2025’s ‘Advent of Code’ Event Chooses Tradition Over AI

Are you ready to code? Today, programmers around the world start counting the hours until Dec. 1, and 2025’s annual “Advent of Code” event. And this year there’s something new — it’s the first year with some very big changes. After 10 years of tantalizing coders with 25 two-part puzzles each year, event creator Eric Wastl explained what’s changing — and why — in a short, succinct announcement in October. But what’s equally significant is how the community reacted. anyone up for doing Advent of Code in OCaml this year? 🎄🐫 — sabine_s_ (@sabine_s_), Nov. 12, 2025 AI may be changing the world of programming, but some human holiday traditions continue. And as hundreds of thousands of coders barrel toward another year of holiday-themed puzzles — like reindeer flying through a North Pole blizzard — it’s nice to see that their shared communal excitement will be seeing yet another year. Advent of Code 2025: Fewer Puzzles for More Accessibility There’s no mistaking the widespread fondness for the site. According to its statistics page, 284,977 people solved last year’s first puzzle. (Completing a puzzle awards a “star,” and Wastl has announced that 23,170,305 stars have been awarded since the site’s launch in 2015.) In fact, 779 users have solved every puzzle, every year — earning all 500 stars. And over the years, more than a million people have collected at least one star. But speaking last year at the C++ conference CppNorth, Wastl admitted it’s hard to solve all 25 puzzles in a single year. “I try to make the beginning ones easy, and I try to make the later ones hard.” This means that while 263,746 people solved both parts of last year’s first puzzle, only 17,088 conquered its last puzzle. So for 2025, Wastl is reducing the number of puzzles from 25 to 12. “It takes a ton of my free time every year to run Advent of Code,” Wastl wrote in the site’s FAQ, “and building the puzzles accounts for the majority of that time. “After keeping a consistent schedule for ten years(!), I needed a change.” Responses on social media have been generally supportive… “Honestly, this makes it easier to participate,” posted one backend services developer. “I was never able to keep doing it every day as the holidays got closer, too much else to do!” And a Los Angeles-based engineering manager added that the event “is such a gift to all of us, whatever you give us is a blessing! I’m glad you’re able to find a balance that works for you.” On Reddit, Wastl confirmed that he’s still planning to have two parts for each puzzle (joking that “I reserve the right to some day have a 37-part puzzle!”). But will this affect the difficulty of the puzzles? “I’m still calibrating that,” Wastl posted on Reddit. “My hope right now is to have a more condensed version of the 25-day complexity curve, maybe skewed a little to the simpler direction in the middle of the curve? I’d still like something there for everyone, without outpacing beginners too quickly, if I can manage it.” advent of code 2024 in lean4 progress thread. day 1/25 — spikedoanz (@spikedoanz), Oct. 9, 2025 Global Leaderboards Removed and AI Use Policy And the event is also officially discontinuing its global leaderboard showing the fastest finishing times, which Wastl writes was “one of the largest sources of stress for me, for the infrastructure, and for many users. … What started as a fun feature in 2015 became an ever-growing problem.” One issue was “People took things too seriously, going way outside the spirit of the contest; some people even resorted to things like DDoS attacks.” But he seems especially bothered by the way the fastest times from around the world seemed to discourage others about their own programming skills. One Hachyderm user welcomed the change, saying the leaderboards had brought “a lot of dopamine for a very small amount of people (mayyyybe the top100?) and a lot of dread for everyone else.” And another user said they welcomed the changes, since they’d found the event “always took too much time towards the end.” (And “I thought the global leaderboard should’ve gone a few years ago anyways, when LLMs started being a thing.”) Thursday evening at my usual coffee shop, sipping an Earl Grey–Hot, doing some WordPress site dev, and squeezing in a little time for #AdventOfCode. — andrewhoyer (@andrewhoyer), Nov. 6, 2025 In fact, the site’s FAQ list now also specifically tells users that they shouldn’t use AI when solving puzzles. “If you send a friend to the gym on your behalf, would you expect to get stronger…? “If you want practice prompting an