FontFlex for Safari positions itself as a specialized accessibility extension that enables users to modify font styles and text sizes across web content. The application operates as a Safari extension, integrating directly with Apple's browser to provide real-time text rendering modifications without requiring website-specific adjustments. The core functionality centers on two primary features: font substitution and text scaling. Users can replace default website fonts with preferred typefaces from their iOS library, including system fonts and any additional fonts installed through other applications. Text size adjustments operate independently of website zoom functions, allowing for precise control over typography while maintaining page layout integrity. The extension includes preset configurations optimized for common readability challenges associated with dyslexia and ADHD. Implementation occurs through Safari's extension framework, requiring one-time activation in Settings before appearing in the browser's toolbar. Once enabled, users access modification controls through a compact interface that overlays webpage content. Testing reveals minimal impact on page loading times, though complex websites with dynamic content may experience brief reflow periods during font changes. The extension maintains modifications across browsing sessions through Safari's native data persistence. With no user reviews available at publication, assessment relies on technical evaluation and comparable market offerings. The absence of user feedback prevents analysis of long-term reliability or edge-case performance issues that typically emerge through community usage. The developer's focus on accessibility suggests prioritization of users with specific reading requirements rather than general customization audiences. FontFlex delivers competent font manipulation within Safari's technical constraints, though its utility remains niche compared to full-featured browser alternatives. The extension excels at its stated purpose of readability enhancement but lacks advanced features like color scheme modifications or text-to-speech integration found in comprehensive accessibility suites. Ideal implementation scenarios involve users seeking specific typographic adjustments without switching from Safari's ecosystem.