Indonesia — Coretax DJP, e-Faktur, e-Bupot Unifikasi Skill v1.0

This skill is the platform manual for the Indonesian tax administration system. It explains how the buttons work and where the filings live. The substantive tax content (rates, base, deductions) is in the per-tax skills (indonesia-vat, id-payroll-pph21, etc.).

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Section 1 — Quick reference

Field	Value
Country	Indonesia (Republik Indonesia)
Platform	Coretax DJP (Sistem Inti Administrasi Perpajakan / SIAP)
Operator	Direktorat Jenderal Pajak (DJP), Kementerian Keuangan
Go-live	1 January 2025
Replaces	DJP Online e-Filing (2025+), desktop e-Faktur, separate e-Bupot apps, e-Registration, several legacy portals
Primary URL	coretaxdjp.pajak.go.id
Legacy URL still live	pajak.go.id / djponline.pajak.go.id (residual tax-year 2024 work)
Mobile app	"Coretax DJP" — Play Store and App Store (individual taxpayers)
Coretax Form	Offline preparation form for SPT 1770 — broadly available February 2026
Currency	IDR (Indonesian Rupiah)
NPWP format	16-digit (NIK-as-NPWP) for Indonesians since 1 July 2024; 15-digit padded to 16 for entities / foreigners
Tax invoice	Faktur Pajak via Coretax e-Faktur from 1 Jan 2025
NSFP	Nomor Seri Faktur Pajak — invoice serial, requested in Coretax
Unified withholding	SPT Masa PPh Unifikasi (PPh 23/26/4(2)/15)
Filing channels	Coretax web, Coretax Mobile, Coretax Form upload, PJAP host-to-host
Contributor	Open Accountants Community
Validated by	Pending — Konsultan Pajak sign-off required
Skill version	1.0

Conservative defaults

Ambiguity	Default
Coretax is unreachable at deadline	Document the attempt (screenshot, ticket number, timestamp), file as soon as access is restored, attach proof of attempted filing to the workpaper
Doubt over whether to file on Coretax vs DJP Online	Tax period on or after January 2025 → Coretax. Tax period December 2024 or earlier → DJP Online unless DJP has published a specific migration instruction for that form
NSFP request rejected or pending	Do not back-date a Faktur Pajak; issue once NSFP is granted; record the delay
16-digit vs 15-digit NPWP unclear	Indonesian individual → use NIK as 16-digit NPWP; foreign national → use existing 15-digit NPWP padded with leading "0" to 16 digits inside Coretax
Withholding category unclear between PPh 23 / 4(2)	Hold the filing; do not guess across PPh categories — the e-Bupot Unifikasi form requires the correct article designation
Coretax UI behaviour appears to differ from this skill	Trust the live UI and DJP help text. Mark "TBC" in the workpaper and update this skill

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Section 2 — Required inputs and refusal catalogue

Required inputs

Minimum viable — Coretax account credentials (or DJP-issued activation letter with PIN); NPWP (16-digit for Indonesian individuals, 15-digit for foreigners / legacy); tax period and year; the underlying tax computation from a sister skill (indonesia-vat, id-payroll-pph21, etc.).

Recommended — Faktur Pajak or withholding ledger in CSV/Excel for bulk import; counterparty NPWPs pre-validated against DJP; confirmed NSFP balance.

Ideal — PJAP host-to-host connection for high-volume taxpayers; valid digital certificate (sertifikat elektronik) renewed within the last 24 months.

Refusal if minimum missing — SOFT WARN. Without an activated Coretax profile, no filing can be lodged. Without a sister-skill tax computation, this platform skill cannot produce a return on its own.

Refusal catalogue

R-CT-1 — Tax content out of scope. This skill is the Coretax platform manual. PPN classification, PPh 21 bands, corporate income tax computations, and planning are handled by indonesia-vat, id-payroll-pph21, or the relevant income-tax skill.

R-CT-2 — Foreign-nationals' NPWP. WNA onboarding differs from the NIK-as-NPWP route. Foreigners currently use a 15-digit NPWP padded to 16 in Coretax — confirm the current DJP flow before activation. TBC — a dedicated foreign-taxpayer ID has been signalled.

