The best email clients in 2026

Across leading email tools, the landscape splits between developer-grade delivery, productivity-first inboxes, and team collaboration. Resend and peers emphasize APIs, templates, webhooks, and deliverability for transactional sending, while Superhuman targets fast triage with AI, shortcuts, and follow-up workflows. Missive stands out for shared inboxes, internal discussion, and task-driven coordination across customer-facing teams."