# Oracle APEX Invoice Generator: Simple Invoicing for Small Teams and Projects

Invoicing should not be complicated. You did the work, now you need a document with your details, the client's details, the services you provided, and a total. That is it.

The **Oracle APEX Invoice Generator** is an open-source application designed to make that process as simple as possible. Register your business and your clients once, then creating an invoice is just a few clicks: pick the client, pick your business, add service lines, done. Preview it, print it, or save it as PDF straight from the browser.

It is built entirely in Oracle APEX — no external tools or extra licenses required. If you want to understand the printing technique behind it (HTML + CSS + `window.print()`), the companion post [Zero-cost print in Oracle APEX: HTML and CSS only](https://en.aflorestorres.com/zero-cost-print-in-oracle-apex-html-and-css-only) covers that in detail. This post focuses on the **application itself** — the data model, the API, and the user experience.

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## How it works

The idea is: set up your data once, then reuse it on every invoice.

**Lookup tables** — you register your businesses (name, address, email, phone), your clients, and your bank/payment details. These are filled once and selected from dropdowns when you create an invoice.

![Bank Details report](https://raw.githubusercontent.com/Aftorres02/blog_app_examples/master/post_2026/6_invoice_generator_app/images/bank_report.png align="center")

**Invoices** — pick a client, a business, optionally a bank account, set the issue date, payment terms, tax rate, and any notes. Then add service lines — each with a description and an amount. The app calculates subtotal, tax, and total automatically.

**Print** — open a modal preview and click Print. The browser handles the rest.

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## The page flow

The app has five pages with a straightforward flow:

```plaintext
Invoices list (100) → Create/Edit Invoice (110) → Add Line (115, modal)
                                                 → Print (120, modal)
```

The invoices list is your home base — all invoices in one Interactive Report:

![Invoices Interactive Report](https://raw.githubusercontent.com/Aftorres02/blog_app_examples/master/post_2026/6_invoice_generator_app/images/invoice_report.png align="center")

Click any row to open the invoice form. The header fields and the service lines live on the same page, so you see everything at a glance:

![Invoice detail — form and lines](https://raw.githubusercontent.com/Aftorres02/blog_app_examples/master/post_2026/6_invoice_generator_app/images/invoice_detail.png align="center")

From here you can add or edit lines (opens a modal), or hit the print icon to preview and print:

![Print Invoice modal preview](https://raw.githubusercontent.com/Aftorres02/blog_app_examples/master/post_2026/6_invoice_generator_app/images/print_invoice.png align="center")

![Browser print dialog — Save as PDF](https://raw.githubusercontent.com/Aftorres02/blog_app_examples/master/post_2026/6_invoice_generator_app/images/print_2_save.png align="center")

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## Database design

Five tables, each with a clear responsibility:

```plaintext
invg_businesses ──┐
                  ├──► invg_invoices ◄── invg_clients
invg_bank_details ┘          │
                             │
                    invg_invoice_lines
```

`invg_businesses`, `invg_clients`, and `invg_bank_details` are lookup tables. `invg_invoices` is the invoice header (references the three lookups by FK, plus dates, terms, tax, notes). `invg_invoice_lines` holds the service lines.

All tables follow the same conventions: identity primary keys, audit columns populated via [compound triggers](https://github.com/Aftorres02/OracleApex-Invoice-Generator/tree/main/triggers), soft delete with `active_yn`, and `char` semantics on all `varchar2` columns.

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## The PL/SQL API

All business logic lives in one package: `invg_invoice_api` ([spec](https://github.com/Aftorres02/OracleApex-Invoice-Generator/blob/main/packages/invg_invoice_api.pks)). It handles soft delete, invoice number generation (`YYYY-NNN` format), and the HTML rendering.

The key function is `render_invoice_html`: it fetches the invoice with all its joins (client, business, bank), loops over the service lines, computes the totals, and returns a complete HTML fragment inside a `clob`. Sections like bank details and notes are conditionally included only when present. All user data is escaped with `apex_escape.html`.

Insert and update operations use APEX's native Automatic Row Processing — no custom DML needed.

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## Deployment

The [repository](https://github.com/Aftorres02/OracleApex-Invoice-Generator) includes a `release/_release.sql` script that runs everything in the correct order — views, packages, triggers, seed data, and the APEX application import:

```bash
cd release
sqlcl user/pass@db @_release.sql
```

Log in to APEX and your invoicing app is ready.

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## Why use this

*   **Simple** — the whole point is reducing friction. A few clicks to create an invoice, one click to print or save as PDF.
    
*   **Self-contained** — runs entirely inside Oracle APEX. No external services, no integrations to maintain.
    
*   **Yours to extend** — add a logo, change colors, add currency support, status workflows (Draft/Sent/Paid), email delivery via `apex_mail`. The codebase is small and readable.
    
*   **Open source** — fork it, adapt it, make it yours.
    

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## Get the code

*   **Full application**: [OracleApex-Invoice-Generator](https://github.com/Aftorres02/OracleApex-Invoice-Generator)
    

Clone, run the release script, and go send that invoice.

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#oracle-apex #apex #apexworld #apex-tips #oracle #orclapex #invoicing #plsql #open-source