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# Issue invoice

> Issue a domestic invoice for a contractor with one or more lines. Inputs, cURL, Python and Node.js examples and an example response.

Source: https://cotlet.dev/docs/api/ifirma/issue_invoice

Docs sections: [Get started](https://cotlet.dev/docs.md) · [REST API](https://cotlet.dev/docs/api.md) · [MCP](https://cotlet.dev/docs/mcp.md) · [SDKs & CLI](https://cotlet.dev/docs/sdks.md) · [Integrations](https://cotlet.dev/docs/integrations.md)

Issue a domestic invoice for a contractor with one or more lines.

iFirma API: https://cotlet.dev/docs/api/ifirma.md

`POST https://cotlet.dev/api/v1/ifirma/contractors/{contractor_id}/invoices`

Access: write. Confirm: waits for the user's OK before it runs.

Issues the invoice with the next number in the series, the same as "Wystaw". Lines need name, quantity, unit, unit price and VAT rate; a line that is not exempt may also need a PKWiU code. The invoice is not sent to KSeF or to the buyer until you call send_invoice_to_ksef or send_invoice_email. By default you confirm each call; you can switch that off for this tool.

## Parameters

| Name | Type | Required | Description |
|---|---|---|---|
| `contractor_id` | string | yes | Contractor ID from list_contractors or create_contractor. |
| `lines` | array | yes | Lines: {name, quantity, unit, unit_price, vat_rate}. vat_rate is 23, 8, 5, 0 or exempt. |
| `calculate_from` | string | no | net or gross: which price you give. Default: net. |
| `issue_date` | string | no | YYYY-MM-DD. Default: today. |
| `sale_date` | string | no | YYYY-MM-DD. Default: issue date. |
| `due_date` | string | no | YYYY-MM-DD. |
| `payment_method` | string | no | transfer, cash or card. |
| `notes` | string | no | Remarks printed on the invoice, up to 1000 characters. |

## Request

**cURL**

```bash
curl -X POST https://cotlet.dev/api/v1/ifirma/contractors/c_4817/invoices \
  -H "Authorization: Bearer $COTLET_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"calculate_from":"net","issue_date":"2026-10-14","sale_date":"2026-10-14","due_date":"2026-10-28","payment_method":"transfer","lines":[{"name":"Website retainer","quantity":2,"unit":"month","unit_price":500,"vat_rate":23}]}'
```

**Python**

```python
result = client.call("ifirma", "issue_invoice", {"contractor_id":"c_4817","calculate_from":"net","issue_date":"2026-10-14","sale_date":"2026-10-14","due_date":"2026-10-28","payment_method":"transfer","lines":[{"name":"Website retainer","quantity":2,"unit":"month","unit_price":500,"vat_rate":23}]})
```

**Node.js**

```js
const result = await cotlet.call('ifirma', 'issue_invoice', {"contractor_id":"c_4817","calculate_from":"net","issue_date":"2026-10-14","sale_date":"2026-10-14","due_date":"2026-10-28","payment_method":"transfer","lines":[{"name":"Website retainer","quantity":2,"unit":"month","unit_price":500,"vat_rate":23}]});
```

**CLI**

```bash
cotlet call ifirma issue_invoice --data '{"contractor_id":"c_4817","calculate_from":"net","issue_date":"2026-10-14","sale_date":"2026-10-14","due_date":"2026-10-28","payment_method":"transfer","lines":[{"name":"Website retainer","quantity":2,"unit":"month","unit_price":500,"vat_rate":23}]}'
```

## Example response

```json
{
  "id": 7020118,
  "number": "41/2026",
  "draft": false,
  "buyer": "Blue Fern Studio",
  "net": 1000,
  "vat": 230,
  "gross": 1230,
  "currency": "PLN",
  "issue_date": "2026-10-14",
  "due_date": "2026-10-28",
  "ksef_status": null
}
```

Previous: [Save invoice draft](https://cotlet.dev/docs/api/ifirma/save_invoice_draft.md)
Next: [Send invoice to KSeF](https://cotlet.dev/docs/api/ifirma/send_invoice_to_ksef.md)

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## For AI agents: sign your user up

Is your user asking you to sign them up for Cotlet? You can do it for them, no account or key needed.

1. Read the fields and their allowed values: GET https://cotlet.dev/api/v1/access-requests
2. Ask the user for each value: email, apps, what you will do with them. If they leave the password to you, generate a strong one and show it to them.
3. Show the user what you will send, then POST it as JSON to https://cotlet.dev/api/v1/access-requests.

One call creates the account and sends the access request; we email the user when access is granted.