Strangler pattern
The strangler pattern is an incremental modernization approach that replaces a legacy system by gradually transferring its functionality to a new system until the legacy system can be retired.
Google Anthos in Action
The strangler fig pattern incrementally replaces parts of a legacy system with new implementations until the legacy system is reduced or removed.
- How it is used
- Guides incremental migration from a legacy application toward microservices while preserving production delivery.
- How deep it goes
- Explains the rationale, candidate-selection heuristic, and evaluation dimensions, but does not detail routing or integration mechanics.
- Examples
- Uses centralized authentication and authorization as an example of an easily decoupled feature.
- What you can do after
- Apply incremental extraction to reduce modernization risk and deliver architectural improvements through successive production releases.
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Architecture Modernization: Socio-technical alignment of software, strategy, and structure
The strangler fig pattern is a migration pattern that gradually replaces an existing system by routing increasing responsibility to a new system until the old system is no longer needed.
- How it is used
- Guides gradual modernization when replacing a legacy architecture without a complete rewrite.
- How deep it goes
- Explains routing, delegation, and responsibility transfer, but does not detail the additional risks it identifies.
- Examples
- Uses a legacy monolith, routing component, modernized subsystems, and SoundCloud’s eight-year migration as examples.
- What you can do after
- Apply incremental migration by routing requests between legacy functionality and newly modernized subsystems.
ASP.NET Core in Action, 3e
The strangler fig pattern is an incremental modernization pattern in which new functionality gradually replaces parts of an existing system until the legacy system can be retired.
- How it is used
- Guides gradual conversion of existing ASP.NET applications to ASP.NET Core when full replacement would add unnecessary risk.
- How deep it goes
- Explains the incremental strategy and names supporting tools, but stops short of detailed routing or deployment instructions.
- Examples
- Uses migration of an existing ASP.NET application one page or API at a time as the concrete example.
- What you can do after
- Apply the pattern with YARP, System.Web adapters, and Visual Studio tooling to reduce risk during ASP.NET Core migration.
Read how ASP.NET Core in Action, 3e explains strangler pattern →
Kafka for Architects
The strangler fig pattern is an incremental replacement approach in which a new implementation gradually takes over functionality from a legacy system.
- How it is used
- Guides gradual application and event-contract migration without interrupting users.
- How deep it goes
- Explains coexistence, compatibility direction, schema validation, and retirement, but stops short of implementation walkthroughs.
- Examples
- Uses concurrent producers, consumers, and channels, followed by validation and retirement of the legacy deployment.
- What you can do after
- Apply the pattern by coexisting versions, selecting compatibility direction, validating schemas, and retiring the legacy implementation.
Related concepts
- legacy systemaddresses · A legacy system is an existing software or computing system that remains in use or must be maintained despite older technologies, designs, or constraints that can complicate change.
- feature flaguses · A feature flag is a configuration control that conditionally enables, disables, or selects a software feature or behavior.
- microservice architectureused by · Microservice architecture is a software architectural style that organizes an application as independently deployable services with focused responsibilities that communicate through defined interfaces.
- YAGNI principleimplements · The YAGNI principle is a software design discipline of avoiding functionality or structure until a concrete need for it arises.
These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.