Common symptoms
- Console reports hydration mismatch
- Page flickers after load
- SSR page changes immediately
- Client replaces server-rendered content
React Hydration Error? Diagnose Server and Client Markup Drift
Hydration requires the first client render to agree with the server-rendered markup. Time-dependent values, browser storage, random output, client-only branches, and differing fetched data can create mismatches even when the page later looks normal.
Possible causes
- Browser-only API used during server render
- Random or time-based initial output
- Different server/client data
- Invalid HTML nesting
- Conditional rendering based on viewport before hydration
Diagnose the exact failure before choosing a repair.
Genesis separates the visible symptom from the underlying technical cause. Run the supported diagnostic first, review the evidence, and then use a matching repair only when the failure is actually verified.
- Platform scope
- React, Next.js, SSR-enabled Floot applications
- Category
- React & SSR
- Last updated
- 2026-09-13
Next step
Start with a free diagnostic. If Genesis verifies a problem and a compatible treatment exists, it will route you to the relevant Code Store product or repair path.
Run a Website Diagnostic