Micro-Frontend Strangler Migration Blueprint

Role: Principal Frontend Architect specializing in distributed web applications and enterprise migration strategies.

Context

• Legacy Web Platform: {{legacy_monolith_stack}}
• Target Micro-Frontend Architecture: {{target_mfe_framework}}
• High-Priority Feature Domains: {{critical_user_journeys}}
• Cross-Application State Coupling: {{shared_state_dependencies}}
• Target CI/CD & Hosting Infrastructure: {{deployment_environment}}
• Acceptable Service Interruption Window: {{downtime_tolerance}}

Task

Generate an exhaustive, phased strangler migration plan to decompose {{legacy_monolith_stack}} into isolated micro-frontends on {{target_mfe_framework}} for {{critical_user_journeys}} without exceeding {{downtime_tolerance}}.

Method

1. Analyze the integration boundary between {{legacy_monolith_stack}} and the container shell application in {{deployment_environment}}.
2. Design the routing arbitration mechanism (edge proxy vs. client-side routing) to dynamically delegate paths between legacy and new modules.
3. Formulate the contract for {{shared_state_dependencies}}, establishing event-bus abstractions or synchronized cookie/token storage to avoid hard module coupling.
4. Define shared dependency governance (such as design system components and runtime libraries) to prevent duplicate asset payload downloads.
5. Map the step-by-step strangler sequence starting with the lowest-risk path inside {{critical_user_journeys}} up to the core transaction flows.
6. Specify automated rollback triggers, synthetic monitoring probes, and telemetry checks for client-side runtime errors.
7. Detail team ownership, independent CI/CD pipeline structures, and contract-testing workflows for parallel squad releases.

Constraints

• MUST maintain backward compatibility with legacy authentication tokens across domain boundaries.
• MUST NOT require simultaneous full-stack deployments of both legacy and modernized frontends.
• MUST establish explicit asset size budgets for the shared container shell.
• Rollback steps MUST be executable within five minutes via CDN routing switches.

Output format

• Phase-by-Phase Roadmap (Table with Phase, Scope, Routing Rule, Fallback Protocol)
• Shared State & Asset Architecture (Max 350 words detailing isolation mechanisms)
• Blast-Radius Containment & Observability Plan (Numbered list of 4-6 operational safeguards)
• Team Governance & CI/CD Delivery Model (Max 250 words)

Self-review

• Verify all 6 context variables are directly utilized in the strategic blueprint.
• Ensure no shared-state recommendations introduce single points of runtime failure.
• Confirm every migration phase includes explicit telemetry gates before proceeding.