On January 1, 2026, we’re launching the new-and-improved version of CS50x on edx.org and CS50’s YouTube. A little sneak peek below!

Happy holidays from Professor @davidjmalan.bsky.social and CS50’s whole team here in Cambridge. 🎁 Stay tuned for release of CS50x 2026 on January 1, 2026. youtube.com/shorts/8XuW8...

Tune in to CS50’s YouTube channel to watch interviews from the CS50 Fair. You’ll see students at Harvard present their final projects. And you'll perhaps be inspired for a project of your own! 💫

This is CS50x 2026 with Professor David J. Malan, CS50's (free) introduction to the intellectual enterprises of computer science and the art of programming, now with artificial intelligence (AI). 🦆 Full season available on edX on January 1, 2026. Register at cs50.edx.org.

Live from Harvard University at 1:30pm EST with Professor David J. Malan, this is CS50's last lecture this year. Open to anyone online. This lecture will become part of CS50x 2026 on edX on January 1, 2026. On YouTube at youtube.com/live/NcBMUE1.... On Zoom at cs50.zoom.us/meeting/regi....

Check out this podcast with Professor @davidjmalan.bsky.social and @freecodecamp.bsky.social teacher and founder @quincy.bsky.social, where they talk about how CS50 got its start, the impact of AI on programming, and the future of education. youtu.be/ZK6XWSCCgPQ?...

Live from Harvard University at 1:30pm EST, this is Week 9 of CS50 on Flask. Open to anyone online. This lecture will become part of CS50x 2026 on edX on January 1, 2026. On YouTube at www.youtube.com/live/F8w1K3C.... On Zoom at cs50.zoom.us/meeting/regi....

Live from Harvard University at 1:30pm EST, this is Week 8 of CS50 on HTML, CSS, JavaScript. Open to anyone online. This lecture will become part of CS50x 2026 on edX on January 1, 2026. On YouTube at youtube.com/live/gPCuN4W.... On Zoom at cs50.zoom.us/meeting/regi....

Live from Harvard University at 12pm EDT, this is CS50's lecture on AI. Open to anyone online. This lecture will become part of CS50x 2026 on edX on January 1, 2026. On YouTube at youtube.com/live/yD1Y1ch.... On Zoom at cs50.zoom.us/meeting/regi....

Live from Harvard University at 1:30pm EDT, this is Week 7 of CS50 on SQL and more. Open to anyone online. This lecture will become part of CS50x 2026 on edX on January 1, 2026. On YouTube at youtube.com/live/kaA8eKB.... On Zoom at cs50.zoom.us/meeting/regi....

Live from Harvard University at 1:30pm EDT, this is Week 6 of CS50 on #Python. Open to anyone online. To attend in person some day, see cs50.ly/attend. On Zoom at cs50.zoom.us/meeting/regi.... On YouTube at youtube.com/live/KV2Nib7....

🧩 The first-ever CS50x Puzzle Day in London is this Friday, October 10, 2025 at 5:00 PM British Summer Time, hosted at Meta by Professor David J. Malan, Professor Daniel Wilson, Professor Tom Crawford from Oxford, and CS50's alumni and friends at Meta.

Live from Harvard University at 1:30pm EDT, this is Week 5 of CS50 on data structures and more. Open to anyone online. This lecture will become part of CS50x 2026 on edX on January 1, 2026. On YouTube at www.youtube.com/live/Sca41aX.... On Zoom at cs50.zoom.us/meeting/regi....

Live from Harvard University, this is Week 4 of CS50 (on memory and more). Open to anyone online. This lecture will become part of CS50x 2026 on edX on January 1, 2026. On Zoom at cs50.zoom.us/meeting/regi.... On YouTube at youtube.com/live/aQFbviJ....

Live from Harvard University at 1:30pm EDT, this is Week 3 of CS50 on algorithms. Open to anyone online. (Or attend in person some day, per cs50.ly/attend.) Watch on YouTube at youtube.com/live/4eN3_kb.... Register for Zoom at cs50.zoom.us/meeting/regi....

