Dunning Software Compared: Lexoffice, DATEV, sevDesk & Custom (2026)

Automated dunning is no longer a question of whether, but how. And which software is the right foundation — Lexoffice, DATEV Unternehmen Online, sevDesk, Billomat, or an orchestrated custom build — depends on details that marketing materials rarely answer honestly. This is the comparison we wished we had before guiding clients through the decision. It extends our practice-oriented overview Automate Dunning and goes one step deeper: which software actually lives up to the claim, which just shifts the effort, and when a custom workflow on Make.com or n8n pays off.

This comparison is written from the perspective of the German market (BGB, GoBD, DATEV). If you're outside Germany, the tool picks differ but the six decision dimensions apply universally.

Why the software comparison usually fails

The vendors' feature lists look similar: "Automated 3-stage dunning," "custom dunning letters," "accounting integration." Stacking these lists side by side, every tool looks the same on paper. The decisive differences hide where marketing never looks — and where your accountant sighs after three months of real operation:

• How is payment reconciliation done between dunning stages? Daily, automatically, or only when someone manually syncs?
• Legally defensible calculation per § 286 and § 288 BGB — with late fees, interest, base rate?
• Audit trail for GoBD compliance — who approved which dunning when, and how is that archived immutably for 10 years?
• Escalation and approval — can management review before the 3rd dunning, or does the tool just run through?
• Customer segmentation — may long-standing customers get longer deadlines and softer language, or does the system treat everyone identically?

That's exactly where the tools differ dramatically.

The 6 dimensions that matter in real operation

Before looking at tools individually, here's the grid every comparison should run through:

With this grid, marketing lists become comparable. And the honest answers surprise.

Lexoffice: Strong in mid-market, limits at approval workflow

Positioning: Lexoffice is the tool of choice for solo entrepreneurs up to small mid-market (up to ~30 FTEs) who want lean bookkeeping. The Office API is mature; the dunning module runs directly in the system. What Lexoffice does well:

• Real-time payment reconciliation: The banking integration (FinAPI for most German banks) pulls account status daily. Paid invoices leave the dunning run automatically.
• Configurable dunning stages: You define timing, texts, late fees per stage. The 1st dunning runs fully automated.
• Lexoffice dunning texts follow BGB requirements out of the box; interest is calculated per § 288 BGB.
• DATEV export works seamlessly for tax consultants.

Where it gets tight:

• No true approval workflow: Lexoffice runs the dunning automatically, but you can't set the 2nd or 3rd dunning to require human approval before sending. Fine if you're small. From 100 dunnings/month onward, the checkpoint is missing.
• Rudimentary customer segmentation: You can exclude individual customers (exception list) but can't run real profiles with differing deadlines and texts.
• No AI personalization: Dunning texts are templates with placeholders. Adapting tone per industry or customer history isn't possible.

Good scenario: You have 20-150 open items per month, a small customer base with similar payment patterns, and want dunning live now without a 4-week build. → Lexoffice standard suffices. Bad scenario: You have 500+ open items, a heterogeneous B2B customer mix (long-standing, new, enterprise, public sector), and don't want an automatic 2nd dunning to your top customer without finance having reviewed. → Lexoffice hits limits.

DATEV Unternehmen Online: Defensible, but not standalone

Positioning: DATEV is for companies collaborating with a tax consultancy and using the DATEV ecosystem consistently. "DATEV Unternehmen Online" (DUO) is the client platform; the actual dunning process usually runs in DATEV Rechnungswesen (at the consultancy) or Mittelstand Faktura comfort (at the company). What DATEV does well:

• Highest legal defensibility in Germany: Every DATEV process aligns with GoBD and BMF regulations. Audits become formality, not crisis.
• Integration with the consultancy: If your tax consultant works with DATEV anyway, media breaks are minimal. Payment reconciliation runs via the consultant or via DATEVconnect directly to your bank.
• Dunning deadline math follows BGB strictly and is court-defensible.
• Five- to ten-stage escalation chains are possible – including interfaces to collections services and judicial dunning proceedings (EGVP).

Where it gets tight:

• Setup complexity: DATEV isn't plug-and-play. Roles, permissions, interfaces, DATEVconnect access – typical 4-6 weeks to first production dunning, often with consultancy support.
• Email delivery usually external: DATEV generates dunning letters as PDF; delivery often runs via DATEV DMS, by post, or through an external mail service. Delivery tracking and open rates aren't built in.
• Customer segmentation exists, but complex: You need client profiles and dunning procedures per profile. Configuration is usually done by the consultancy rather than the company itself.

