# Turn Coretax DJP into an API

> Read unpaid kode billing (billing codes), SPT Belum Disampaikan (returns not yet filed) and faktur pajak (tax invoices) from Coretax DJP with one API call each. A workflow can check every company you act for each morning and email you the codes about to lapse.

Page: https://fous.com/automate/coretax-djp
Updated: 2026-11-12

Works with your own Coretax DJP account. Fous is an independent product.

## What you can build on Coretax

### Get unpaid billing codes

Reads Pembayaran > Daftar Kode Billing Belum Dibayar (unpaid billing codes) for the taxpayer you act for: every active code not yet paid.

- Takes: Taxpayer (NPWP or name)
- Returns: Billing code, KAP-KJS and description, tax period and year, amount, currency, expiry date

### Get returns not yet filed

Reads the SPT Belum Disampaikan (returns not yet filed) tab on Ikhtisar Profil Wajib Pajak (taxpayer profile overview) for one taxpayer.

- Takes: Taxpayer (NPWP or name)
- Returns: Return type, tax period, tax year

### Get issued tax invoices for a period

Reads the faktur pajak (tax invoices) you issued in a tax period from the e-Faktur menu, with each invoice's transaction code and status.

- Takes: Taxpayer (NPWP or name), tax period, tax year
- Returns: Invoice number, invoice date, buyer NPWP, buyer name, transaction code, DPP, PPN, status

### Create a billing code

Creates a code in Pembayaran > Layanan Mandiri Kode Billing (self-service billing code) from a KAP-KJS, period, amount and note, then downloads it.

- Takes: Taxpayer, KAP-KJS, tax period and year, amount, note (optional)
- Returns: Billing code, KAP-KJS, tax period and year, amount, expiry date

## Automate Coretax with a workflow

A [workflow](/product/workflows) runs your methods as one process, with nobody at the screen. A schedule or a call from your own system starts it, the steps run in order, and the result arrives in your inbox or in the systems you already use.

### Billing codes about to lapse, for every company you act for

Starts: Every weekday at 8:00 Jakarta time

1. For each company you name, get the unpaid billing codes in Daftar Kode Billing Belum Dibayar.
2. Keep the codes whose expiry date is within the next two days.
3. Email you the list, one section per company, with code, KAP-KJS, period and amount.

### Returns not yet filed, every Monday

Starts: Every Monday at 7:30 Jakarta time

1. For each company, read the SPT Belum Disampaikan tab of its taxpayer profile.
2. Keep the returns that were not on the list last week.
3. Post each one, with company, return type, period and year, to your task tracker's webhook.

### Last month's output tax invoices, sent to your ERP

Starts: Monthly on the 3rd at 7:00 Jakarta time

1. Get the faktur pajak issued in the previous tax period from the e-Faktur menu.
2. Post each invoice's number, date, buyer NPWP and name, transaction code, DPP, PPN and status to your ERP's webhook.

You can run a workflow by hand on every plan, Free included. Schedules and webhook triggers come with the paid plans, from $29 a month.

## Once built, one call from your code

Once you have built a [method](/product/methods), it is one POST to /v1/runs from your backend, or a tool an AI agent calls over MCP. This is what “Get unpaid billing codes” would look like.

Example request:

```
curl https://api.fous.com/v1/runs \
  -H "Authorization: Bearer $FOUS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "method": "coretaxdjp.pajak.go.id/get_unpaid_billing_codes",
    "input": {
      "taxpayer": "PT Acme Indonesia"
    }
  }'
```

Example response:

```
{
  "status": "completed",
  "data": {
    "taxpayer": "PT Acme Indonesia",
    "billing_codes": [
      {
        "billing_code": "024110000123456",
        "kap_kjs": "411126-100",
        "description": "PPh Pasal 25/29 Badan - Masa",
        "tax_period": "10",
        "tax_year": "2026",
        "amount": 48500000,
        "currency": "IDR",
        "expires": "2026-11-17"
      }
    ],
    "count": 1
  }
}
```

An example with invented data, not a ready-made endpoint. The method exists in your organization once you build it, and its name, inputs and fields follow your request.