CS50 is back in the United Kingdom! Join us at Meta in London on Friday, October 10, 2025, for a CS50x Puzzle Day with Oxford Lifelong Learning, University of Oxford.

Hello, world! CS50 will again be offered at University of Oxford in Michaelmas and Hilary terms. To attend online, register at lifelong-learning.ox.ac.uk/courses/intr....

Live from Harvard University at 1:30pm EDT, this is Week 2 of CS50 on arrays and more. Open to anyone online. (Or attend in person some day, per cs50.ly/attend.) On YouTube at youtube.com/live/2Z-UFxZ.... On Zoom at cs50.zoom.us/meeting/regi....

Live from Harvard University at 1:30pm EDT, this is Week 1 of CS50 on C. Open to anyone online. On YouTube at youtube.com/live/2Lg0W1_.... On Zoom at cs50.zoom.us/meeting/regi.... Or, to attend in person some day, see cs50.ly/attend.

Hello, world! CS50's lectures in Sanders Theatre at Harvard University are open to the public, September 2025 – November 2025. Fall 2025's lectures will become part of CS50x 2026 on edX. To attend in person, visit cs50.ly/attend. To watch online instead, register at cs50.ly/watch. Schedule ↓

Last week, we hosted this year's CS50 Educator Workshop. 🌎 Over two days, educators explored CS50’s teaching resources, heard from CS50’s own David J. Malan about the course's pedagogical decisions, and shared strategies for teaching computer science! ✏️

This was the first-ever CS50 Hackathon at Meta in London 🇬🇧, with workshops on AI, Llama, Wearables, and Number Games by CS50’s own @davidjmalan.bsky.social and Rongxin Liu, Oxford’s own @tomrocksmaths.bsky.social, et al. 💻

Last month, CS50’s team got together to say goodbye to Yuliia and Vlad. For the last two years, Yuliia has been CS50’s preceptor, helping manage CS50 both on campus and off, while Vlad worked on CS50's social media and video production. Wishing them all the best in their next chapters! 🚀

Meet Zeyad Belal, from Port Said, Egypt. For his #CS50FinalProject, he built a classic memory card game that challenges players to match pairs using logic and concentration. 🧩 youtu.be/YFEQVEk6XYM

Q: Will my real name or username appear on my certificate? A: For CS50 Certificates, we will ask you what name you wish to appear. For edX’s Verified Certificates, the name associated with your edX account will appear on your verified certificate. #FAQ50

CS50 is back in the United Kingdom! Join us in London on Friday, June 20, 2025, for a CS50 Hackathon with the University of Oxford and Meta, with Professor David J. Malan from Harvard, Professor Daniel Wilson from Oxford, and Professor Tom Crawford from Oxford. www.eventbrite.com/e/cs50-hacka...

In this #CS50seminar, CS50’s Teaching Fellow Ravi Rajamani introduces you to CXR Foundation, an open-source model from Google Health AI for analyzing chest X-rays. 🩻 Learn how to run your first inferences, explore real-world use cases, and hear about AI’s role in modern medical imaging.

"If you asked me about one of my most memorable moments at Harvard University, I would still immediately think of my very first lecture here. It happened to be CS50 – Introduction to Computer Science, held in the iconic Sanders Theatre...", by Inno '25. college.harvard.edu/.../my-favor...

Do you know about the CS50 Manual?📘 A simplified version of C's "man pages" for functions frequently used in CS50. Whether you're just getting started or need a quick reference, it’s here to help. manual.cs50.io

Did you get a free certificate prior and now want to upgrade to a verified one? If so, log into your edX account and purchase a verified certificate for that course. Then email your edX receipt to [email protected] with the hashtag #upgrade in the subject line.

