系统与基础设施blog.fastmail.com
JMAP：一种更好的电子邮件方式
JMAP – a better way to email
2014 — 2017，它一次次回到首页
黑点是上首页（≥ 50 分）的那次投稿，空心点是没冲上去的投稿，点越大分数越高。
导读
这篇 FastMail 博客文章介绍 JMAP：一种基于 JSON/HTTP 的现代邮件访问协议，目标是解决 IMAP 在移动端同步、效率和客户端实现上的痛点。FastMail 将它作为开放标准推进，希望让邮件操作更简单、更实时。
为什么经久不衰：它既系统回应了 IMAP 的多年老问题，又坚持开放标准路线并最终进入 IETF 标准化，因此一直是邮件协议现代化讨论的经典起点。
HN 评论精选
用实际多端同步对比说明 FastMail 的体验明显快于 Gmail。
我拿 Gmail 和 FastMail 做了对比：在网页上把邮件标为已读或删除，Gmail iOS 应用要等很久甚至必须手动刷新，FastMail 几乎即时更新；反方向从手机操作，FastMail 网页也即时同步。这就是 FastMail 感觉更快的原因。
dannysu查看英文原文
Great job guys! Things like this together with CalDAV and CardDAV are reasons why I pay you guys for service. I just tried the following experiments with my Gmail and FastMail account. There's a reason why FastMail just feels faster! Try this: 1) While having the Gmail iOS app open, mark an email as read on the web 2) See how long it takes for Gmail to reflect the change 3) Now try with FastMail iOS app, see that it's faster Try this too: 1) While having the Gmail iOS app open, delete an email on the web 2) See that Gmail app never updates until you manually refresh 3) Now try with FastMail iOS app, see that it happens instantly How about the other direction? 1) Read an email on your phone 2) See that Gmail on the web never updates until manual refresh 3) Now try with FastMail... Instant update!
批评 JMAP 未强制加密，仍未解决邮件明文传输的核心问题。
为什么要设计一个新邮件协议却不把加密作为强制要求？我理解要修复现有协议的问题，但最大的问题之一就是明文传输。
driverdan查看英文原文
Why would you create a new email protocol without an encryption requirement? I understand trying to fix the existing protocol problems but one of the biggest is plaintext.
说明 JMAP 后来进入了 IETF 标准化流程。
补充后续进展：IETF 已成立 JMAP 工作组，正在推动规范成为 RFC。
nmjenkins查看英文原文
Just as an update since then: a JMAP working group was chartered at the IETF a few months ago, and is working towards bringing the spec to RFC status: https://datatracker.ietf.org/wg/jmap/about/
质疑 JMAP 的实际收益，担心大文件夹等场景的效率不如 IMAP。
看完 jmap.io 的对比，我觉得 JMAP 主要是小幅效率提升和客户端开发更容易，终端用户未必能感受到多少。移动端不需要持久连接被说成优势，但我用 K-9 的 IMAP push 很久也没觉得耗电。粗看协议，列邮箱似乎要一次取全部，而 IMAP 可按层级取；我曾维护数千文件夹的归档，IMAP 启动只要几 KB，JMAP 可能要传大量数据。也许我对少见场景的判断有误。
mike-cardwell查看英文原文
After reading the "Why is JMAP better than IMAP?" section on http://jmap.io/, what it seems to boil down to is small efficiency gains and an easier time for people writing clients. It doesn't look to me like users of clients will really gain much from their client using JMAP instead of IMAP. There's a comment about not requiring a persistent connection being better for mobile clients, but I've been using IMAP push with K-9 on my phone for a long time now, and I've never noticed a degraded battery life from using it. A quick look at the protocol looks like in order to get a list of mailboxes, you have to ask for them all. In IMAP, you can say, show me top level mailboxes, show me direct child mailboxes of mailbox x, etc. In a previous role, I was responsible for working on a mail archiving solution which had a large hierarchy of folders (into the thousands IIRC) in a single account. Access to the archive was via IMAP. Looks to me that JMAP here would require the client to potentially fetch megabytes of data just to start showing a list of folders, where the solution we had with IMAP probably took a couple of kilobytes at most to get started. It does make me think that the protocol may have been designed with less thought for uncommon use cases than IMAP was, but I've only spent a few minutes looking at the protocol, so I could be wrong.
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