A platform engineering team at a large enterprise subsidiary needed to move years of Django, AngularJS, and short-lived frontend experiments toward VueJS and a common design language. Bosun helped initiate a workflow that prepared controlled migration slices with evidence engineers could review.
Over 15 years, product functionality had accumulated across Django templates, AngularJS, and several short-lived frontend experiments. The parent company introduced a common design-language mandate, and product teams still had roadmap commitments. Platform engineering needed a path that kept teams shipping while migration work moved slice by slice.
One-off migrations are risky. Our approach is iterative, where we observe, map and identify the work, and migrate slice-by-slice. Each slice also needed context, tests, and decision history for engineers to review it with confidence.
The workflow first identified user-facing features in the selected domain slice. That inventory became the acceptance checklist for reviewing the VueJS port later, so reviewers could ask whether behavior was preserved instead of scanning a diff from scratch.
The customer relied on internal packages, shared libraries, and a common design language that sat outside public model knowledge. Bosun added discovery tools so agents could retrieve current information from the customer's environment.
Draft PRs carried generated code together with user-perspective e2e coverage, decision notes, proof of what ran, known risks, and a reviewer checklist that made the change easy to verify.
Bosun split the work into a guide-generation workflow and a domain-slice migration workflow. That kept the reusable migration pattern separate from the execution of any single frontend area.
An example migration and the matching legacy implementation.
Identify and map patterns from old to new.
A reviewable, reusable migration guide for similar frontend areas. Include patterns, a style guide, best practices, and standards.
Compare an example migration with the old implementation, identify the pattern change, and produce guidance for moving similar domain slices from the legacy frontend into the target architecture.
Select a bounded frontend area, inspect the Django and AngularJS implementation, inventory user-facing behavior, apply the migration guide, add review-focused e2e tests, run checks, and prepare a documented draft PR.
AI-generated code requires proof, explanation, tests, and context. Trust needs to be earned. The review package gives engineers the diff, summary, evidence, and verification path together.
User-facing behavior listed before porting, then reused as the acceptance checklist during review.
Boundary choices, datastructures, endpoints, design-system mapping, and implementation tradeoffs captured for the reviewer.
Page-object style tests written from a user's perspective so the migrated slice could be checked behavior by behavior.
Known limitations, manual visual-review points, and follow-up questions kept visible with the draft PR.
The team initiated a way to decompose frontend modernization into controlled, repeatable work: identify the behavior first, retrieve the right internal context, apply the migration guide, prove the slice with user-perspective checks, and return a review package to engineers.
This field work showed that legacy frontend work can be captured as a controlled workflow: scoped by domain, grounded in private context, checked against user-facing behavior, and handed back as reviewable evidence.
Bosun can help turn the first slice into a workflow your engineers can inspect, review, and run again.