R-CT-3 — Pre-2025 amendments via Coretax. Pembetulan for a tax period on or before December 2024 generally routes through DJP Online, not Coretax. Confirm the channel before submitting unless DJP has published a specific migration instruction.

R-CT-4 — Host-to-host / PJAP integration. Building or debugging a PJAP integration is engineering scope. Out of skill — escalate.

R-CT-5 — System outage on the deadline. Do NOT self-declare a Force Majeure waiver. DJP issues a Pengumuman when it grants relief. Reviewer must check pajak.go.id announcements before relying on any deemed extension.

R-CT-6 — Confidential digital certificate operations. Generating or renewing a taxpayer's sertifikat digital requires the taxpayer's own credentials — the skill walks through steps; it does not act on credentials.

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Section 3 — Coretax DJP overview

Coretax DJP is the Indonesian tax administration's unified back-office and taxpayer-facing platform, built under the Pembaruan Sistem Inti Administrasi Perpajakan (PSIAP) project. It went live 1 January 2025 and consolidates services that previously lived across multiple legacy DJP portals.

3.1 What Coretax replaces

Legacy service	Coretax replacement
DJP Online e-Filing (web SPT submission)	Coretax web portal — SPT module
Desktop e-Faktur (Java client)	Coretax e-Faktur (browser-based)
e-Bupot 23/26 web app	Coretax e-Bupot Unifikasi
e-Bupot 4(2) and PPh 15 separate apps	Same — folded into e-Bupot Unifikasi
e-Bupot 21/26 (employment)	Coretax e-Bupot 21/26 (separate monthly form, on Coretax)
e-Registration	Coretax registration module
e-Objection / e-Appeal	Coretax dispute module
e-Billing (kode billing)	Coretax payment module — still issues 15-digit ID Billing
e-SKD (residence certificates)	Coretax DTP / e-SKD module
KSWP (taxpayer status)	Coretax taxpayer-status service

3.2 What Coretax does NOT replace

Tax payment settlement still happens at a bank, BPD, Pos Indonesia, marketplace, or fintech accepting Kode Billing. Customs (Bea Cukai) PIB / PEB stays in INSW / CEISA. BPJS is a separate authority. Pre-2025 audit case files remain on legacy systems.

3.3 Coretax modules at a glance

Module	Purpose
Profil Wajib Pajak	Taxpayer profile, NPWP/NIK, KLU, address, PIC
Layanan	Service requests (PKP confirmation, NSFP, certificate, residence)
e-Faktur	Faktur Pajak issuance, NSFP balance, replacement & cancellation
e-Bupot Unifikasi	PPh 23/26/4(2)/15 slips + monthly SPT Masa Unifikasi
e-Bupot 21/26	Employment withholding monthly form
SPT Tahunan	1770 / 1770S / 1770SS (individuals); 1771 (corporates)
Pembayaran	Kode Billing, payment history
Restitusi	Refund applications
Sengketa	Objection (Keberatan) and appeal

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Section 4 — Account activation and NIK-as-NPWP

4.1 NIK-as-NPWP — 16-digit format

Under PMK-112/PMK.03/2022 (later operationalised through PER-04/PJ/2020 and amendments) the DJP unified the NIK (Nomor Induk Kependudukan — 16-digit national ID number) with the NPWP for Indonesian individual taxpayers. As of 1 July 2024 the 16-digit identifier is the only valid NPWP format for Indonesian citizens in all DJP services — Coretax enforces this.

Taxpayer category	NPWP format inside Coretax
Indonesian individual (WNI)	16-digit NIK = NPWP
Foreign individual (WNA)	15-digit legacy NPWP, padded with leading "0" to 16 digits at display time (TBC — DJP has signalled a dedicated 16-digit foreign-taxpayer identifier; confirm current state)
Indonesian entity (Badan)	15-digit NPWP padded to 16 digits with leading "0" inside Coretax
Government instrumentality	15-digit padded to 16
Branch (Cabang)	Parent 15-digit + 3-digit branch suffix → Coretax displays the consolidated identifier

4.2 Activation flow — first login

Order matters: Coretax will not allow NSFP requests, Faktur Pajak issuance, or return signing without an activated profile and valid digital certificate.