Good scenario: You're a mid-market firm with a tax consultancy in the DATEV ecosystem, have 200+ open items per month, and need court-defensible dunnings with full audit trail. → DATEV is the clean choice, but budget for consultancy hours. Bad scenario: You want to control dunning yourself without calling the consultancy for every adjustment, and need modern delivery receipts and click tracking. → DATEV alone becomes uncomfortable.

sevDesk: Lean, modern, quick, but with rough edges

Positioning: sevDesk positions between Lexoffice (mass) and DATEV (consultancy). Target: SMB up to 50 FTEs wanting to work independently without deep accounting knowledge. What sevDesk does well:

• Integrated dunning with configurable stages (typically 4) and automatic interest calculation.
• Email delivery directly from the tool, including PDF attachment and simple delivery receipt.
• REST API for custom extensions – more open than Lexoffice for workflow automators.
• Attractive pricing for entry.

Where it gets tight:

• Payment reconciliation sometimes delayed: Banking integration doesn't sync real-time; with some banks reconciliation takes 12-24 hours. Risk for high-frequency dunning runs.
• Less legal depth than DATEV: Sufficient for standard mid-market, limits in regulated industries or public contracts.
• Approval workflow limited: Similar to Lexoffice – dunning runs through, no intermediate approval.

Good scenario: Freelancers, agencies, or SMBs with 30-300 invoices/month wanting a modern web tool without consultancy dependency. → sevDesk delivers. Bad scenario: You have public contracts, need XRechnung-compliant outgoing invoices and court-defensible dunnings with collections/EGVP integration. → sevDesk doesn't cover everything.

Billomat: Solid niche, but small vendor

Positioning: Billomat is a long-established niche player similar to sevDesk but with a smaller user base and ecosystem. Solid for specific use cases (freelance teams, simple agency billing). Good scenario: Existing Billomat users who don't want to migrate and whose dunning volume is small. → Stay, don't switch.

The custom build case: when standard tools stop being enough

Above a certain size or complexity, every standard tool hits its own ceiling. This typically happens when three of the following apply:

>500 open items per month with heterogeneous customer base

Multiple invoicing systems in parallel (e.g., Lexoffice for DE customers, Stripe Invoicing for SaaS, Shopify invoices for e-commerce)

Strong customer segmentation required (long-standing, new, enterprise, public sector – each with own escalation profile)

Human-in-the-loop from dunning stage 2 mandatory (approval by finance or management)

Multi-channel communication (email + SMS for long-standing customers, email + letter for public clients)

Self-service installments (customer gets a link, picks plan, Stripe Billing sets it up)

Then you build an orchestrated workflow — typically on n8n or Make.com — using Lexoffice, DATEV, or sevDesk as data source while orchestrating the dunning logic yourself. Advantage: you keep control over deadlines, segments, tones, and approval paths, and can adapt without waiting for the tool vendor's next release.

How this looks concretely – including approval checkpoints, AI-personalized dunning texts, and GoBD-compliant archival – is shown in our showcase Automated Dunning & Receivables Management.

Feature matrix: side by side

Decision framework

The core mistake in tool decisions is choosing by features. The right approach: choose by customer profile + dunning volume + legal defensibility ambition:

Scenario 1: Freelancer / agency with < 50 open items/month

Recommendation: Lexoffice or sevDesk with standard dunning. Setup in an afternoon, no overhead.

Scenario 2: Mid-market with 100-500 open items/month, heterogeneous B2B customer mix

Recommendation: Lexoffice or sevDesk as data source, plus a light workflow in Make.com or n8n for customer segmentation and approval checkpoint before stage 2. That's the sweet spot — invoicing tool untouched, dunning logic orchestrated.

Scenario 3: Company with tax consultancy, regulated industry, public clients

Recommendation: Go through with the DATEV ecosystem. Dunning at the consultancy or in DATEV Mittelstand Faktura comfort. Higher effort, unmatched legal defensibility.

Scenario 4: SaaS or e-commerce with multiple invoicing sources

Recommendation: Custom build. The combination of Stripe invoicing webhooks, Shopify invoices, and Lexoffice API is too heterogeneous for any standard tool. Build on n8n or Make, plus Stripe Billing for installments.

BGB compliance: what your software must handle

Regardless of tool: for automated dunnings to hold up legally, three things must be right.

§ 286 BGB: when is the debtor in default?

Three paths to default:

Specific due date agreed (§ 286(2)(1)) — automatically from the agreed date.

Dunning after due date (§ 286(1)) — as soon as the creditor sends a dunning.

