Public sample. This is an analysis of the open-source repository facebook/react. Generated April 2026.
facebook/react
React — Technical debt report
The UI library from Meta. Large, heavily-studied codebase with a history of major internal rewrites (Fiber, Concurrent Mode, Server Components).
Health score
82/100
Firefighting
€16,200
per month
Debt servicing
€10,800
per month
Recovery
€84,000
one-time
AI narrative
React's codebase is a case study in managing complexity at scale. Merge discipline (94/100) is exceptional, but complexity × churn at 64/100 reflects the concentration of activity in the reconciler package — the intentional cost of keeping a highly abstract core in one place. Temporal coupling between Fiber files mirrors their deliberate co-design; refactoring here would be more risk than benefit. Recovery investment is inflated mostly by the scale of the reconciler hotspots. AI Governance at 72 reflects a moderate AI-assist signature in recent commits, all reviewed through the standard PR process.
Eight-dimensional health profile
Top hotspots
| File | Changes (6mo) | Estimated cost |
|---|---|---|
| packages/react-reconciler/src/ReactFiberWorkLoop.js | 412 | €2,450/mo |
| packages/react-reconciler/src/ReactFiberBeginWork.js | 368 | €2,180/mo |
| packages/react-reconciler/src/ReactFiberCommitWork.js | 297 | €1,760/mo |
| packages/react-dom/src/client/ReactDOMHostConfig.js | 236 | €1,400/mo |
| packages/scheduler/src/forks/Scheduler.js | 198 | €1,170/mo |
This report is a public illustration. Cost estimates assume a team of 10 developers at €450/day.