1. Visit coretaxdjp.pajak.go.id (confirm URL against the current DJP announcement).
2. Username — NIK / 16-digit NPWP for individuals; 15-digit padded to 16 for entities.
3. Reset password via "Lupa Kata Sandi" using the email/phone on file at DJP.
4. Verify email and phone — required before any service request.
5. Set Passphrase Sertifikat Digital — required every time a return is signed.
6. Confirm KLU (business activity code) and address — mismatches block NSFP requests.
7. Add PIC (Person in Charge) — at least one required for entities; each PIC has own login and signing role.
8. For PKPs: request or migrate the digital certificate (sertifikat elektronik) via the Layanan menu.

4.3 Sub-user / impersonation

Entities grant role-based access — typical roles are Penanggung Jawab (signing officer), Karyawan (operator), Konsultan Pajak (external agent). External tax agents act under their own NPWP via the Wakil Wajib Pajak flow.

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Section 5 — e-Faktur inside Coretax

The desktop e-Faktur Java client has been retired. All Faktur Pajak issuance from 1 January 2025 is browser-based inside Coretax. The legal substance of the Faktur Pajak (deadlines, 11% rate, exempt categories) is unchanged and lives in indonesia-vat. This section covers platform mechanics only.

5.1 NSFP — Nomor Seri Faktur Pajak

Every Faktur Pajak must carry a serial number issued by DJP. Coretax centralises NSFP request and consumption.

Step	Coretax action
1	Navigate to e-Faktur → Permintaan NSFP
2	Enter requested quantity. Coretax benchmarks against historical issuance and may auto-approve or queue
3	Sign the request with the digital certificate passphrase
4	DJP responds with a serial range (e.g., 0100002500000001–0100002500001000); positions 3-4 carry the year
5	Allocated NSFPs sit in the taxpayer's balance; each issued Faktur consumes one
6	Unused NSFPs must be returned via Pengembalian NSFP by 31 March of the following year

Practical timing. Peak windows queue NSFP requests for hours or days — do not wait until the Faktur is due.

5.2 Issuing a Faktur Pajak

1. e-Faktur → Buat Faktur Keluaran.
2. Pick the Kode Transaksi — 01 standard B2B, 04 special DPP, 07 zero-rated export of services, 08 exempt, etc.
3. Enter the counterparty NPWP — Coretax validates against the DJP master file in real time.
4. Enter DPP and PPN. Coretax computes PPN; override requires a flagged reason code.
5. Save — Coretax assigns the next NSFP from the pool.
6. Sign with the digital certificate passphrase. Coretax issues the QR-coded PDF.

5.3 QR code, replacement, cancellation

Each finalised Faktur Pajak carries a QR code linking to pajak.go.id verification. Faktur that fail QR verification are not creditable.

Scenario	Coretax action
Faktur Pengganti (replacement)	New Faktur with same period referencing original; code's first digit changes to 1 (011 instead of 010)
Faktur Dibatalkan (cancellation)	Use Pembatalan Faktur; cancelled Faktur still reported in the SPT Masa PPN of the issue period
Nota Retur (sales return)	Issued by buyer; recorded by seller as a credit

5.4 Bulk upload

Coretax accepts CSV/XML bulk upload (template in the e-Faktur module). Server-side validation produces a status report within minutes — the standard path for high-volume PKPs.

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Section 6 — e-Bupot Unifikasi

6.1 What "Unifikasi" means

Before Coretax, a withholder filed multiple separate monthly returns:

• SPT Masa PPh Pasal 23/26 via e-Bupot 23/26
• SPT Masa PPh Pasal 4(2) via e-Bupot 4(2)
• SPT Masa PPh Pasal 15 via e-Bupot 15

PER-24/PJ/2021 (introduced the original e-Bupot Unifikasi) and the broader DJP regulation set referenced under PER-2/PJ/2024 consolidated these into one monthly form: SPT Masa PPh Unifikasi. Coretax is the single venue for the unified slip workflow.

