# Architecture Means

**In short:** Architecture means are the architect's toolbox: styles, patterns, tactics, reference architectures and modelling notations. More concrete means give more structure and reuse, but they also limit the architect's freedom.

## Explanation

Architects do not start from a blank page. They draw on a toolbox of means. These means help them describe, shape and change a system.

**Styles.** An architecture style is a family of architectures that share characteristics. N-tier and microservices are examples. A style limits which elements and relationships are allowed. Those limits make desirable properties emerge. Styles do not require specific technologies, but some technologies fit certain styles better (see Architecture Style).

**Tactics.** A tactic is a design decision that influences how a system responds for one quality attribute, such as availability or performance. Quality attributes therefore guide the choice of tactics. Tactics are simpler and more primitive than patterns (see Architectural Tactic).

**Patterns.** A pattern usually balances several quality goals at once. A tactic does not. Tactics are put into practice through combinations of patterns, frameworks and code (see Architectural Pattern).

**Basic architectures.** N-tier is one example. It structures a whole application into logical layers and physical tiers. Each layer may only call the layers below it (see Layered Architecture).

**Reference architectures.** A reference architecture is a template generalized from a set of solutions. It is more concrete than patterns and styles.

**Modelling means.** Notations describe architectures. ISO/IEC/IEEE 42010 defines an architecture description language broadly as any form of expression used in architecture descriptions. So these languages count as modelling means.

**Why it matters.** The means you choose shape the fundamental decisions of the system. Those decisions are the basis for many detailed ones. They are recorded in the solution strategy (see Solution Strategy).

## Example

A team must build an online shop that stays responsive under load. They pick a style: N-tier, with a web layer, a business layer and a data layer. For fast responses, they apply a tactic. Then they implement it with a pattern and a framework. They draw the result in a standard notation. They write all these choices into the solution strategy.

## Trade-offs

More concrete means, such as a reference architecture, bring more reuse and structure. The price is that many decisions are made in advance. The architect loses freedom of choice.

Constraints from a style bring benefits but also challenges. It can be better to relax a constraint than to chase purity. Changing direction later is costly, so weigh the choice early.



## Checks

- The solution strategy records the fundamental decisions, including which styles, patterns or tactics were chosen.
- Each tactic named in the document is tied to the single quality attribute it addresses.
- For each chosen style, the document states the constraints it imposes and the trade-offs accepted.

## Related

- [Architecture Style](https://arc.fuet.ch/concepts/styles-patterns/architectural-style.md)
- [Architectural Pattern](https://arc.fuet.ch/concepts/styles-patterns/architectural-pattern.md)
- [Architectural Tactic](https://arc.fuet.ch/concepts/tactics/architectural-tactic.md)
- [Architecture Principle](https://arc.fuet.ch/concepts/principles/architecture-principle.md)
- [Layered Architecture](https://arc.fuet.ch/concepts/styles-patterns/layered-architecture.md)
- [Solution Strategy](https://arc.fuet.ch/concepts/documentation/arc42-solution-strategy.md)
- [Relationship between Tactics and Architectural Styles/Patterns](https://arc.fuet.ch/concepts/tactics/tactics-vs-architectural-styles-and-patterns.md)
- [Microservices Architecture](https://arc.fuet.ch/concepts/styles-patterns/microservices-architecture.md)

## Sources

- [Architecture Styles - Azure Architecture Center | Microsoft Learn](https://learn.microsoft.com/en-us/azure/architecture/guide/architecture-styles/) — learn.microsoft.com, accessed 2026-11-09
- [Reference architecture - Wikipedia](https://en.wikipedia.org/wiki/Reference_architecture) — en.wikipedia.org, accessed 2026-11-09
- [2.5 Design Concepts: The Building Blocks for Creating Structures | Architectural Design | InformIT](https://www.informit.com/articles/article.aspx?p=2738304&seqNum=5) — informit.com, accessed 2026-11-09
- [Architecture description language - Wikipedia](https://en.wikipedia.org/wiki/Architecture_description_language) — en.wikipedia.org, accessed 2026-11-09
- [4 - Solution strategy | arc42 Documentation](https://docs.arc42.org/section-4/) — docs.arc42.org, accessed 2026-11-09