I performed a technical audit of a Next.js/React website and completed the first stage of SEO optimization. The work covered indexation checks, redirects, canonical URLs, hreflang, sitemap.xml, robots.txt, and proper 404 handling. I also fixed routing issues, multilingual URL behavior, and internal navigation logic. After the updates, the website was rebuilt, redeployed on the server, and checked for correct behavior across key SEO scenarios.