Specifications.

A statement of requirements is the list of your requirements before you request proposals. According to the project management standard DIN 69901-5, the client uses it to define, in essence, the full scope of their requirements for the contractor’s services. For a website, this means: What should it be able to do, for whom, by when, and with what budget. This is important for you as a business because, without a requirements specification, you’ll be comparing quotes that don’t include the same elements.

How a Specification Works

The requirements specification states what is needed, while the functional specification describes how it will be done. You write down what is needed, and the agency then describes its solution in the functional specification. The German government’s V-Model XT recommends generally not specifying technical solutions in the requirements specification so that the best solution can be found.

A website typically includes the following: current status with figures, goals with metrics, target audiences, page types, and who provides the content; features with priorities; requirements for load time, accessibility, and data protection; and, in the case of a relaunch, redirects, as well as the budget and timeline. You can find a ready-made outline in our website requirements specification template.

What Your Business Should Keep in Mind

Formulate each goal in a way that makes it measurable. “Modern” is not a goal, but “a data sheet accessible from the homepage in no more than two clicks” is. The Core Web Vitals are good metrics for measuring load time.

Assign a priority and an acceptance criterion to each requirement. A proven method is to categorize them as “Must,” “Should,” “Can,” and “Not this time.” This way, during acceptance testing, you can verify whether what was agreed upon has been delivered.

Make a note of who is providing the text, images, and translations. Without this information, it remains unclear who is providing them, and deadlines depend on it.

Make explicit reference to the specifications in the contract. According to Section 633 of the German Civil Code (BGB), the agreed-upon quality is the primary consideration for a work contract. There is no rule stating that specifications automatically become part of the contract. This is not legal advice.

Frequently Asked Questions About the Specifications

Who writes the requirements specification? The client—that is, you. An agency can help with this, but you should provide the goals and the current status yourself.

How long is a website requirements specification? In the six public website requirements specifications we analyzed, the requirements section ranged from two to fourteen pages. More important than the length is that each requirement be verifiable.

What is another term for "lastenheft"? Common terms include "Anforderungskatalog," "Anforderungsspezifikation," or "Kundenspezifikation," which is known in English as "Customer Requirements Specification."

You can find a template, a completed example, and a comparison of six real-world requirements specifications from public agencies in our guide, “Requirements Specifications for Websites.”