Note. SPT Masa PPh Pasal 21/26 (employment withholding on wages) is not included in the Unifikasi. PPh 21 keeps its own monthly form, but that form is also filed inside Coretax. See id-payroll-pph21.

6.2 Articles covered by the Unifikasi

Article	Typical withholding base
PPh 23	Domestic withholding on services, rent (other than land/building), royalty, interest (non-bank), dividend to non-corporate residents
PPh 26	Withholding on payments to non-residents (subject to tax treaty rates)
PPh 4(2) — Final	Land/building rent, construction services, deposit interest, lottery prizes, certain UMKM final tax
PPh 15	Specific industries — shipping, aviation, oil & gas drilling services, etc.

6.3 Issuance flow inside Coretax

1. e-Bupot Unifikasi → Buat Bukti Potong.
2. Pick the article — PPh 23, 26, 4(2), or 15. Form fields change accordingly.
3. Enter payee NPWP (or passport / TIN for non-residents under PPh 26).
4. Enter gross amount and tax rate. Coretax computes the withheld amount.
5. For PPh 26 — attach the DGT Form (SKD — Surat Keterangan Domisili) for a treaty rate; otherwise default 20%.
6. Sign with the digital certificate passphrase.
7. The Bukti Potong Unifikasi is issued — payee downloads it from their own Coretax profile.

6.4 Monthly SPT Masa PPh Unifikasi

At month-end Coretax aggregates all Bukti Potong issued per article. The user reviews, adjusts for voids/amendments, generates a Kode Billing, pays, then returns to attach the NTPN (Nomor Transaksi Penerimaan Negara) and lodges the SPT.

Statutory deadlines (unchanged by Coretax): SPT Masa Unifikasi due by the 20th of the following month; payment by the 10th of the following month (UU KUP). PPh 21 deadlines live in id-payroll-pph21.

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Section 7 — SPT filing channels

Coretax exposes four channels for SPT submission. Pick the channel that matches the form and the taxpayer's volume.

Channel	Used for	Notes
Coretax web portal	All forms — SPT Masa (PPN, Unifikasi, PPh 21/26), SPT Tahunan (1770, 1770S, 1770SS, 1771)	Default channel; supports inline editing and validation
Coretax Form	SPT 1770 (individual self-employed) initially; later expansion	Downloadable offline form; user fills it, then uploads the signed file back to Coretax. Phased rollout — broad availability February 2026 for SPT 1770
Coretax Mobile	SPT Tahunan 1770 SS and 1770 S for simple individual returns; profile updates; payment	iOS and Android. Convenient for employees with one source of income
Host-to-host (PJAP)	Bulk Faktur Pajak issuance, bulk Bukti Potong, automated SPT lodgement	Requires PJAP onboarding — engineering project; out of scope for this skill

7.1 Deadlines and reminders

Obligation	Deadline	Coretax reminder
SPT Masa PPN payment	End of month following the tax period	Coretax dashboard banner; email
SPT Masa PPN filing	End of month following the tax period	Same
SPT Masa PPh Unifikasi payment	10th of the following month	Coretax dashboard + e-mail nudge
SPT Masa PPh Unifikasi filing	20th of the following month	Same
SPT Masa PPh 21/26 payment	10th of the following month	Same
SPT Masa PPh 21/26 filing	20th of the following month	Same
SPT Tahunan 1770 individual	31 March of the following year	Coretax sends e-mail reminders from January
SPT Tahunan 1771 corporate	30 April (4 months after fiscal year-end)	Same
NSFP year-end return	31 March of the following year for unused serials	Coretax e-Faktur reminder

7.2 Bukti Penerimaan Elektronik (BPE)

Every successful filing generates a Bukti Penerimaan Elektronik — the electronic receipt. Save the BPE PDF to the workpaper. It carries a unique receipt number; this is the primary evidence of filing if DJP later challenges timeliness.

