Software specifications - the basis for development

What is a specification sheet?

A functional specification is a technical document thatdescribes how the requirements from the specification sheet (or directlyfrom the customer) are to be implemented. It serves as a contractbetween the customer and the development team and describes in detailthe functions, processes, interfaces and framework conditions of thesoftware to be developed.

Why is a specification sheet important?

A good specification...

• creates transparency and trust,
• defines clear expectations,
• serves as a planning and control instrument in the course of the project,
• helps to realistically calculate cost and time frames,
• is the basis for the subsequent acceptance of the software.

Requirements specification vs. functional specification: What's the difference?

In practice, the terms requirements specification and functional specification are often used synonymously - these are two clearly differentiated documents in the software development process.

• The requirements specification describes what the software should do - it usually comes from the client and presents the requirements from a technical perspective. It contains objectives, framework conditions and the desired range of functions, without going into the technical implementation.
• The requirements specification, on the other hand, describes how these requirements are to be implemented technically - it is usually created by the development partner and forms the basis for the actual implementation.

A structured specification therefore ideally begins with a clearly formulated requirements specification. If no requirements specification is available, a joint analysis phase at the start of the project can also help to define requirements and objectives. In both cases, the requirements specification is the central link between idea and implementation in software development.

Software requirements specification example: This is what it could look like

Especially at the beginning of a project, many people find it difficult to imagine what a complete specification looks like in practice. A well-structured example of a software specification can help you get a better feel for the scope, language and level of detail.

A typical specification sheet for a software solution contains, for example

• A detailed description of the user roles and their authorizations
• Concrete processes such as login, data maintenance or automatic notifications
• Performance and availability requirements
• Technical interfaces to existing systems
• Rules on data storage and data protection

We support with concrete examples

If you are currently faced with the task of creating arequirements specification for a software project, we will be happy to provideyou with examples from practice. These can serve as a template and beindividually adapted to your requirements. This saves you time - and ensuresthat nothing is forgotten.

Specification structure: Contents at a glance

The scope may vary depending on the size of the project and the industry, but the following elements should be included in a complete requirements specification outline:

1. introduction

• Aim of the document
• Project name
• Parties involved
• Version history

2. initial situation

• Description of the current status quo
• Problems or optimization potential

3. objectives of the software

• What is to be achieved?
• What are the main business or technical objectives?

4. functional requirements

• Description of the desired functions
• Use cases or user stories
• Example: "Users can register and log in."

5. non-functional requirements

• Performance requirements
• Safety requirements
• Scalability
• Data protection

6. system architecture & technologies

• Description of the planned system environment
• Which frameworks, programming languages, databases etc. are used?

7. user interfaces (UI/UX)

• First mockups or wireframes
• Operating concepts and layout specifications

8. interfaces to other systems

• External APIs or existing systems
• Data import/export

9. test concept & acceptance criteria

• How is it tested?
• What criteria must be met for the project to be considered successful?

10. schedule & milestones

• Project phases
• Important dates
• Dependencies

11. open points / risks

• Aspects still to be clarified
• Technical or organizational risks

Tips for practice

✅ Create in close coordination: Get specialist departments, developers and stakeholders on board at an early stage.
✅ Use clear language: Avoid technical jargon or unclear wording.
✅ Visualize: Diagrams, tables or mockups make requirements more tangible.
✅ Document changes: Versioning and change logs avoid chaos.
✅ Stay realistic: Not everything has to be perfect "right from the start" - it's better to prioritize step by step.

Rights of use and source code for individual software

When developing customized software, not only technical requirements, but also legal aspects should be taken into account in the specifications. Two important points here are the rights of use to the individual software and the publication of the source code.

Rights of use for individual software

The requirements specification should already clearly regulate which rights of use the client receives for the software. Are these simple rights of use (e.g. for internal use), or does the customer receive exclusive rights that are unlimited in terms of time and space? The question of whether redistribution or commercial use is permitted should also be clearly answered.

Release of source code for individual software

Another key point is the release of the source code of the customized software. By default, the source code often remains with the service provider, unless otherwise contractually agreed. Anyone planning long-term independence or maintenance by third parties should record the handover of the source code in the specifications at an early stage. It is also advisable to include provisions on documentation, libraries used and the build environment.

Conclusion

A functional specification is far more than just a bureaucratic document. It is the foundation of any successful software development. If you take the time to draw it up carefully, you will save a lot of effort, misunderstandings - and ultimately money - later on.

Are you planning a software project?
We would be happy to support you in creating a professional specification - just get in touch.

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