Term · Web & development
Technical specification
A technical specification — often called a "TZ" (from the Russian "техническое задание") in the region — is a document that describes what a website or software system must do, in enough detail to estimate, build and accept it. It is more detailed than a brief and is usually written together with the developer.
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Explained
What it typically contains
- Goals and scope: what the system is for and what is included.
- Users and roles: who uses it and what each role can do.
- Functional requirements: features, scenarios and business rules, often as user stories with acceptance criteria.
- Content and structure: pages, content types, languages.
- Integrations: systems to connect, data exchanged, APIs.
- Non-functional requirements: performance, security, accessibility, supported browsers and devices, hosting.
- Acceptance criteria: how the result will be checked.
- Out of scope: what is explicitly not included.
When it is needed
- Fixed-price projects, where scope must be precise.
- Formal procurement and tenders.
- Complex systems with many stakeholders.
For evolving products developed iteratively, a lighter backlog of user stories often works better than a large upfront document.
Brief vs specification
A brief describes needs in business terms and helps developers propose solutions. A specification describes the agreed solution in detail. Many projects start with a brief, then create the specification during a discovery stage.
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FAQ
Frequently asked questions
Who should write the specification?
The client provides requirements and decisions; the developer structures them and adds technical detail. Writing it together avoids misunderstandings.
Can the specification change?
Yes, through an agreed change process that adjusts estimates and timelines.