Invoice Manager

A minimal, production-usable invoice management system. PHP 8.2+, JSON file storage, no SQL database, no Node.js build step.

Features

• Admin login (session-based, password_hash)
• Clients CRUD (+ quick-add from the invoice form)
• Invoices with multiple line items, auto-incrementing numbers (INV-00001)
• Multiple payments per invoice; total / paid / balance / status always recalculated server-side
• Statuses: Draft, Unpaid, Partially Paid, Paid, Cancelled (auto-calculated unless Draft/Cancelled)
• Professional A4 invoice document (browser view identical to PDF)
• PDF download via dompdf, print-friendly CSS
• Company branding: logo, stamp, authorized signature (enable/disable each)
• Global default Terms & Conditions, overridable per invoice without touching the default
• Backup download (ZIP) and safe restore under Settings
• CSRF protection on all forms, uploads validated + randomized filenames, storage/ denied via .htaccess

Installation

1. Upload the project folder to your hosting (public_html or a subfolder).

2. Make sure storage/ is writable by PHP (755 or 775 usually works; on cPanel the owner is already correct).

3. Install Composer dependencies once:

   composer install
   

   If Composer is not available on shared hosting, run composer install locally and upload the generated vendor/ folder.

4. Open the site in a browser. You will be redirected to Initial Setup — create the admin account and company name.

5. Done. Configure logo/stamp/signature under Settings.

Requirements

• PHP 8.2+ with extensions: dom, json, mbstring, session, zip, fileinfo (all standard on cPanel/DirectAdmin)
• Apache with mod_authz_core (or mod_access_compat) for the .htaccess protection of /storage
• Composer only for dompdf/dompdf (PDF generation)

Data & Storage

All data lives in storage/ as JSON files — back up that folder and you have everything:

storage/
├── admin.json      admin account (password_hash, never plain text)
├── clients.json    all clients
├── invoices.json   invoices incl. nested payments
├── settings.json   company profile + defaults
└── uploads/        logo / stamp / signature (random 32-hex filenames)

Writes are locked (flock), atomic (temp file + rename), and keep a .bak of the previous state. Corrupted files are preserved as .corrupt-* instead of being overwritten.

Notes

• Invoice numbers are generated from Settings → "Invoice Number Prefix" + highest existing number + 1, so deleted invoices never cause number reuse.
• Payment status is derived, never stored blindly: paid = 0 → Unpaid, 0 < paid < total → Partially Paid, paid ≥ total → Paid. Draft/Cancelled invoices keep their status.
• Amounts are stored as numbers; formatting happens only at display time.