Full-Stack Invoicing and Quotation SaaS App

Project Overview

Invoice SaaS App is a web application that lets freelancers and small business owners create, send, and track professional invoices and quotes without the friction of spreadsheets or generic templates. It covers the full lifecycle of a client transaction, from drafting a quote, to emailing it as a PDF, to converting it into an invoice with a single click once the client approves. The project was built as a complete SaaS product, including its own billing layer: a Stripe-powered credit system that gates paid actions while keeping core utilities like PDF downloads free. Key Features Professional Invoices. Invoices are generated as polished, PDF-ready documents in seconds, with fully customisable line items, taxes, and notes. Once created, they can be emailed straight to a client or downloaded as a PDF at any time. PDF downloads are always free, no credits required. Smart Quotations. Quotes follow the same polish as invoices, complete with PDF attachments sent by email and dynamic status tracking (draft, sent, approved, and so on). The standout feature here is one-click conversion: an approved quote becomes a full invoice with no re-entry of data. Instant Email Delivery. Both invoices and quotes can be emailed directly from the app with the PDF attached, keeping every client communication professional, consistent, and trackable in one place. Client Management. Every invoice and quote is linked to a client record, so the app always has full context, including contact details, history, and status, without needing to look anything up elsewhere. Dashboard Analytics. A central dashboard surfaces the metrics that matter at a glance: total invoices, quotations sent, and remaining credits, plus a feed of recent activity. Credit-Based Billing (Stripe). Rather than a flat subscription, the app uses a lightweight credit system. Creating an invoice, creating a quotation, sending an email, and converting a quote to an invoice each cost 1 credit. Downloading a PDF is always free. Every user starts with 10 free credits per month, no card required, which reset on the 1st. Users can top up anytime with one-time credit packs, and purchased credits never expire, a model designed to keep the barrier to entry low while still supporting monetisation. Authentication & Profiles. Secure registration, login, and password recovery, plus profile settings including preferred currency, so the app adapts to how each user actually invoices. Tech Stack Backend: Laravel 12 for the application framework, routing, auth, and business logic. MySQL or SQLite for the relational data layer. mPDF for server-side PDF generation. Stripe PHP for payment processing and credit-pack purchases. Frontend: React 18 for a component-driven UI. Inertia.js to glue Laravel and React together as a single-page app, without hand-building a separate REST or JSON API. Tailwind CSS for utility-first styling. Vite for a fast dev server and asset bundling. Why This Stack The Laravel, Inertia, and React combination made it possible to build a genuinely SPA-like experience, with instant navigation and no full page reloads, while keeping all business logic, validation, and PDF or email generation on the backend where it belongs. It avoided the overhead of maintaining a separate API layer just to talk to the frontend, which kept development fast without sacrificing the interactivity users expect from a modern dashboard. The credit system was the most interesting piece to design: it needed to feel generous, with free PDF downloads and a monthly free tier, while still creating a clear, fair path to revenue through Stripe-backed top-ups.