Could they have consciously chosen to remove that functionality?
E.g. to simplify code, or if they wanted all mails to have a domain (if, for example, they wanted to integrate with reputation systems that were domain oriented)?
Based on the incredibly basic bounce message, I suspect the problem is that the frontend eats the address before it even gets to delivery.
To your question, yes any product decision is possible, but enterprise/government people are surprisingly demanding about this stuff working because they have extremely weird requirements for routing mail to and through legacy systems. So I bet this still works at the mailer level and is broken in the UI.
I chuck IP address literals (both IPv4 and IPv6) on the list of things that you should care about for email if you're writing an MTA or an MUA but should otherwise generally not care about supporting if you're using email for something else (e.g., as a UID for login).
> but enterprise/government people are surprisingly demanding about this stuff working because they have extremely weird requirements for routing mail to and through legacy systems. So I bet this still works at the mailer level and is broken in the UI
> It’s likely that more people out there are being filtered by badly-implemented form validation than there are being filtered by their own need of hand-holding.
I wish this was asserted with evidence. The author might suggest this because they have unrealistic views of some users.
> In the year of our lord 2026, you can reasonably expect your users to know how to type their own email address - or even better, auto-input from their OS, browser, keyboard app, or password manager.
This really depends on who your users are.
I have multiple family members who have healthy memory, but can't accurately remember their email address everytime: the localpart, the domain, the syntax, everything.
Sending an email verification isn't sufficient, because if the user has typo'd ".com", they might never receive that email, and the user might never be back, or then have to escalate to support.
Meanwhile, if a site is opinionated on TLDs, they might prevent those users facing issues.
I'm sure there are many sites were users have a large variety of odd email addresses, but also there are sites that cater to mostly non-technical users within 1-2 locales, and so may find the friendliest UX is having opinionated validation.
That's why the article says "verify, not validate". Send an email, have a process for them to confirm they received it.
If the user gets the email and completes the validation, the email is valid. If they fucked up, they don't get the email and the account never gets created.
No one ever gets prevented from creating an account with a legitimate email address, as opposed to "opinionated validation" where that absolutely will happen. Speaking from years of experience having a .info domain which isn't even all that odd, and at one point using gmail-style + addresses regularly. "Opinionated validation" has forced me to use my .com domain without a plus dozens of times.
I know part of this is intentional, those who know they plan to sell your email addresses don't want you to use the plus addresses, but that doesn't make the advice to not filter addresses any less correct.
While I’m opposed to opinionated validation as well, you seem to be missing the issue it tries to solve, which is the user mistyping their email address, not receiving the verification email, and either thinking everything is fine, or thinking that the process is borked, and in any case not proceeding and not becoming your customer. The goal of opinionated validation is to inform the user about an incorrect email address immediately when they are entering it, so they can correct it right away.
Indeed, “do you really mean that?” would be useful, though I would always have the user type the correction themselves, because too many users would select “Yes” without thinking or attentively verifying.
> I have multiple family members who have healthy memory, but can't accurately remember their email address everytime: the localpart, the domain, the syntax, everything.
I got Gmail early enough that I have (my first name) dot (my last name) at gmail dot com. About twenty years ago, I started getting strange emails. At first I thought they were spam, because they were addressed to me by name but I had never joined those sites. Eventually I figured out that they were addressed to (my first name) (my last name) at gmail dot com. Which Gmail treats as the same address as the one with a dot in between.
Since I had never ever given out a version of my email address without a dot in the middle, I eventually figured out that these emails were meant for someone else who shared the same first and last name as me. But since I don't think Gmail would allow one person to register john.example@gmail.com and then later allow someone else to register johnexample@gmail.com, my name doppelganger must have registered firstnamelastname@yahoo.com, and then forgot the domain and given out firstnamelastname@gmail.com when asked for an email address. And probably never noticed that they weren't receiving emails like "Dear customer, thank you for purchasing (product). Would you like to try (other product)?", so they never realized that they were giving out the wrong email address.
