Werkvertrag vs Time-and-Material for Austrian SaaS: Legal Mechanics and Bookkeeping

Quick verdict: under Austrian ABGB §1151, a Werkvertrag is defined by an obligation to produce an agreed result, while a Dienstvertrag is defined by services over time. A fixed fee, hourly billing, a signed Statement of Work, or a commercial time-and-material label does not decide the legal classification by itself. The actual obligations and delivery model matter. See the official text of ABGB §1151 and the WKO overview of the distinction.

This is a legal-mechanics post, not legal advice. We work with an Austrian commercial lawyer for the actual contracts. The point here is to give you the conceptual map so you can engage your own lawyer with clear questions instead of paying them to explain the basics.

What is the legal difference between Werkvertrag and Time-and-Material?

The basic ABGB distinction is between undertaking a result and undertaking services for a period. In practice, software arrangements can combine elements, and employment, social-security, tax, and civil-law classifications may ask different questions. Calling an agreement "T&M", "consulting", or "Werkvertrag" is not a substitute for checking what the parties must actually do. Wavect therefore documents the intended result or service, responsibilities, cooperation duties, pricing mechanism, and change process in the agreement.

What does Wavect's fixed-price Werkvertrag actually commit to?

When Wavect and a client choose a fixed-fee Werkvertrag, the contract identifies the agreed result, fee, assumptions, client cooperation, exclusions, milestones, acceptance criteria, and change process in the SoW. That does not put every possible delay or cost on one party. Austrian law and the contract address, among other things, client-side prevention, missing cooperation, warnings, changes, and other causes of non-performance. For defective work, ABGB §1167 refers to the general warranty provisions. Available remedies and their sequence depend on those provisions and the facts. See ABGB §1167 and the WKO summary of the current ABGB warranty regime.

How should delivery and acceptance be handled?

ABGB §1167 is a warranty provision, not a general software-acceptance procedure. ABGB §1170 states that remuneration is generally due after completion, subject to rules for work performed in parts and reimbursable expenses. Austrian law does not prescribe a universal two-to-four-week UAT period, nor does silence always equal acceptance. A software contract should therefore define delivery, test access, objective criteria, the review period, defect notices, deemed-acceptance conditions if intended and enforceable, remediation, and the effect on payment. Wavect can define an acceptance-criteria exercise during discovery, but its timing and legal effect belong in the individual agreement. See the official text of ABGB §1170.

Can a Werkvertrag include change requests?

Yes. A change process can define how either party identifies out-of-scope work, who may approve it, how price and timing are recalculated, and whether the change amends the existing result or becomes a separate order. Until a change is agreed, the consequences depend on the original contract and the facts. Recording decisions in writing reduces later disputes, but Austrian law does not make one universal change-request format mandatory for every software project.

Does payment transfer the software IP?

Not automatically. Austrian copyright itself is generally not transferred during the author's lifetime. Under UrhG §24, the author can grant a non-exclusive Werknutzungsbewilligung or an exclusive Werknutzungsrecht, and the permitted uses should be described clearly. The special default in UrhG §40b concerns software created by an employee in the course of employment; it should not be assumed for an independent contractor. A project contract should address source code, documentation, pre-existing components, open-source dependencies, exclusivity, territory, duration, modification, sublicensing, and whether the grant is conditional on payment. See the official text of UrhG §24 and the WKO guidance on copyright contracts.

Is a Werkvertrag taxed differently in Austria?

The contract label alone does not determine tax or accounting. A domestic taxable service may carry Austria's standard VAT rate, but place-of-supply rules, the parties' status, and specific exceptions must be checked. For qualifying cross-border B2B services, the tax liability may shift to the recipient under reverse charge; it is not automatic for every EU invoice. The USP guidance on cross-border services explains the general place-of-supply, UID, invoice, and reporting rules.

Bookkeeping also turns on what the client acquired and the applicable reporting framework, not whether the supplier billed milestones or hours. Under UGB §197(2), an internally generated intangible fixed asset may not be recognized, while an intangible asset acquired for consideration can raise different capitalization and amortization questions. Mixed implementation, maintenance, hosting, and licence components may need separate analysis. See UGB §197, then confirm the treatment with the company's accountant or tax adviser before signing.

"Contract clarity is risk mitigation. Vague scopes do not save legal fees, they multiply them."

What happens if the scope is ambiguous?

Austrian contract interpretation starts with the parties' intention and ordinary usage under ABGB §914. The ambiguity rule in §915 is subsidiary: for a bilateral contract, an unresolved unclear expression can be interpreted against the party that introduced it, but not every uncertainty is automatically decided against the contractor. Clear scope, assumptions, dependencies, exclusions, and acceptance evidence remain valuable risk controls. We often address these during a separate discovery and SoW phase. See our agile fixed-pricing model and the Austrian Supreme Court's explanation of §915.

When is Time-and-Material the right choice?

Time-based pricing can fit several situations:

1. The scope is genuinely unknown. Research, early prototyping, or integration work where a third-party API is undocumented may be difficult to define as a result upfront.
2. Embedded or continuing work. Ongoing capacity for a client team may suit T&M with a budget cap and prioritization rules.
3. Maintenance and small changes. Agile bug fixes, occasional feature work, and on-call support can be governed through a retainer or individual orders.

A defined result and a need for budget predictability can point toward a fixed-fee Werkvertrag, but neither model is universally better. Teams should compare uncertainty, cooperation duties, change frequency, procurement needs, and the consequences of delay or termination. See the deeper comparison with generalist agencies at Wavect vs dev agencies for how this plays out in practice.

What about Sprints inside a Werkvertrag?

Yes, parties can use Sprints as a delivery mechanism inside a Werkvertrag. Review cadence, backlog authority, and the effect of feedback or changed priorities should be agreed for the project. Iterative delivery does not by itself change the promised final result or the legal classification. The SoW should connect outcomes and acceptance criteria to the agreed governance model.

How does Wavect actually structure SaaS engagements in Austria?

Our software development service can use several engagement shapes, subject to the proposal and legal review:

• Discovery. A defined discovery result may use a fixed-fee Werkvertrag; exploratory advisory work may use another structure.
• Build. A defined build can use a fixed fee and milestones, while uncertain work can use time-based pricing or a hybrid.
• Operate. Continuing support can use a retainer, budget cap, service levels, or individual work orders.

These phases may be separate agreements or parts of one agreement. Exit rights, handover obligations, licences, payment, and dependencies must be stated in the actual contract.