Worried about e-invoice rules in Germany? Can Invoice-Ready make ZUGFeRD and XRechnung fast without a subscription?

Best offline ZUGFeRD invoicing tool for freelancers in Germany: Is Invoice-Ready worth €40 in 2026?

This is part 5 of a series on e-invoices. It looks at “Invoice-Ready” (Rechnung-Fertig). It is made for freelancers and small businesses that send only a small number of invoices each year. It can create ZUGFeRD invoices that can be checked (validated).

Clear note on trust and fairness

There is contact with the developer, Martin Pyka. A licensed copy was provided for testing. There is no paid partnership. No commission is earned if someone buys it. Feedback and improvement ideas were shared without payment.

Why this tool is being shown

Many e-invoice tools exist. Some are fine, but the main need here was simple:

• No subscription
• No cloud account needed
• Fast to set up
• Easy to use

Some tools felt too hard to get working quickly. Others were slow on the test system. Some needed extra parts like a certain Java version or a certain .NET setup, which was not wanted.

Fakturama (open-source) was set up and seemed usable after about two days of learning. But validating the final ZUGFeRD invoices failed in this work setup. A message was sent to the Fakturama team in January 2026, but no reply came, so it could not be used for real work.

Then the developer mentioned Invoice-Ready on X. The test version was downloaded and tried. Within about five minutes, a first test invoice was created and it validated successfully. That quick success mattered because validation was the main blocker before.

Who this tool fits (and who it may not)

Invoice-Ready is a good match if these points sound like you:

• You send fewer than about 50 e-invoices per year
• You want an on-device Windows app (no cloud)
• You want a one-time payment instead of monthly fees
• You want to test first, without a time limit

It may not fit if you need:

• Linux-first support (it started under Wine, but the screen was not usable)
• A tool that will clearly exist for many years with a large company behind it (small projects can stop)

Quick intro: what Invoice-Ready is

Invoice-Ready is a Windows app built with Electron. The download comes as a ZIP file (under 180 MB). There is no time limit for testing. In test mode, invoices show a “Test” mark. After you enter a license key, that mark goes away.

The license cost is about €40 for the current development branch.

Install steps (simple on purpose)

There is no installer, which can be a plus.

1. Download the ZIP
2. Extract it to a folder on your PC
3. Run RechnungFertig.exe
4. Pick the test data set
5. Create your first invoice using Microsoft Word or LibreOffice

After extract, it uses less than about 500 MB of disk space.

Folder structure (what matters and why)

A few files are important:

• RechnungFertig.exe: the program
• database.sqlite: your data (customers, items, templates)
• resources\convert.ps1: a PowerShell script used to detect Office and create e-invoices
• templates\: Word templates you can copy and edit

Updating can be simple: keep your database.sqlite and move it to the new program folder.

One real-world issue showed up in a special setup: Word 2000 was not detected correctly, so invoice creation failed. Editing the .ps1 logic fixed it in this case. A log file helped find the cause fast.

Templates: how you make the invoice look like yours

The tool includes Word templates with placeholders. A practical way to work:

1. Copy a template file
2. Rename it
3. Open it in Word or LibreOffice Writer
4. Change static parts (phone, bank info, logo)
5. Register the template inside the app (Templates menu)

When you register a template, the app stores it in the database and copies it into an internal uploads folder. You can set a favorite template so it is picked by default.

Setup: what you enter once

Before real invoices, you enter basic data:

• “My Data” (your address, email, bank info, tax IDs)
• Settings (invoice number logic and other options)
• Customers
• Items/services (descriptions and prices)

This takes time once, then saves time later.

Making an invoice (the fast workflow)

To create an invoice:

1. Click “New Invoice”
2. Pick the buyer (customer)
3. Add items/services
4. Choose a template
5. Optionally create an XRechnung file
6. Generate a PDF preview or a ZUGFeRD e-invoice

A very helpful feature is a “Test invoice” checkbox. It lets you make test invoices without using up real, sequential invoice numbers.

When you create the e-invoice, Word or LibreOffice uses your template to produce the PDF and the embedded invoice data (factur-x.xml). Then you pick a folder to save it.

One small drawback: the default save folder resets when you restart the program, so you may need to select your folder again.

In this test, a ZUGFeRD invoice was created and validated on ecosio.com in about five minutes. Full setup (templates + real master data + fixing small errors) took about two hours.

What worked well

These parts stood out as practical:

• Very simple interface
• Fast “from download to first valid test invoice”
• One-time purchase, runs locally on Windows
• No subscription, no cloud
• Developer responds quickly and ships fixes fast

A real example: after a change in validation rules caused invoices to become invalid, a corrected version arrived within two days, with clear guidance to avoid warnings.

The main risk to consider

The biggest risk is normal for small software projects: if development stops, future rule changes might make old versions less useful. That risk exists with most invoice tools, but it matters more when one person leads the project.

Practical advice before buying

Test it in your own setup first. A good test plan:

• Install and run the sample data set
• Create one test invoice
• Validate it with a trusted validator (like ecosio)
• Then add one real customer and one real service item
• Make sure your Word/LibreOffice version works in your environment

If all that works in under an hour, it is likely a good fit.