Invoice Ninja Admin Portal

The admin portal is the operator half of Invoice Ninja: the app a business owner or bookkeeper opens to raise a quote, convert it to an invoice, chase the payment, and reconcile it against a bank feed. It is a pure client — all persistence lives in the separate invoiceninja/invoiceninja Laravel server (v5), which the portal talks to over REST. A public demo backend (demo.invoiceninja.com) is wired into the login screen so you can drive the whole UI before standing up your own instance.

Why it matters

• Six platforms, one codebase. Flutter builds ship to the Microsoft Store, the Mac App Store, Snap and Flatpak on Linux, the App Store, and both Play Store and F-Droid. The F-Droid build is a genuine FOSS variant: pubspec.foss.yaml plus swapped-out OAuth, in-app-review, and upgrade-dialog files strip the proprietary dependencies rather than just relabelling the release.
• The whole money lifecycle, not just invoices. lib/redux carries a directory per entity — client, vendor, product, quote, invoice, recurring invoice, credit, purchase order, payment, payment term, expense, recurring expense, subscription, tax rate, bank account, bank transaction, transaction rule, project, task, task status, company gateway, webhook, token, design, schedule, and reports.
• Desktop is a first-class target, not a port. window_manager handles native windowing, desktop_drop accepts dragged-in receipts and attachments, and MSIX packaging is configured in pubspec.yaml.

How it works

State is Redux — flutter_redux over a store whose models are built_value immutables regenerated with build_runner. Each entity folder repeats the same shape: model, state, actions, reducer, selectors, middleware, with a matching lib/ui/<entity> folder holding the list, view, and edit screens. It is a lot of files, but the repetition means any entity is legible once you have read one.

Payments are configured, not processed, in the client: constants.dart enumerates ~29 gateway types the server can expose — credit card, bank transfer, PayPal, SEPA and BECS and ACSS direct debit, iDEAL, Bancontact, Sofort, Giropay, Przelewy24, EPS, KBC, FPX, Alipay, Apple Pay, Venmo, MercadoPago, Klarna, Bacs, and crypto — and the portal renders the right settings form per gateway. PDFs are produced through the printing package, and nimble_charts drives the dashboard.

Caveats

• Useless without a server. There is no local mode; you need an Invoice Ninja v5 backend, self-hosted or on their cloud.
• Redux boilerplate is heavy. ~14k commits of accumulated entity scaffolding, and code generation is a required build step.
• License is noassertion on the record — verify terms yourself before shipping a fork.

Deployment notes

git clone https://github.com/invoiceninja/admin-portal.git
cd admin-portal
cp lib/.env.dart.example lib/.env.dart
flutter packages pub run build_runner build --delete-conflicting-outputs
flutter run

Integration tip: the constants file also lists ~20 e-invoicing formats — EN16931, PEPPOL, the full XInvoice 1.0–3.0 range, FatturaPA, Facturae, FACT1, VERIFACTU, and Order-X. If you are evaluating open billing stacks for EU or LATAM compliance, that list is the most concrete signal in the repo.