AI, there are almost certainly better exercises elsewhere designed with that in mind.” The FAQ even addresses users who want to use AI when competing with others on a private leaderboard, urging them to first ask the people running the board about their policies and expectations. Community Reactions to Advent of Code Changes and AI Advent of Code merchandise helps support the site’s operating costs (available at the site’s Shop link). So how did the community react? As the contest drew nigh, one fan launched a Reddit discussion just to emphasize Wastl’s no-AI admonition — and found others who agreed. “Using AI to do Advent of Code this year is like setting up a checkers board on your own, taking away all the pieces of one color, and declaring you won,” joked one Reddit commenter. “Yeah, nobody’s stopping you from doing it … but what do you get out of it?” Not everyone agreed. “I am unashamedly going to use AI this year,” one commenter responded, “because I want to learn Golang. I’m planning to get interactive training specifically geared to each puzzle.” And another wrote, “My plan is to use AI to code the input parsing. Always hated that part. After that, I plan to turn it off.” And ironically, OpenAI bought an ad in the official Advent of Code subreddit. (“Codex gets you up to speed fast with straightforward summaries so you can keep moving. All powered by ChatGPT…”) But programmer Jeroen Heijmans publishes an unofficial survey of thousands of participants each year, and since 2023 has been asking an additional question. What do you think of AI/LLMs [large language models]? “I was unprepared for the volume and general need for moderation of these answers,” Heijmans said when announcing 2024’s survey results on Reddit. More than 62% of respondents said they used “zero” AI — roughly the same percentage as in 2023 (when Heijmans first began asking the question). Multiple answers were allowed, with 31.8% selecting “AI is bad for Advent of Code” (up from the 27.0% in 2023). Additionally, 21.8% selected an even more emphatic option — “AI is horrible for Advent of Code” — a big jump from the 15.4% who selected that answer at the end of 2023. And 39.2% selected “Not again with AI” — a slight drop from the 40.7% who’d selected that answer in 2023, while 0.6% chose “Don’t know what AI/LLM means” (down from 1.0% in 2023). Not everyone is avoiding AI: 15.7% of 2024’s survey respondents said they’d used “some” AI when solving the puzzles (with an additional 0.5% saying they’d used “lots” of AI). But this figure was down slightly from 2023’s 14.1% who’d reported using “some” AI and the 0.7% who’d used “lots.” But in 2024, just 7.6% chose “AI is good for Advent of Code,” with 2.4% choosing “AI is great for Advent of Code” — a slight drop from the people who’d chosen those answers in 2023 (10.8% and 3.6%, respectively). Programming Trends and the Enduring AoC Tradition But mostly, the community just seems grateful that their December tradition continues. This year, one Reddit user even proposed a new challenge — trying to solve all the puzzles without if-then statements or other “flow control” keywords like while loops. So, what will this year’s event look like? Through the years, the most popular programming language for solving the puzzles — by far — seems to be Python, according to Heijmans’s unofficial survey, with nearly 40% of its respondents saying they used Python in 2024. (And 40% have said the same thing every year since 2018, when his survey began.) Rust has been a consistent second choice, used by more than 16% of participants in each of the last three years. For the last seven years, more than 30% of solvers use a Linux OS, according to the survey results, while the share of Windows users dropped from 40.5% in 2022 to 35.86% in 2023, and then to 33.239% in 2024. Heijmans notes that the Windows Subsystem for Linux got another 7.2% of responses in 2024, meaning that Linux and WSL together combined for more users than Windows only. And for the last four years, more than 40% report they used VS Code as their code editor. Screenshot of Eric Wastl celebrating daylight saving time on Hachyderm. And as they count down those final hours until midnight (EST, or 9 p.m. PST), some eager coders may even find themselves reading Eric’s secret greeting in the source code of the contest’s home page. “A lot of effort went into building this thing,” he tells visitors to his site, adding, “I hope you’re enjoying playing it as much as I enjoyed making it for you!” The post 2025’s ‘Advent of Code’ Event Chooses Tradition Over AI appeared first on The New Stack.