emailens.dev is an email rendering linter that detects CSS compatibility issues across 21 email clients, including Gmail, Outlook, Apple Mail, and Yahoo. It integrates with code editors, CLI tools, and CI pipelines to flag rendering problems and acts as a quality assurance checkpoint for frameworks like React Email, MJML, and Maizzle, offering framework-native fix snippets. The platform analyzes spam scores, validates links, audits accessibility, optimizes images, and verifies SPF/DKIM records. It detects mobile content overflow, visual bugs, and unresolved merge tags, while simulating dark mode. An AI builder generates self-healing email code for cross-client compatibility. The open-source core is available via npm, and a Figma plugin lets design teams preview email rendering within Figma frames. MCP server integration enables compatibility analysis through AI assistants like Claude and Cursor.