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Section 8 — Common implementation issues (Jan–Mar 2025)

The Coretax cutover was bumpy. Reviewers preparing a workpaper for an early-2025 period should expect to document at least one of these.

1. Login / password reset failures — "Lupa Kata Sandi" failed where the e-mail or phone on the DJP master file was stale. Fix: in-person visit to the local KPP to update contact data.
2. NSFP request delays — peak windows queued requests for days; PKPs were unable to issue Faktur Pajak in real time. Rely on a formal Pengumuman only.
3. Digital certificate migration glitches — legacy desktop e-Faktur certificates did not always migrate cleanly. Remedy: request a new certificate via Coretax Layanan.
4. PJAP integration latency — host-to-host had teething problems; documented workaround was bulk upload via the Coretax UI.
5. NPWP validation false-negatives — Coretax intermittently rejected valid counterparty NPWPs (especially 15-digit padded). Workaround: re-enter as 16-digit with leading "0".
6. SPT Masa PPN slow render — long render time for taxpayers with high invoice counts; use bulk upload.

For each, the Section 10 default applies: document the attempt, screenshot the error, retain the ticket number, file as soon as access is restored.

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Section 9 — Cutover between DJP Online and Coretax

This is the part reviewers get wrong most often. Use the table below as the routing rule.

Filing	Tax period	Channel
SPT Masa PPN (original)	December 2024 or earlier	DJP Online + desktop e-Faktur
SPT Masa PPN (original)	January 2025 onward	Coretax
SPT Masa PPN (pembetulan / amendment)	December 2024 or earlier	DJP Online (unless DJP announces a Coretax migration of legacy amendments — TBC)
SPT Masa PPN (pembetulan)	January 2025 onward	Coretax
SPT Masa PPh 23/26 (original)	December 2024 or earlier	e-Bupot 23/26 (legacy)
SPT Masa PPh Unifikasi (original)	January 2025 onward	Coretax e-Bupot Unifikasi
SPT Masa PPh 21/26 (original)	December 2024 or earlier	e-Bupot 21/26 (legacy)
SPT Masa PPh 21/26 (original)	January 2025 onward	Coretax e-Bupot 21/26
SPT Tahunan 1770 / 1771	Tax year 2024 (filed Q1 2025)	DJP Online — the 2024 annual returns filed in early 2025 mostly remained on the legacy portal (TBC — confirm against current DJP announcement)
SPT Tahunan 1770 / 1771	Tax year 2025 (filed 2026)	Coretax
Kode Billing for any tax payment	From 1 Jan 2025	Coretax (legacy DJP Online billing module sunsetted)
Faktur Pajak	From 1 Jan 2025	Coretax e-Faktur only — desktop e-Faktur Java client retired

If the routing is unclear, default to Coretax for any tax period of January 2025 onward and to the legacy environment for December 2024 and earlier. Confirm against the most recent DJP Pengumuman before lodgement.

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Section 10 — Conservative defaults

When Coretax behaves unexpectedly, prefer document-and-retry over guess-and-file.

1. System down — screenshot the error (URL + timestamp), capture the helpdesk ticket, file as soon as access is restored. Save the BPE.
2. Late filing due to outage — do NOT self-declare relief. Wait for an official DJP Pengumuman; file as soon as possible and prepare a written explanation for the KPP.
3. NSFP rejected — never back-date a Faktur Pajak. Issue once NSFP is granted.
4. Withholding article unclear — hold the filing. Mis-categorisation between PPh 23 / 4(2) / 15 / 26 requires a pembetulan, not an in-form note.
5. QR fails verification — re-issue. A Faktur Pajak with a failing QR code is not creditable.
6. Sertifikat Digital expiring — renew at least 30 days before expiry; Coretax blocks signing on lapse.
7. PIC departure — revoke access immediately; rotate the certificate passphrase if it was known to that user.
8. Always retain PDFs — Faktur Pajak, Bukti Potong, BPE. Workpapers hold offline copies for at least 10 years (UU KUP record retention).