I also have first.last@gmail.com (which I don’t use anymore, and just keep around), I get all kinds of private mails. Contracts, invoices, confidential material, private photos.
And of course, also automated signup mails, newsletters (which I make sure to block and report as spam, unsubscribing is a feature for newsletters that are opt-in), transactional mails etc.
People really suck at knowing what their e-mail is. The private mails are down to 1/month, the others to ~3/week, but it used to be much higher for both categories.
Oh and of course there is some kind of weird scam going on where spammers on German classifieds (Kleinanzeigen) send an e-mail to firstlast@gmail.com for whatever public first and last name of the lister is, and ask if the product is still available. No link, nothing. And all sent via gmail which has by an overwhelming majority become the biggest sender of spam for me. I guess they are trying to get someone to reply and then do some manual scam or something.
Randall estimates in the alt-text of https://xkcd.com/1279/ that there's about ¾ of a million people who just use somebody else's email on gmail without realizing it's not their email address.
Yes, and the MX check is pretty simple to implement.
But it is still lots more complicated than copying some imperfect email address regex, and for many sites, it's unlikely to even be worth spending much more effort than that.
Realistically, many sites can defacto choose to accept email addresses of few patterns. If a user's email address happens to be rejected, then they are either a non-technical user who quickly learns that they need a more commonly accepted email address, or a techie, who keeps a backup email address for these cases, and rightfully holds a grudge.
Most sites just aren't going to care enough to do anything more complex, for annoyed techies.
See also, IPv6 support.
And yes, I get annoyed if a site doesn't accept my domain-under-a-less-common-tld, or doesn't support IPv6. :)
Technically you don't need an MX record to receive mail. From RFC 5321:
> If an empty list of MXs is returned, the address is treated as if it was associated with an implicit MX RR, with a preference of 0, pointing to that host.
>I have multiple family members who have healthy memory, but can't accurately remember their email address everytime: the localpart, the domain, the syntax, everything.
But you can't do anything about that except asking them to validate their address with an email.
If you can catch 50% of user errors with some complex regex, but the other 50% such errors are uncaught, is that of any benefit during sofware design? No, because you still have to solve that problem, probably with email validation by code. You have reduced your workload by 0%, you just split it into 2 parts (unnecessarily).
> If you can catch 50% of user errors with some complex regex, but the other 50% such errors are uncaught, is that of any benefit during sofware design? No, because you still have to solve that problem, probably with email validation by code. You have reduced your workload by 0%, you just split it into 2 parts (unnecessarily).
In your example, the benefit is that users recover from the error 50% of the time at the time of registration, so it doesn't interrupt their workflow. Further, the fallback case (of contacting support, or enacting email validation, if a site chooses to implement) will see a dropoff in successful onboarding.
It is absolutely beneficial to catch 50% of errors earlier than you otherwise could. If validation fails the user is notified immediately. If you don't wait the user has to wait a bit in case the mail is just delayed.
No, IPv4 doesn't have the concept of addresses that are scoped to a particular interface.
Rfc3927 which standardizes the use of 168.254.0.0/16 for ipv4 link local was published in 2005, mentions scoped addresses but does not offer any solutions.
However, nothing really relies on ipv4 link local addressing, and most networks don't use it. It's a conceptual problem that these are interface scoped addresses and there's no (standard) way to specify them to applications, but it doesn't cause actual problems.
On the other hand, ipv6 neighbor discovery uses ipv6 link local addresses, so they have to work. And you might try to use them for other things... but then you need to pass through the scope. It's kind of ugh when it causes problems.
Depends on what you're doing I suppose? I'm able to work on Zig with both of the devices I mentioned. Of course I'm limiting the test cases to the subset that's actually relevant to the area or target I'm working on. But that would be the case on a beefy full-size laptop too; even there, the full Zig test suite would take many hours and murder the battery in the process.
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