ISO datetimes in search query do not work

[MrGreenTea]

I was testing ISO date strings like 2026-06-11T12:00:00 in after: queries against /api/v1/search, which are supported by dateparse. These get dropped as invalid by mailpit and all messages are returned.

This is likely because mailpit first uses cleanString on the date, which is then rejected as invalid by dateparse because of the lowercase t.

Transparency note: I found the probable cause with GPT-5.5 in my pi-coding-agent harness. No LLM generated text has reached this issue though :)

[axllent]

Hi @MrGreenTea. Are you sure the search queries are getting dropped? These formats should work which include 2009-08-12T22:15:09 (the same format you stated). It's worth noting that all dates & times in Mailpit are in UTC, so if you're wanting a separate timezone then you must provide that too.

[axllent]

Sorry, I completely retract my previous statement - there is definitely a bug, and you're correct as to the cause of it. The date parser has no issues with lowercased month names etc, but it fails when it comes to the lowercased t in a date like that.

Unfortunately I've just released a new version of Mailpit (security fixes), so the fix for this will be in the next release which may be another week away. Is this going to be an issue for you?

[MrGreenTea]

Thanks for the swift response. I am working around this issue by using UNIX timestamps which appear to work fine. So no rush from my side :)

[axllent]

Thanks for the confirmation. If you're using docker then the axllent/mailpit:edge will already have the fix, else it'll be in the next release.