CS50
@cs50.harvard.edu
Harvard University’s introduction to the intellectual enterprises of computer science and the art of programming, taught by @davidjmalan.bsky.social.
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....
On YouTube at www.youtube.com/live/F8w1K3C....
On Zoom at cs50.zoom.us/meeting/regi....
November 10, 2025 at 3:02 PM
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....
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....
On YouTube at youtube.com/live/gPCuN4W....
On Zoom at cs50.zoom.us/meeting/regi....
November 3, 2025 at 2:12 PM
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....
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....
On YouTube at youtube.com/live/yD1Y1ch....
On Zoom at cs50.zoom.us/meeting/regi....
October 24, 2025 at 12:52 PM
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....
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....
On YouTube at youtube.com/live/kaA8eKB....
On Zoom at cs50.zoom.us/meeting/regi....
October 20, 2025 at 1:02 PM
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....
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....
On Zoom at cs50.zoom.us/meeting/regi....
On YouTube at youtube.com/live/KV2Nib7....
October 8, 2025 at 1:06 PM
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....
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.
October 6, 2025 at 1:26 PM
🧩 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....
On YouTube at www.youtube.com/live/Sca41aX....
On Zoom at cs50.zoom.us/meeting/regi....
October 6, 2025 at 1:10 PM
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....
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....
On Zoom at cs50.zoom.us/meeting/regi....
On YouTube at youtube.com/live/aQFbviJ....
September 29, 2025 at 1:07 PM
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....
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....
Watch on YouTube at youtube.com/live/4eN3_kb....
Register for Zoom at cs50.zoom.us/meeting/regi....
September 22, 2025 at 1:56 PM
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....
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.
September 18, 2025 at 1:11 PM
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....
CS50: An Introduction to Computer Science
Based on Harvard's famed introductory course in computer science, CS50 is now available at Oxford. This course teaches you how to solve problems, both with and without code, with an emphasis on correc...
lifelong-learning.ox.ac.uk
September 17, 2025 at 12:39 PM
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....
On YouTube at youtube.com/live/2Z-UFxZ....
On Zoom at cs50.zoom.us/meeting/regi....
September 15, 2025 at 1:06 PM
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....
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.
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.
September 8, 2025 at 1:21 PM
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.
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 ↓
To attend in person, visit cs50.ly/attend.
To watch online instead, register at cs50.ly/watch.
Schedule ↓
August 18, 2025 at 7:09 PM
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 ↓
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! ✏️
July 25, 2025 at 12:24 PM
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. 💻
July 17, 2025 at 4:22 PM
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! 🚀
July 11, 2025 at 2:56 PM
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
youtu.be/YFEQVEk6XYM
Memory Game Google Chrome 2023 01 04 21 59 40
YouTube video by zeyad belal
youtu.be
June 10, 2025 at 2:27 PM
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
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
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
June 5, 2025 at 2:25 PM
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
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...
www.eventbrite.com/e/cs50-hacka...
June 2, 2025 at 2:34 PM
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...
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.
Getting Started with AI for Medical Imaging: Exploring CXR Foundation from Google Health AI
YouTube video by CS50
youtu.be
May 30, 2025 at 2:15 PM
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...
college.harvard.edu/.../my-favor...
May 27, 2025 at 2:25 PM
"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...
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
manual.cs50.io
May 22, 2025 at 1:26 PM
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
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.
May 20, 2025 at 2:38 PM
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
youtu.be/w4dNGeCwgVY
Office Hours with Professor Malan and Yuliia Zhukovets @ CS50 Office
YouTube video by CS50
youtu.be
May 16, 2025 at 4:38 PM
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
youtu.be/w4dNGeCwgVY