Practical ceiling on the length of a mailto: URL, in characters.
This is an observed floor across mail clients, not a published figure; Outlook on Windows binds
first. It exists because of a specific and silent failure: a client handed a URL past its limit
does NOT refuse it — it opens a draft with the body TRUNCATED, and the user sends half a message
without noticing. Hosts must check IsMailtoURLWithinLimit and fall back to the artifact
rather than risk that.
Practical ceiling on the length of a
mailto:URL, in characters.This is an observed floor across mail clients, not a published figure; Outlook on Windows binds first. It exists because of a specific and silent failure: a client handed a URL past its limit does NOT refuse it — it opens a draft with the body TRUNCATED, and the user sends half a message without noticing. Hosts must check IsMailtoURLWithinLimit and fall back to the artifact rather than risk that.