## Coretax’s own options

DJP lists three channels for issuing faktur pajak: Coretax DJP itself, the e-Faktur Client Desktop app, and e-Faktur Host-to-Host through a PJAP, an application provider the Director General of Taxes appoints. PJAP also offer electronic withholding slips, billing codes and electronic returns. For the rest, such as the taxpayer profile and the Pembayaran lists, DJP's pages describe Coretax used by hand.

| Option | What it covers | What it takes |
| --- | --- | --- |
| e-Faktur Host-to-Host through a PJAP | Issuing faktur pajak from your own system. | An agreement with a PJAP appointed by the Director General of Taxes. |
| Other PJAP applications | Electronic withholding slips (bukti pemotongan), billing codes and electronic SPT. | An agreement with a PJAP appointed by the Director General of Taxes. |
| e-Faktur Client Desktop | Issuing most faktur pajak from a desktop app. The data reaches Coretax at the latest two days after issue. | Open to all PKP since 12 February 2025, except transaction codes 06 and 07, VAT centralised at a branch and PKP registered after 1 January 2025. |
| Coretax by hand | e-Faktur, eBupot, SPT, Pembayaran and the taxpayer profile, one taxpayer at a time. | Your own Coretax account, with a role in each company you act for. |

Read on November 12, 2026: [DJP written statement KT-06/2025 on issuing tax invoices](https://pajak.go.id/sites/default/files/2025-02/KT-06%20tentang%20Penerbitan%20Faktur%20Pajak_0.pdf), [PJAP: definition and types of service](https://www.pajak.go.id/id/pengertian-dan-jenis-layanan), [Coretax guide: PIC, impersonate and access roles for companies](https://pajak.go.id/sites/default/files/2025-01/Penanggung%20Jawab%2C%20Impersonate%20dan%20Penambahan%20Role%20Akses%20WP%20Badan%20%281%29.pdf).

## Signing in to Coretax

Coretax signs in people, not companies: staff log in with their own taxpayer account and switch to the company with impersonate, so no company password is shared. Documents are signed with the Kode Otorisasi DJP, DJP's e-signature. With Fous you sign in once through Coretax's own sign-in with your own account: the login is sealed with AES-256, never seen by code or AI agents, and an expired session is signed back in.

## Worth knowing

- **Staff act for the company through impersonate**: A company's PIC, or staff given a role, log in to their own individual account and pick the company from the account list. A method therefore takes the taxpayer as an input.
- **Drafter and Signer are separate roles**: The PIC assigns each person Drafter (prepares documents) or Signer (signs them). A new role takes effect only after that person logs out and logs in again.
- **A billing code lapses after 7 days**: A code from Layanan Mandiri Kode Billing covers one tax type and one period and stays active for 7 days. A payment counts once it has an NTPN from the Treasury.
- **Desktop invoices reach Coretax within two days**: Faktur pajak made in e-Faktur Client Desktop appear in Coretax at the latest two days after issue, so a monthly invoice pull runs a few days into the next month.

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## Frequently asked questions

### Does Coretax DJP have an API?

DJP's pages describe no API that taxpayers connect to directly. For faktur pajak, the machine channel is e-Faktur Host-to-Host through a PJAP, a provider appointed by the Director General of Taxes. PJAP also offer withholding slips, billing codes and electronic SPT. The rest of Coretax is used by hand.

### Can one person handle Coretax for several companies?

Yes. The company's PIC gives the person a role, and they switch between companies with impersonate from their own account. With Fous, a workflow can loop over the companies you act for and call the same method for each.

### How long is a Coretax billing code valid?

7 days from when it is made. After that it lapses and you create a new one. Active codes that are not yet paid are listed in Pembayaran > Daftar Kode Billing Belum Dibayar, where each can be viewed as a PDF, emailed or paid through a connected bank.

### Can I still issue faktur pajak from the e-Faktur desktop app?

Yes, for most invoices. Since 12 February 2025 every PKP may use e-Faktur Client Desktop, except for transaction codes 06 and 07, VAT centralised at a branch, and PKP registered after 1 January 2025. Those invoices reach Coretax at the latest two days after issue.

### Is Fous affiliated with the Directorate General of Taxes?

No. Fous is an independent product. You use it with your own Coretax account, and a method reads and does only what that account and its roles allow.

Fous is an independent product: it is not affiliated with, endorsed by or sponsored by the operator of Coretax DJP (Direktorat Jenderal Pajak (Directorate General of Taxes)). The name is used only to say which system this page is about. Something here wrong or out of date? Write to legal@fous.com.