The verdict in three sentences
For a Munich Steuerberatung practice with around 20 staff, the strongest choice in 2026 is usually to keep DATEV as the accounting core and add a practice management layer on top. A vertical SaaS client portal wins on speed, while a custom workflow layer wins on fit once you handle more than 500 client files with unusual intake processes. Anything that cannot exchange data cleanly with DATEV and keep GoBD compliant audit trails should be ruled out at the first demo.
The 2026 ranking of software categories
We rank categories of solutions, never named agencies or vendors' private price lists. Figures are 2026 estimates for a 20 user practice.
| Rank | Solution category | Upfront cost | Recurring cost | Go live | Exit options | Best for |
|---|---|---|---|---|---|---|
| 1 | DATEV core plus vertical client portal SaaS | 3,000 to 8,000 EUR | 50 to 130 EUR per user per month | 6 to 10 weeks | Medium | Practices of 10 to 40 staff with standard workflows |
| 2 | DATEV core plus custom workflow layer | 20,000 to 45,000 EUR | 200 to 500 EUR per month | 2 to 4 months | Strong, code handed over | Practices with bespoke onboarding or advisory services |
| 3 | Fully custom practice platform | 40,000 to 110,000 EUR | 400 to 1,000 EUR per month | 4 to 7 months | Very strong | Multi office firms above 800 client files |
| 4 | All in one suite from a large accounting vendor | 5,000 to 25,000 EUR | Monthly subscription, public price varies by plan | 3 to 5 months | Weak | Firms already standardised on that vendor |
| 5 | Spreadsheets plus shared drives | Under 2,000 EUR | 10 to 25 EUR per user per month | 1 to 2 weeks | Good | Sole practitioners and very small teams |
The portal SaaS ranks first because the vendor maintains the DATEV interface, bank feeds and e-signature for you. Its weak point is lock in: ask for a written export specification covering engagement letters, deadlines and document history.
Compliance checks specific to Germany
A Munich practice faces requirements that a generic tool rarely covers out of the box.
| Requirement | What to verify | Typical extra cost if missing |
|---|---|---|
| GoBD | Immutable audit trail, 10 year retention, procedural documentation | 4,000 to 10,000 EUR |
| DATEV interface | Certified export or DATEVconnect, tested on real client data | 5,000 to 15,000 EUR |
| GDPR and professional secrecy | EU hosting, encryption, access logs, data processing agreement | 2,000 to 6,000 EUR |
| E-invoicing (XRechnung, ZUGFeRD) | Receive and archive structured invoices from clients | 3,000 to 8,000 EUR |
| Client e-signature | Qualified or advanced signature for engagement letters | 1 to 3 EUR per signature |
| Deadline engine | Federal and Bavarian tax calendars, extensions, reminders | 3,000 to 7,000 EUR |
The German e-invoicing transition makes structured invoice intake a priority for 2026: if your clients start sending XRechnung files, the portal must read and file them automatically.
Kolonell is one option for the custom layer or full platform: a medium complexity web application costs 2,500,000 to 4,000,000 FCFA (about 3,800 to 6,100 EUR) over 2 to 3 months, a complex one 4,000,000 to 8,000,000 FCFA and up (about 6,100 to 12,200 EUR) over 3 to 6 months, with maintenance at 38, 76 or 115 EUR per month.
Mini case study
Illustrative example: Thomas, managing partner of a 20 person tax practice in Munich, handles 700 client files. His team spends around 5 hours per person each week chasing receipts and checking filing deadlines. A client portal with automated deadline tracking targets 2 hours saved per person per week, or 40 hours across the practice. At a loaded cost of 55 EUR per hour over 44 working weeks, that is roughly 96,800 EUR a year. A custom workflow layer at 35,000 EUR pays back in under five months, even if only half the target is reached.
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FAQ
What should a Munich accounting practice budget for software in 2026?
Expect 50 to 130 EUR per user per month for a vertical SaaS layer, or 12,000 to 31,200 EUR a year for 20 users. A custom platform ranges from 40,000 to 110,000 EUR depending on scope.
Do we have to replace DATEV?
Almost never. In most cases the best return comes from keeping DATEV for bookkeeping and payroll and adding a portal and workflow layer around it.
How long does implementation take?
A portal SaaS goes live in 6 to 10 weeks. A custom build takes 4 to 7 months and should avoid the May to July filing peak.
How do we stay GoBD compliant with a custom tool?
Require an immutable audit log, 10 year retention and written procedural documentation in the contract. Budget 4,000 to 10,000 EUR if the vendor has not done it before.
Can we leave a SaaS vendor easily?
Only if the contract guarantees a full export in open formats within 30 days. Test a real export during the trial period.
Let's scope your project. Send us your client file count, your DATEV setup and your top three workflow pain points, and we will price a custom layer or full platform with budget and timeline. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