30-day B2B rule (§ 286(3)) — 30 days after invoice receipt automatically, regardless of dunning.

What your software must automate: day-accurate calculation of which path applies – and at which moment default occurs. DATEV, Lexoffice, and sevDesk can do this; for custom builds you must model the logic once cleanly.

§ 288 BGB: default interest

• B2C: base rate + 5 percentage points
• B2B: base rate + 9 percentage points

The base rate is published semi-annually by Bundesbank (~3.62% as of April 2026). Your software must pull this value automatically or at least prompt an update. Without current base rate, it produces faulty dunnings.

§ 288(5): flat €40 for B2B

Since 2014: for B2B receivables, the creditor can additionally claim a €40 flat fee – without itemized proof, without dunning fee. Many companies don't use this. A well-configured tool offers it automatically – with opt-out per customer segment (strategic customers often exempted).

GoBD: archival

Every dunning, every delivery receipt, every approval must be archived immutably for 10 years (BMF letter Nov 28, 2019). That means:

• Original PDF of the dunning
• Send timestamp
• Email recipient + delivery receipt
• Who approved (if approval workflow)
• Deadline history (when each stage triggered)

Standard tools solve this through built-in DMS. In custom builds you handle it yourself – typically S3-compatible object storage + audit log in PostgreSQL.

DSO calculation: what automation really saves

Instead of abstract "faster to cash" claims: the concrete calculation for your company.

Formula:

Working Capital Tied Up = Annual Revenue × DSO / 365

Example A: Agency with €2M annual revenue

• Current DSO: 48 days → €263,000 tied up
• After automation, DSO 30 days → €164,000
• Working capital freed: €99,000

Example B: B2B service provider with €8M annual revenue

• Current DSO: 55 days → €1.2M tied up
• After automation, DSO 32 days → €701,000
• Working capital freed: ~€499,000

The freed capital isn't a one-time effect but a permanent liquidity advantage. At a realistic 6% cost of capital, example B saves ~€30,000/year in financing costs.

Run your concrete number — and compare with annual tool and implementation costs. In nearly all cases, the investment pays back within the first quarter.

FAQ

Which is more legally defensible — Lexoffice or DATEV?

DATEV is clearly more defensible in the sense that the entire ecosystem is aligned with GoBD and BMF regulations and every dunning is court-documented. Lexoffice is legally fine for standard B2B dunnings, but for disputes with high amounts or public clients, DATEV is the cleaner choice.

Do I have to switch my invoicing software to automate dunning?

No. The pragmatic standard is to keep existing invoicing software (Lexoffice, DATEV, sevDesk) as data source and add an orchestration layer in Make.com or n8n on top. Outgoing invoices, payment reconciliation, and bookkeeping stay untouched – only dunning logic is externally orchestrated.

When does custom build become worth it over standard tools?

Pragmatic rule of thumb: switch to custom with three or more of these:

• \>500 open items per month
• Heterogeneous customer mix with multiple segment profiles
• Human approval from dunning stage 2 mandatory
• Multi-channel delivery (not just email)
• Multiple invoicing sources in parallel
• AI-personalized texts per customer

How long does implementation take?

• Lexoffice / sevDesk standard: 1-2 days for configuration, texts, first stage.
• DATEV Unternehmen Online: 4-6 weeks with consultancy coordination.
• Custom on n8n/Make: 4-6 weeks for a clean 4-stage model with segmentation and approval.

See our showcase Mahnwesen-Automation for a full project arc.

What about EGVP / judicial dunning?

When a receivable enters judicial dunning (after unsuccessful extrajudicial), it's filed via EGVP. DATEV offers this integration directly; in custom builds it can be connected; Lexoffice and sevDesk usually refer to external collections services.

Bottom line

The best dunning software isn't the one with the most features, but the one fitting your customer mix, volume, and legal defensibility ambition. Lexoffice and sevDesk are strong entries for smaller setups. DATEV is the benchmark for defensibility and consultancy integration. Custom on n8n or Make pays off above certain size and complexity — and it pays measurably from month one in lower DSO and freed working capital.

If you want to run your concrete situation through: our showcase on automated dunning shows a full 4-stage flow with approval checkpoints, self-service installments, and GoBD archive. Or book a 30-minute call on your DSO numbers – no pitch, concrete math for your case. Request call.

Related articles:

• Automate Payment Reminders – the practice overview
• Invoice Verification Automation: ZUGFeRD, XRechnung & Three-Way Match – the intake side
• Accounting Automation – the bigger picture
• DATEV Automation Practice Guide – deeper into DATEV
• Process Automation Costs – what projects realistically cost