Contact

Who you are writing to

My name is Nguyễn Tuấn Anh, and I publish as Tuan Em. I am a self-taught iOS developer working in Swift and SwiftUI, with Rust for everything that isn't an app, and I write this site — the blog and the books — on my own time. There is no company behind it, no team and no support desk: what you send arrives in my personal mailbox and I am the one who replies. More about me and how I got here is on the about page.

I am based in Hanoi, Vietnam, which is UTC+7. That is the practical thing to know about response times — if you write from Europe or the Americas, my reply is probably composed while you are asleep.

Where to write

Write in English or Vietnamese, whichever you are more comfortable in — Vietnamese is my first language and I answer in whichever one you used. Plain text is perfect. You do not need to apologise for your English; I did not learn mine in a classroom either.

What this address is good for

• A mistake in an article or a chapter. The most useful mail I get. Tell me which page and what is wrong, and I will fix it and credit you if you want the credit. Corrections go to the front of the queue ahead of everything else here.
• A question about something I wrote — a passage that did not land, a code sample that will not compile, a claim you think needs a caveat. If the answer is longer than a paragraph it usually becomes the next article, so you may be doing other readers a favour.
• Asking to republish or translate something. Say what you want to use and where it will appear. The answer is usually yes; the terms of use explain what needs asking and what does not.
• Work. Contract iOS work, a Swift or Rust problem your team is stuck on, technical writing or review. Tell me the problem, the rough timeframe and whether it is remote — I will give you a straight yes or no rather than leaving it open.
• Anything about your data — a copy of what is held, a deletion, a question about the advertising on these pages. What the answer will be is set out in the privacy policy.
• An ad on this site that looks fraudulent or offensive. Google picks them, not me, but I can block a specific advertiser once I know about it.

One of my apps

A bug, a feature request, or deleting an app account goes to the same address, but the support page is worth reading first: it lists the five details that turn a bug report into a fix, and explains why a refund has to go through Apple or Google rather than through me.

How long a reply takes

Usually within two working days. I am one person with a job, so a message sent on Friday evening is answered on Monday, and a long technical question sometimes waits for a weekend when I can answer it properly rather than badly. If a week goes by with nothing, write again — it means the first one was filed as spam, not that I ignored you.

Requests about your own data are answered within a month at the outside, which is what the law asks and far longer than it actually takes.

What I will not answer

Not out of rudeness — these just have no good ending, and saying so up front saves us both the wait:

• Guest posts and paid links. Nobody else writes on this site and no link here is bought. Offers to "contribute an article", insert a link into an existing post, or buy a do-follow mention are deleted unread.
• SEO, marketing and outsourcing pitches. Also anything beginning with a compliment about my "amazing blog" that does not name a single thing on it.
• "Please build my app idea for free", or writing someone's homework, take-home exercise or interview task.
• Debugging a large private codebase from a screenshot. I am glad to look at a small reproducible example, and cannot take on a whole project as a favour.