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Section 11 — Reference material

Key legislation and regulations

Topic	Reference
Tax administration framework	UU KUP (UU No. 28/2007 sebagaimana terakhir diubah dengan UU HPP No. 7/2021)
Coretax — overall implementing regulation	PMK 81/2024 (Peraturan Menteri Keuangan tentang Ketentuan Perpajakan dalam rangka Pelaksanaan Sistem Inti Administrasi Perpajakan)
NIK-as-NPWP	PMK-112/PMK.03/2022; PER-04/PJ/2020 and amendments
Faktur Pajak (substance)	PMK-151/PMK.03/2013 and successors; DJP Circular SE-17/PJ/2014
e-Faktur	PER-16/PJ/2014 as updated; superseded operational rules folded into PMK 81/2024
e-Bupot Unifikasi	PER-24/PJ/2021 (original Unifikasi), refreshed by PER-2/PJ/2024 (operational rules for e-Bupot Unifikasi inside Coretax — confirm latest amending number)
e-Bupot 21/26	PER-2/PJ/2024 (companion provisions for employment withholding inside Coretax)
PMSE (foreign digital service providers)	PMK-48/PMK.03/2020 — independent of Coretax but reportable inside it
Penalties	UU KUP Chapter VIII (Sanksi)

Useful DJP resources

• pajak.go.id — official DJP portal (announcements, FAQs, Coretax onboarding).
• coretaxdjp.pajak.go.id — Coretax production tenant.
• DJP Kring Pajak 1500200 — taxpayer hotline.

Known gaps

• Foreign-taxpayer onboarding — DJP has signalled a dedicated 16-digit foreign ID; foreigners currently retain 15-digit NPWP padded to 16. TBC.
• Coretax Form — full SPT 1770 availability February 2026; later expansion TBC.
• Pembetulan of pre-2025 periods through Coretax — no single conclusive DJP instruction; default to legacy channel.
• PJAP integration patterns — out of scope for this skill.

Self-check before lodging through Coretax

• Tax period in the correct cutover bucket (see Section 9)
• NPWP entered in the right format (16-digit NIK or 15-digit padded)
• Digital certificate valid; passphrase known
• NSFP balance adequate for expected Faktur Pajak volume
• All Bukti Potong correctly classified by article (PPh 23 vs 4(2) vs 15 vs 26)
• DGT Form attached for any treaty-rate PPh 26
• Kode Billing paid; NTPN attached before lodging the SPT
• BPE saved to the workpaper
• Outage / delay events documented with screenshots and timestamps

Changelog

Version	Date	Change
1.0	May 2026	Initial release covering Coretax DJP from 1 Jan 2025 go-live: account activation, NIK-as-NPWP, e-Faktur inside Coretax, e-Bupot Unifikasi, SPT channels, Q1-2025 implementation issues, and DJP Online cutover routing.

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Prohibitions

• NEVER advise filing a 2025-period Faktur Pajak through the retired desktop e-Faktur client — Coretax is the only valid issuance channel from 1 Jan 2025.
• NEVER back-date a Faktur Pajak to avoid an NSFP delay.
• NEVER guess between PPh 23 / 4(2) / 15 / 26 to expedite an e-Bupot Unifikasi filing.
• NEVER self-declare an outage-based deadline waiver in the absence of a DJP Pengumuman.
• NEVER reuse or share a taxpayer's digital-certificate passphrase across reviewer or PIC accounts.
• NEVER present this skill's content as a substitute for the substantive tax skills (indonesia-vat, id-payroll-pph21, the income-tax skills) — Coretax is the platform; the tax content lives elsewhere.

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Disclaimer

Provided for informational purposes only; not tax, legal, or financial advice. Open Accountants and its contributors accept no liability. Coretax behaviour, URLs, and procedures may change without notice — cross-check against the latest DJP Pengumuman on pajak.go.id. All outputs must be reviewed by a qualified Konsultan Pajak before lodgement.

The most up-to-date version is maintained at openaccountants.com.

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