Billomat E-Invoicing Review 2025: The API-First Invoicing Tool for German Businesses

Billomat has been around since 2009, making it one of Germany's older cloud invoicing platforms. It has quietly built a loyal base of small businesses and developers who value its strong API and automation capabilities over flashy marketing. Since Germany's B2B e-invoicing mandate went live in January 2025, Billomat has updated its platform to support XRechnung and ZUGFeRD — we put both to the test.

We signed up for a trial account, created a series of test invoices across multiple formats, tested the REST API, and submitted the output to the KoSIT validator. Here's the detailed result.

Disclosure: This review is editorially independent. Links in this article may be affiliate links — if you subscribe through them, we may earn a commission at no extra cost to you. This does not influence our rating or conclusions. See our editorial policy.

At a Glance

Feature	Details
Product	Billomat Cloud Invoicing
Website	billomat.com
Founded	2009, Nuremberg, Germany
Target Users	SMBs, freelancers, developers needing API access
Starting Price	€9.00/month
Free Trial	14 days (all features)
XRechnung Support	✅ Native, version 3.0
ZUGFeRD Support	✅ Native, version 2.1
Peppol Support	❌ Not available
DATEV Export	✅ Standard export
Our Rating	4.0 / 5.0

What Makes Billomat Stand Out?

Billomat sits in an interesting position: it's not trying to be a full accounting suite like sevDesk or Lexware, and it's not as compliance-focused as easybill. Instead, it carves out a niche as the most API-friendly German invoicing tool, with:

• Mature REST API — one of the most complete API surfaces among German invoicing tools, available on the entry plan
• Zapier and Make (Integromat) integrations — no-code automation without developer resources
• Recurring invoices and subscription billing — well-implemented for SaaS companies and service providers
• Multi-user access — available from the Business plan for team workflows

If your business generates invoices programmatically (from a CRM, an ERP, or a custom application), Billomat's API design is worth serious consideration.

Testing E-Invoicing Compliance

XRechnung Generation

Creating an XRechnung invoice in Billomat follows a familiar workflow:

1. Go to "Rechnungen" → "Neue Rechnung"
2. Select or add a customer — for B2G invoices, add the Leitweg-ID in the buyer reference field
3. Add line items with tax rates and descriptions
4. Under document settings, select "XRechnung" as the export format
5. Click "Erstellen" to generate the XML

Observation: Billomat's interface doesn't prominently guide you through XRechnung-specific fields the way sevDesk does. The Leitweg-ID field is available but not prominently signposted. Users new to B2G invoicing may miss it. Once you know where to look, the workflow is fine.

Validation result: ✅ The exported XRechnung XML passed the KoSIT validator without errors. Conforms to XRechnung 3.0 (UN/CEFACT CII syntax).

ZUGFeRD Generation

Billomat exports ZUGFeRD at version 2.1, not the latest 2.3. This is a limitation compared to sevDesk, easybill, and Lexware. Version 2.1 still passes validation, and the "EN 16931" profile is used — so it's technically mandate-compliant. But as the German market moves toward 2.3, this could become friction.

Validation result: ✅ ZUGFeRD 2.1 (EN 16931 profile) passed validation. PDF/A-3 container confirmed correct.

Important note: The ZUGFeRD profile defaults to "EN 16931", which is the correct profile for mandate compliance. Billomat does not offer "Minimum" or "Basic" profiles that would create compliance issues.

API Testing

This is where Billomat earns its reputation. We tested the REST API on a trial account:

Authentication:

GET /api/clients
Authorization: BillomatApiKey [your-api-key]
Accept: application/json

Creating an invoice via API:

POST /api/invoices
{
  "invoice": {
    "client_id": "12345",
    "date": "2026-03-14",
    "due_date": "2026-03-28",
    "invoice_items": [
      {
        "title": "Consulting Services — Q1 2026",
        "quantity": "10",
        "unit_price": "150.00",
        "tax_name": "MwSt. 19%",
        "tax_rate": "19"
      }
    ]
  }
}

Exporting as XRechnung via API:

GET /api/invoices/{id}/xrechnung

Result: Clean, well-structured JSON responses. The API returned the XRechnung XML correctly. The documentation (available at api.billomat.com) covers edge cases reasonably well.

