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C# Advent Two C# posts a day, December 1–25

Privacy

Last updated November 6, 2026

The short version: we collect only what we need to run C# Advent, we never sell it, and we only ever email you about C# Advent. Emails about a spot or request you've made always come, because they're part of taking part; every other email has a link to unsubscribe. If you've written for C# Advent, we keep your email address after the season so we can tell you when the next one opens, and we'll delete it whenever you ask.

Who we are

C# Advent is a community event run by volunteers. The organizers, Matt Groves and Calvin Allen, are responsible for the information on this site. hello@csadvent.christmas reaches both of them.

What we collect

  • When you sign in with GitHub: your GitHub user ID, username and profile name, and your primary email address if you've verified it with GitHub. We only ask GitHub for permission to read your email addresses, not for access to your repositories or anything else. The first time you sign in, we also read the social links on your public GitHub profile and add any Bluesky, Mastodon, LinkedIn, Facebook, Reddit or X account to your profile here, where you can change or remove it. We don't do that again unless you ask, on your profile.
  • If you wrote for an earlier season: the organizers may link the posts you published to your GitHub username, so you can see your C# Advent history when you sign in, and so they're listed together on your author page. That link only uses your public GitHub username and user ID. Like everyone with a GitHub account here, your name on those posts then links to your GitHub profile unless you gave a website. Ask us and we'll remove it. You can also ask for an older post to be added to your account, or for new links to the older posts on your account (if you moved your blog, for example): we keep your request and any note with it until an organizer decides, then for 30 days. If one of your posts is on someone else's account, email us and we'll sort it out.
  • When you claim a spot or edit your profile: the name and link you want on the calendar, any comments for the organizers, and the social media accounts you choose to give us. Your name, link and social accounts are saved to your profile, which fills in your next claim, and you can change them there at any time.
  • When you sign up for announcements: your email address, which we confirm with a link before sending you anything else, and whether you'd like each day's new posts during Advent too. You don't need to sign in, and it isn't linked to anything else.
  • When you join the backup list: the name and link you'd want on the calendar, any notes for the organizers, and, if you fill in for someone, your post's title and address.
  • When your entry is on the calendar: your name, your website, a link to your GitHub profile, the social media accounts you gave us, and your post's title, address and summary (if you add one) are public, on the calendar, your entry's page, your author page (every post you've written for C# Advent, once each is revealed), in the archive and its search, and in our posts about it. Once your post is revealed, a new link you give us on My spots is a request an organizer checks, kept like the requests for new links below.
  • When your post goes up: from the day before it's revealed, and whenever you ask us to check it on My spots, we read the top of your post, as anyone can see it, to check that it opens with the C# Advent blurb, and we keep what the check found: whether the blurb is there, the blurb's words, and why. When you ask, we also note who asked and when. On your post's day, and again once the season is over, we ask the Internet Archive's Wayback Machine to save a copy of it (we give it only your post's address), and keep where the copy is. Once the season is over, we also check now and then that your post is still at its address (we only ask for the page, and don't read it), and keep what we found. If it's gone, we send readers to a copy the Wayback Machine saved, if there is one.
  • When you visit: our hosting keeps diagnostic records of requests, such as the page, how long it took, and any errors, with an approximate location (country and city). Your IP address is used to find that location and then thrown away, not stored.
  • When you open or click a post: we count each time one of our links takes someone through to a post, with the time and which link it was (for example our Bluesky post or the calendar). Each author sees how their own posts did, and each season's retrospective shows the season's totals and its ten most-read posts. Nothing about you is recorded: no IP address, cookie or browser details.

Cookies

We only use the cookies the site needs to work: one that keeps you signed in, one that protects our forms from forgery, and a short-lived one while you sign in with GitHub. There are no analytics, advertising or third-party tracking cookies. Our emails don't track whether you open them or click their links.

