction volume, noting that it requires upfront investment in technology. There are three ways to connect:

1. Direct integration between your ERP or accounting system and the MyInvois System.
2. Peppol service providers, who connect to MyInvois on your behalf.
3. Non-Peppol technology providers, such as accounting software vendors and middleware platforms.

What the API requires

• Structured data: e-invoices are submitted in XML or JSON following the Universal Business Language (UBL) 2.1 data structure.
• A digital certificate: each submission carries a digital signature that verifies the issuer. Where a technology provider submits for you, the e-invoice is signed with the provider’s certificate.
• Taxpayer permissions: if an intermediary submits on your behalf, you grant it permission in MyInvois, and the intermediary can only act within those permissions.

The API submission flow, step by step

1. Your system authenticates with MyInvois and obtains an access token.
2. The invoice is converted into UBL 2.1 XML or JSON and digitally signed.
3. The document is submitted, and MyInvois returns a submission reference.
4. MyInvois runs structure and core field checks immediately, then signature, taxpayer, referenced-document and duplicate checks in the background.
5. Your system polls the submission status and receives either a valid result, with the unique identifier number and the details needed for the validation link, or an error response explaining what to fix.
6. Your system stores the result against the original invoice and embeds the QR code in the visual representation shared with the buyer.

The full requirements are in the LHDN e-Invoice guidelines, which also explain the validation statuses of Submitted, Valid, Invalid and Cancelled.

Technical limits to plan around

The MyInvois SDK integration practices and API documentation set out the operating rules developers must follow, including:

• Up to 100 e-invoices per submission, a maximum submission size of 5 MB and up to 300 KB per e-invoice.
• A recommended limit of 100 Submit Documents requests per minute per client ID, with lower limits for other calls such as cancellation and searches.
• Access tokens should be cached and reused for their lifetime rather than requested for every call.
• Status should be checked by polling the submission, and documents should not be resubmitted after a successful response, as this is flagged as a duplicate.
• The sandbox is for functional testing only, has lower rate limits and deletes data after up to three months.

None of this is difficult for an experienced developer, but it is ongoing work. LHDN updates the SDK and validation rules, so a custom integration needs someone to maintain it.

MyInvois Portal vs MyInvois API: Side-by-Side Comparison

Whichever route you choose, the compliance rules are identical. Validation happens in near real-time, each valid e-invoice receives an LHDN unique identifier number and validation link, and suppliers can cancel, or buyers can request rejection of, an e-invoice within 72 hours of validation. After 72 hours, corrections must be made through a credit note, debit note or refund note e-invoice.

Three Practical Options for Malaysian SMEs

In practice, the choice is rarely just portal or API. Most businesses we work with end up in one of three set-ups.

Option 1: Portal only

Suitable for very small volumes or businesses that are voluntarily adopting e-invoicing. Low cost, but heavy on manual work and only sensible while volumes stay low.

Option 2: Accounting software with built-in MyInvois API

Your accounting software handles the API connection, digital signing, retries and status updates. You issue invoices as usual, and they are submitted to LHDN from the same screen. For most Malaysian SMEs this offers the best balance of cost and control, because the vendor maintains the integration as LHDN changes its rules.

Option 3: Custom ERP integration or middleware

Larger businesses running Oracle NetSuite, a custom system or several platforms may integrate directly or through a Peppol or technology provider. This gives the most flexibility but needs proper design, testing and ownership. Our article on how NetSuite handles Malaysia e-invoicing compliance explains how this works in an ERP setting.

Using the MyInvois API Through AutoCount

AutoCount’s e-invoice solution is an example of Option 2. AutoCount says its AutoCount e-Invoice Platform (AIP) is built on LHDN’s official e-Invoice SDK and enables direct submission of e-invoices to MyInvois through the familiar AutoCount interface. According to AutoCount, the platform:

• Manages buyer details and TINs during onboarding.
• Updates MSIC codes and units of measure in line with LHDN requirements.
• Queues invoices and retries submissions during LHDN downtime until they are validated.
• Supports standard e-invoices from AutoCount Accounting and AutoCount Cloud Accounting, consolidated e-invoices for retail and F&B through POS, and self-billed e-invoices for cases such as payments to agents, dealers and distributors.

AutoCount Cloud Accounting lets you submit for e-invoice validation directly within the system, without maintaining servers. If you consolidate B2C sales, our guide to e-invoice consolidation rules SMEs often miss covers what to watch for.

How to Choose Your e-Invoice Submission Method

Work through these questions before deciding:

1. How many invoices do you issue each month? If the answer is more than you would happily retype, the portal will become a bottleneck.
2. Where are invoices created today? If they already come from an accounting, POS or ERP system, submitting from that system avoids duplicate records.
3. Do you need consolidated or self-billed e-invoices? These are much easier to generate from source transactions than to prepare by hand.
4. Who will maintain the connection? A custom integration needs an owner who tracks SDK and rule changes. Built-in software integration shifts that work to the vendor.
5. What happens when LHDN is unavailable? Check whether your method queues and retries automatically or depends on someone resubmitting.
6. Are you within scope? Under LHDN’s General Guideline version 4.8, taxpayers with annual turnover or revenue of less than RM3 million are exempt, subject to group rules, but may adopt e-invoicing voluntarily.

For the errors we see most often after go-live, read common e-invoicing mistakes Malaysian SMEs make.

Next Steps: Move from Manual Uploads to Automated Submission

If your team is retyping invoices into the MyInvois Portal or rebuilding Excel batches every week, that is usually the signal to move to API submission through your accounting system. Start by listing your invoice types, monthly volumes and the systems that create them, then check which of those can submit to MyInvois directly.

iDynamics implements and supports AutoCount for Malaysian businesses, including set-up of e-invoice submission. See how AutoCount Cloud Accounting with built-in e-invoice validation could replace manual uploads, or request a free consultation and demo with iDynamics to review your current e-invoice process.

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