Zapier integration test: We set up a Zapier workflow that creates a Billomat invoice when a new row is added to a Google Sheet. Setup took about 15 minutes, and the invoice was created correctly. This kind of no-code automation is genuinely useful for small businesses that don't have development resources.

Features Worth Knowing About

Recurring Invoices and Subscription Billing

Billomat handles recurring invoices well:

• Set a billing interval (weekly, monthly, quarterly, annually)
• Choose whether to send automatically or require manual approval before sending
• Recurring invoices can generate XRechnung/ZUGFeRD exports on each cycle
• Email delivery is automated

For subscription-based services or retainer clients, this is a solid workflow that competitors handle less cleanly.

Document Management

Billomat keeps invoices, quotes, delivery notes, and credit notes in one place. The status tracking (draft → sent → paid → overdue) is clear, and the payment reminder system has configurable escalation levels (reminder 1, reminder 2, final notice).

DATEV Export

The DATEV export works but is less polished than sevDesk's or Lexware's implementation. The file format is correct, but the mapping of cost centers and account codes requires more manual configuration than competitors. If your Steuerberater uses DATEV heavily, check with them before committing to Billomat.

Pricing Breakdown (March 2026)

Plan	Monthly Price	Key Features
Solo	€9/month	1 user, unlimited invoices, API access, XRechnung/ZUGFeRD
Business	€18/month	+ Up to 3 users, recurring invoices, DATEV export
Enterprise	On request	+ Custom user limits, priority support, advanced reporting

Annual billing reduces the price by roughly 20%.

The 14-day free trial includes full Business plan features. No credit card required to start.

Value assessment: The Solo plan at €9/mo is competitive — it includes API access from day one, which most competitors reserve for higher tiers. The Business plan at €18/mo is reasonable for teams. However, if you don't need the API or advanced automation, sevDesk and easybill offer more polish at a similar price point.

Pros and Cons

What We Liked

• API available on entry plan — unlike most competitors, full API access is not gated behind the most expensive tier
• Mature automation support — Zapier, Make/Integromat integrations work reliably
• XRechnung validation passed — compliance output is correct
• Recurring billing — best implementation for subscription and retainer businesses
• 14-day trial — enough time to evaluate the API and automation features thoroughly

What Could Be Better

• ZUGFeRD stuck at v2.1 — competitors offer 2.3; may cause friction as the market standardises on the newer version
• No Peppol support — a gap that becomes more important if B2G invoicing is part of your business
• DATEV integration is basic — if you work closely with a Steuerberater using DATEV, Lexware or sevDesk will serve you better
• Interface feels dated — navigation is functional but visually behind sevDesk or Lexware
• Smaller community — fewer user forums, guides, and third-party tutorials compared to sevDesk or Lexware

Who Should Use Billomat?

Good fit:

• Developers who want API-driven invoice automation from day one without paying for an expensive plan
• SaaS and subscription businesses that need solid recurring invoice management
• Small teams (up to 3 users) who want flexible automation via Zapier or Make
• Businesses comfortable with a functional-but-not-flashy interface

Not a good fit:

• Freelancers who need German tax features like EÜR and ELSTER (use Lexware lexoffice)
• Businesses needing Peppol access (use easybill)
• Users who prioritise modern UI and mobile experience (use sevDesk)
• Businesses with heavy DATEV integration requirements (use Lexware or sevDesk)

Our Verdict

Billomat is a competent invoicing tool that earns its place in the market through API quality and automation capabilities, not feature breadth. If your priority is building invoice automation workflows — whether through direct API calls or no-code tools like Zapier — it's one of the better options in Germany under €20/month.

The ZUGFeRD 2.1 limitation and the absence of Peppol support are real gaps for compliance-focused teams. But for a developer building an integrated invoicing workflow, or a small subscription business wanting automated recurring invoices with XRechnung output, Billomat delivers the core requirements reliably.

Rating: 4.0 / 5.0

Category	Score
Ease of Use	3.8
Compliance Coverage	4.0
Support Quality	3.9
Value for Money	4.2
Overall	4.0

How to Get Started

1. Visit billomat.com and start the 14-day free trial
2. Create a test customer and generate an XRechnung invoice to verify compliance
3. If you plan to use the API, request your API key from the account settings and run through the basic endpoints
4. Set up a recurring invoice if relevant to your business model

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This review was last updated April 2026. See our full software comparison for how Billomat compares to sevDesk, easybill, Lexware, and others. Review methodology described in our editorial policy.