I built EffiMail (https://your-domain.com) to solve a problem I faced: finding quality email productivity resources in multiple languages. What it does: Comprehensive guides on email management, privacy, and productivity Free tools: template generator, spam checker, subject line analyzer, read-time calculator Available in 6 languages (EN, ZH, JA, DE, ES, FR) Mobile-optimized with fast search and categorization Tech stack: Next.js 15 with App Router Static generation for performance i18n with next-intl Tailwind CSS for responsive design MDX for content management Why I built it: Most email productivity content is English-only, limiting accessibility for global teams. I wanted to create a comprehensive resource that works across languages and cultures. The trickiest part was handling MDX content localization while maintaining SEO performance. I ended up with a file-based approach that generates static pages for each locale. Looking for feedback on: Performance and mobile UX Translation quality (used mix of professional and AI translation) Missing features or content gaps Technical architecture suggestions Happy to answer questions about the implementation or discuss email productivity challenges you've faced.