With nearly 10,000 GitHub stars and over a decade of development since 2013, Invoice Ninja is the most complete source-available invoicing platform for freelancers and small businesses — combining professional invoicing, online payments, expense tracking, and project management in a single self-hosted application. The Laravel API backend powers a React web portal and Flutter native applications for Windows, macOS, Linux, iOS, and Android, delivering a consistent experience across every device. Create professional invoices and quotes with real-time PDF preview, product libraries, custom templates, and automatic tax calculations. Clients receive branded emails and access their dedicated portal at your custom domain to view documents, approve quotes with e-signatures, and pay with one click via Stripe, PayPal, Square, GoCardless, Authorize.net, Braintree, or Mollie. Recurring invoices with auto-billing charge saved payment methods on schedule — weekly, monthly, or annually — with automatic reminders and late fee calculations. The built-in project management suite includes Kanban boards for task organization, billable time tracking with start/stop timers, and vendor expense management with receipt attachments. Bank account synchronization via Yodlee or GoCardless automatically imports transactions for reconciliation. E-invoicing with PEPPOL network integration supports electronic invoicing standards for European and government compliance. Reports cover invoices, expenses, profit and loss, tax summaries, and aged receivables. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Elastic License v2.

Trusted by Mistral AI, PayPal, Groq, and Synthesia with over 10,300 GitHub stars and Y Combinator backing, Lago is the open-source billing engine that handles usage-based, subscription-based, and hybrid pricing models through a single API-first platform — replacing the need to build custom billing logic or depend on opaque SaaS pricing infrastructure. Real-time event ingestion via ClickHouse processes billable events with deduplication and multiple aggregation methods including count, sum, unique count, max, and weighted sum, while graduated pricing tiers, package-based billing, and percentage-based fees model any pricing strategy from simple subscriptions to complex marketplace commission structures. Automated invoice generation calculates charges according to configurable billing cycles with grace periods, proration for mid-cycle changes, and credit note issuance for refunds and adjustments. Prepaid credits enable pay-in-advance models where customers purchase credit blocks and draw down as usage accumulates, while entitlements tie feature access directly to billing plans for automated provisioning and de-provisioning. Payment orchestration integrates natively with Stripe, Adyen, and GoCardless with automatic retry logic, dunning workflows for failed payments, and multi-gateway routing. Revenue analytics provide cross-stream visibility into MRR, usage trends, churn, and revenue drivers through dedicated API endpoints. The customer portal embeds into your application for self-service invoice access and usage monitoring. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.

Named after the Bosnian word for invoice (račun) with a raccoon twist, Rachoon provides a clean self-hosted invoicing platform that handles the complete billing cycle from quotation to payment reconciliation without touching a third-party SaaS subscription. The Nuxt.js frontend serves a dashboard that surfaces revenue totals, pending balances, overdue items, and client statistics at a glance, while the AdonisJS backend manages all business logic against a PostgreSQL 16 database with TypeScript throughout the full stack. Invoice templates use Nunjucks with full HTML and CSS control—including conditional logic, loops, and custom formatting—so the rendered PDFs actually match your design intent. This is possible because Rachoon delegates PDF generation to Gotenberg, which renders invoices through headless Chrome rather than a restricted drawing API, producing output that faithfully preserves complex layouts, web fonts, and CSS grid. Client records stay organized and searchable, each linked to their invoice and quotation history with payment status tracking across pending, paid, and overdue states. Multi-currency billing with flexible tax configuration supports international operations, and all data remains on your own infrastructure. The monorepo is managed by Turborepo with a CI pipeline covering linting, PostgreSQL integration tests, build verification, and multi-platform Docker image creation for both amd64 and arm64 architectures. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.