In the 2025 landscape of transactional email services, developers have a variety of options to choose from, each with distinct features tailored to different needs. Services like Knock provide infrastructure for cross-channel notifications and enable seamless integration without requiring service-specific code. Knock stands out for its ability to manage email templates, offer detailed analytics, and support notifications across multiple channels, such as in-app, push, SMS, and Slack. Other notable providers include SendGrid, renowned for its deliverability and extensive analytics; Postmark, which emphasizes inbox deliverability; and AWS SES, known for its scalability within the AWS ecosystem. Mailgun and Mailjet offer strong developer-focused and marketer-oriented tools, respectively, while Resend caters to React-based email development. Each service is evaluated based on criteria like developer experience, pricing, deliverability, ease of use, and analytics, with Knock being highlighted for its orchestration capabilities and robust workflow functionalities.