How we use it

  • To review claims and put your entry on the calendar.
  • To email you about C# Advent: that we received your claim and what the organizers decided, reminders before your day if we don't have your post's link yet, and anything else about your spot.
  • To ask backup posters, one at a time in sign-up order, to fill a spot whose author dropped out or hasn't sent their post.
  • To check that each post opens with the C# Advent blurb. We fetch the post ourselves and send only the public text at its top to Claude, Anthropic's AI model, which answers whether the blurb is there. It never gets your name, email address or anything else we hold about you. If the blurb is missing, we email you, and an organizer can see Claude's answer.
  • If you signed up for announcements, to email you when each season's sign-ups open, and now and then with news from the organizers.
  • If you asked for the daily posts too, to email you each day's new posts from December 1 to 25. Every one of those emails has a link that turns them off and keeps you on the announcements list.
  • If you've had a spot, to let you know when the next season's sign-ups open. Unsubscribe from any of those emails, and we'll stop.
  • During Advent, to send everyone with a spot a daily email with the new posts, so they can help share them. Every one of those emails has a link that turns them off.
  • To tag you when we share your post on C# Advent's social media accounts, and to link to you from your entry's page, using only the accounts you gave us.
  • To keep the site secure and working.

We use your information because you asked to take part, and to keep the site running safely. We never sell or rent it, we never use it for advertising, and we only email you about C# Advent.

Who else sees it

The organizers see everything you send us: Matt, Calvin, and anyone else the organizers invite to help run the site. A few services run the site for us and handle information only to do that: Microsoft Azure (hosting, the database, diagnostics, and sending our emails), GitHub (sign-in), Anthropic (Claude, which checks the public text at the top of each post for the blurb), and the Internet Archive (which we give only each post's public address, to save a copy of it, or to find one once it's gone from its site).

How long we keep it

  • Unsubscribing: emails about a spot, request or backup offer you signed up for, such as an approval or a reminder that we don't have your post's link yet, always come and have no unsubscribe link. Every other email has one, which stops all of our optional emails to that address: announcements, the daily posts during Advent, and invitations to future seasons. You can turn them back on from the same page or your profile. To remember not to send them, we keep a one-way fingerprint of the address, not the address itself, until you do.
  • Authors' email addresses: if you've had a spot, we keep the email address saved with your account, and the one we have for your spot, after the season, so we can tell you when the next season's sign-ups open. Your account's address is updated from GitHub each time you sign in. Ask us and we'll delete them.
  • Claim requests and the backup list: on February 1 after each season, we automatically delete that season's claim requests and comments, and its backup list, with our note of who we've already sent the backup list's welcome email. If you've never had a spot, we delete the email address saved with your account then too, unless you're still waiting to hear about a request to add an older post to your account or for new links; the next time you sign in, GitHub gives us your current address again.
  • Requests to add an older post to your account, or for new links to your posts: deleted 30 days after an organizer decides them, or after you withdraw one.
  • Your account: your GitHub user ID and username, and the name, link and social media accounts on your profile, so we can credit your entries and fill in your next claim for you. Ask us and we'll delete them.
  • If you help run the site: the GitHub username you were invited as, your GitHub user ID once you've signed in, and who invited you and when, until you're no longer an organizer.
  • Calendar entries: kept as part of the archive, and once a season is over, in the archive files we keep with the site's code (the calendar as it's shown, nothing private), so the archive can always be rebuilt. Ask us if you'd like yours taken down.
  • Blurb checks: the latest answer about each post is kept with the calendar. It's about your post's public text, not about you. When you ask us to check your post, we note who asked and when for 31 days, so we can limit how often anyone asks, then delete it.
  • Emails we send you: each one waits in our outgoing queue, with your address, until it's sent, usually within minutes. We keep a copy for 7 days after it's sent (or after we give up on sending it), so we can look into any problem, then delete it.
  • Diagnostic records: up to 90 days.
  • Announcements: your email address, and which announcements and daily posts we've sent it, until you unsubscribe with the link in every announcement, which deletes them. Turning off the daily posts keeps you on the list. If you never confirm your address, we delete it after 7 days.
  • Database backups: 35 days, so anything we delete is gone from backups after that.

Your choices

You can change the name, link and social accounts on your profile yourself whenever you're signed in. For anything else, email hello@csadvent.christmas to see, correct or delete the information we have about you, or to take down an entry. We'll reply within 30 days. If you're unhappy with how we've handled your information, you can also complain to your local data protection authority.

Changes

If we change how we handle information, we'll update this page and the date at the top. See also our terms.