From IMAP to JMAP: Why Modern Email Needs a Modern Protocol

From IMAP to JMAP: Why Modern Email Needs a Modern Protocol IMAP was standardized in 1986. That is 40 years ago — before the web existed, before smartphones, before WiFi. Yet in 2026, the vast majority of email clients still speak IMAP to their servers. JMAP (JSON Mail Access Protocol) is the IETF-standardized replacement. At Nubo.Email, we made the decision to build exclusively on JMAP, and the results speak for themselves. What is Wrong With IMAP? IMAP was brilliant for its era. But it has fundamental limitations that no amount of extensions can fix: Connection-oriented — IMAP maintains a persistent TCP connection. Drop it (WiFi to cellular, laptop sleep), and you lose state. The client must reconnect and resynchronize. Polling-based — To check for new mail, IMAP clients poll the server at intervals (typically 15-30 minutes). IDLE extensions help but are unreliable across NAT and mobile networks. Bandwidth hungry — IMAP often downloads entire message headers or bodies to detect chang