The verdict in three sentences
For a group that gets more than 1,000 documents a year signed across several entities, a custom approval workflow app connected to an eIDAS signature API pays for itself in under 18 months. The realistic 2026 budget in Germany is EUR 30,000 to 70,000 of development, plus EUR 1 to 3 per envelope depending on the signature level. The real gain is not the signature itself but the approval lead time, which typically drops from 9 days to 2 days thanks to automatic reminders and parallel routing.
Why a custom workflow rather than a plain signature tool
Off-the-shelf tools (DocuSign, Adobe Sign, Skribble, Yousign) handle a document with one or two signers very well. They hit their limits when routing depends on business rules: a supplier contract above EUR 50,000 must go through the CFO, an HR amendment needs legal sign-off and then the site director, delegated authority changes per entity under German Prokura and Handlungsvollmacht rules. The corporate office ends up running approvals in spreadsheets and email threads.
A custom app models those rules once, calls the signature API only at the signing step, and keeps a complete audit trail: who approved, when, on which version of the document.
| Criterion | SaaS tool alone | Custom app + signature API |
|---|---|---|
| Upfront cost | EUR 0 to 4,000 (setup) | EUR 30,000 to 70,000 |
| Recurring cost | EUR 40 to 90 per user per month | EUR 1 to 3 per envelope + EUR 200 to 500 hosting per month |
| Conditional routing (amount, entity, type) | Limited or manual | Unlimited, admin-configurable |
| Delegated authority per entity | Not handled | Handled with validity dates |
| ERP / DMS integration | Standard connectors | Custom (SAP, DATEV, SharePoint, d.velop) |
| Lead-time dashboard | Basic | Per workflow, entity and approver |
| Data reversibility | Partial export | Full, database and documents on your side |
eIDAS 2 signature levels and cost per envelope
The eIDAS regulation, revised in 2024 (eIDAS 2), defines three signature levels. The level depends on the legal risk of the document and drives the unit cost directly.
| eIDAS level | Typical use | Identity check | Cost per envelope 2026 (estimate) |
|---|---|---|---|
| Simple (SES) | Purchase orders, internal memos, routine HR approvals | Email + SMS code | EUR 0.80 to 1.50 |
| Advanced (AdES) | Supplier contracts, amendments, commercial agreements | Verified ID document | EUR 1.50 to 2.50 |
| Qualified (QES) | High-stakes deeds, public tenders, Schriftform requirements | Video-ident or in-person check | EUR 2.50 to 5 |
| Electronic seal | Minutes, certificates issued by the company | Organisation certificate | EUR 0.30 to 1 |
| Qualified timestamp | Proof of date on any document | None | EUR 0.05 to 0.20 |
| Evidential archiving (GoBD / TR-ESOR) | Retention 6 to 10 years | None | EUR 2 to 8 per GB per year |
In Germany, the written-form rule (Schriftform, section 126 BGB) can only be replaced electronically by a qualified signature, which is why the QES share is often higher than in France. For 2,500 documents a year with 60 % simple, 30 % advanced and 10 % qualified, the signature budget lands around EUR 4,000 to 5,000 per year.
What development costs, line by line
| Work package | Effort (days) | Budget 2026 |
|---|---|---|
| Scoping workshop and workflow mapping | 5 to 8 | EUR 4,000 to 6,500 |
| Workflow engine (rules, parallel, sequential) | 15 to 30 | EUR 12,000 to 24,000 |
| Signature and timestamp API integration | 6 to 10 | EUR 4,800 to 8,000 |
| Delegations, absences, deputies | 4 to 8 | EUR 3,200 to 6,500 |
| DMS or ERP connector | 6 to 14 | EUR 4,800 to 11,500 |
| Lead-time dashboard and automatic reminders | 4 to 8 | EUR 3,200 to 6,500 |
| Testing, acceptance, training across entities | 4 to 8 | EUR 3,000 to 7,000 |
Delivery takes 10 to 16 weeks. Plan for EU hosting (IONOS, Hetzner, STACKIT or a German AWS region) to stay consistent with GDPR and works council expectations, plus maintenance at 12 to 18 % of the initial budget per year.
Mini case study
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Julia, head of corporate legal at a Berlin services group with 1,200 staff, handles 2,500 documents a year across 5 subsidiaries. Each document consumes on average 45 minutes of follow-up (reminders, printing, scanning, couriering). That is 1,875 hours a year, roughly EUR 103,000 at EUR 55 per loaded hour.
After deploying a EUR 58,000 app, follow-up time drops to 10 minutes per document: 417 hours, or EUR 22,900. Annual gain: EUR 80,100, minus EUR 4,500 in signatures and EUR 8,500 in hosting and maintenance, about EUR 67,000 net. Payback comes in just over 10 months, before counting supplier contracts closed a week earlier.
FAQ
Does a simple electronic signature have legal value?
Yes, eIDAS states that an electronic signature cannot be denied legal effect solely because it is electronic. For around 60 to 70 % of a group's internal documents, the simple level at about EUR 1 per envelope is enough.
Do all contracts need a qualified signature?
No. A qualified signature (EUR 2.50 to 5) is required where German law imposes written form, and for high-stakes deeds, often 5 to 10 % of volume. The advanced level covers most commercial contracts.
How long must signed documents be kept?
Under German commercial and tax law, 6 years for business letters and 10 years for accounting records. GoBD-compliant archiving costs EUR 2 to 8 per GB per year, a few hundred euros for a mid-sized group.
Can the app connect to our existing ERP?
Yes, through API or file exchange. Allow 6 to 14 days for a SAP, DATEV or Microsoft Dynamics connector, EUR 4,800 to 11,500.
What if we change signature provider?
The app calls the API through an abstraction layer: switching provider takes 3 to 5 days of work. Signed documents and their evidence stay on your side.
Let's scope your project. Send us your 3 most frequent approval workflows and your annual volume: we will price the scope, an indicative budget and a 10 to 16 week delivery plan. 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.