Watch Professor David J. Malan and CS50’s own Yuliia Zhukovets answer your questions during these Office Hours recorded at the CS50’s office. 🏫 youtu.be/w4dNGeCwgVY

Join us for a Q&A with Professor David J. Malan and CS50’s own Yuliia Zhukovets this Friday, May 16, at 11:30 AM EDT on CS50’s YouTube. Comment with your most pressing questions below! 👇

This was Visitas 2025, a weekend during which future Harvard students visited campus and attended some of the exciting courses in store (CS50 among them!). 📸

Q: GitHub has disabled my account. What should I do? A: Best to visit cs50.ly/github in incognito mode (i.e., private mode, so that you're logged out) and contact GitHub directly! #FAQ50

Check out this #CS50seminar led by CS50’s Teaching Fellow Kamryn Ohly, where she walks you through the basics of iOS development using Xcode and Swift — including how to build your own Buzzfeed-style quiz game! Explore APIs, AR, and even launching your app to the App Store. youtu.be/Bq-9dZp_Asw

Here’s more pictures from Rongxin’s Birthday Lunch! Rongxin is the architect of CS50's AI-based rubber duck. 🦆

Check out this #CS50FinalProject by Tina Bruce from Stockholm, Sweden. “BookIt” is a web booking app made with Flask, Python, JavaScript, SQLite, HTML, and CSS. 🏨 youtu.be/_Y-PANaLhqk

Bonus: some of our favorite memes shared by CS50x Puzzle Day's participants this year! 😄

Congrats to everyone who took part in this year’s CS50x Puzzle Day. 🧩 Here are some stats! Which was your favorite? Check out the solutions at cs50.medium.com and see you next year!

CS50x Puzzle Day starts on Friday, April 4, and ends on Monday, April 7! 🧩 Make sure to register at cs50.ly/register. Good luck with this year's puzzles!

As a part of a global campaign to make people more aware of computer science education, CS50 has installed a few (huge!) rubber duck debuggers in some of the world's biggest cities. Comment if there’s one in your city! 🦆

Hello, world! CS50x Puzzle Day is back. Starts anytime after 00:00 on Friday, April 4, and ends anytime before 23:59 on Monday, April 7, in your own time zone. Register at cs50.ly/register. www.youtube.com/watch?v=wTKG... #education #community #puzzles

This is David J. Muppet. "Draw this in the style of Muppets," a prompt to OpenAI's GPT‑4o model.

Q: Where can I find the gradebook for CS50x? A: CS50x uses our own gradebook at cs50.me/cs50x. If you’ve never visited that link before, you’ll need to click the link to “enroll,” which really just enables your gradebook access! An edX account is required. #FAQ50

Are you interested in the intersection of AI and medicine? Check out this #CS50seminar by Google’s own Andrew Sellegren (who took CS50 his senior year in college!), where he talks about how AI and medical imaging can be used for diagnosis and prediction in the medical field. youtu.be/QnDuVI8YO1I

This was Julianna’s and Max’s birthday lunch! 🎉 Julianna is a CS50 teaching fellow, helping on-campus students during fall semesters and developing tools for better learning like the AI duck debugger. 🦆 And Max, part of the team for 7 years, helps bring you the best-looking content you expect! 🎥

"We present the results of multi-year collaborations among Harvard University, Yale University, and Miami Dade College in which students on all three campuses took the same introductory course in computer science…” Read the full study: cs.harvard.edu/malan/public....

This week, CS50’s team got together for Vlad’s birthday lunch! 🎂 Vlad manages CS50's social media and works with CS50’s production team.

Are you already using CS50.dev? 💻 It is a browser-based version of VS Code in the cloud designed for students and teachers working on programing projects, provided by Harvard’s CS50, implemented atop GitHub Codespaces. You can try it for free at cs50.dev.

Looking to get inspired for your own #CS50FinalProject? 💫 We’ll occasionally showcase projects by classmates! Little Penguin, made by Carl Andrei from The Philippines is a beautiful platformer built on Unity, full of fun visuals and cute ways to play as a penguin! 🐧 youtu.be/4nG7E4brBSs