The Coretax Administration System (CTAS) is the DGT's core tax administration system, which began rolling out in January 2025. It replaces and consolidates functions that used to be scattered across DJP Online, e-Faktur, e-Bupot, and other applications — into one portal with a single taxpayer profile.
Major changes you need to understand
- 16-digit National ID (NIK)/Tax ID (NPWP) as a single identity. Taxpayer profiles, including branches, are now consolidated. Make sure your NIK–NPWP data matching is already sorted out.
- The "taxpayer account" concept and digital power-of-attorney/PIC designation. A director or designated person (person in charge) accesses the system on behalf of the business entity through their own account. Manage this access carefully — who can issue invoices is an important internal control.
- Tax invoices are issued directly in Coretax (or via host-to-host integration for high-volume companies). Technical guidance is set out in, among others, PER-1/PJ/2025.
- Tax deposit. There's a deposit balance mechanism usable for paying various tax types — helping avoid late payments due to billing issues.
- Input tax crediting is stricter on timing. In line with MoF Reg. 81/2024, discipline around invoice issuance periods and crediting timing matters more — don't stockpile invoices to credit "later."
A healthy monthly workflow in the Coretax era
| WEEK | ACTIVITY |
|---|---|
| Week 1 | Reconcile last month's sales against output invoices issued in Coretax; issue any outstanding invoices. |
| Week 2 | Collect & validate input invoices from suppliers; match against purchase bookkeeping. |
| Week 3 | Calculate VAT payable/overpaid, Article 21, Unification Withholding Tax; prepare payment (use deposit balance if available). |
| Week 4 | File periodic returns before the deadline; archive the electronic receipt (BPE) and working papers. |
The most common mistakes
- Profile data not updated. An outdated address, business classification code, or PIC means important notifications don't arrive — and can complicate invoice validation.
- Treating an invoice as "issued" when it's still a draft. In Coretax, an invoice must be in approved/valid status. A draft invoice isn't valid as a basis for crediting by the counterparty.
- Delaying data entry until month-end. Server load and mass validation near deadlines risks the process getting stuck. Spread entries throughout the month.
- Not keeping independent archives. Even though the data lives in the DGT's system, keep an internal copy of invoices, returns, and BPE — a comparison document is invaluable when discrepancies arise.
- Uncontrolled access rights. An employee who's left but still has account access is a real risk. Review your list of proxies/PICs periodically.
Transition period & sanctions: in the early rollout, the DGT gave some leeway for delays caused by system issues. Don't rely on that as a habit — once the system stabilizes, standard administrative sanctions apply. The safe assumption: treat it as zero tolerance, and build a process that finishes ahead of the deadline.
Coretax readiness checklist for your business
- NIK–NPWP matching completed for all officers.
- PIC and access-role division formally established in writing.
- Invoice issuance SOP (who creates, who approves, when) documented.
- Customer & supplier master data (NPWP, address, email) valid.
- Monthly reconciliation schedule running — not just before deadlines.
If those five points are covered, most of the Coretax complaints business owners typically raise practically won't happen to you.
Disclaimer: This article was prepared as general information as of May 22, 2026 and does not constitute tax advice for any specific case. Tax regulations are subject to change. For guidance on your specific business situation, please consult the Sentary Consulting team or a registered tax consultant.