How Facebook’s News Feed Works: Architecture, Culture, and Ranking Secrets

Community Introduction: For a startup, a qualified CTO is rare; they need foresight in technology, industry insight, management skills, and high emotional intelligence. This article compiles talks from Qian Chao, a partner at Fengrui Capital and former Facebook engineer, and Xu Wanhong, CTO of Shenzhou Didi and former Facebook engineer, discussing how startups can build engineering culture and the principles behind Facebook’s News Feed.

1. What Do Facebook CTOs Do?

Qian Chao: Worked at Facebook from 2010‑2014 on front‑end mobile development (Facebook Phone, iOS/Android apps, Messenger) and also on PHP back‑end work.

Facebook values both technology and design equally, with an office full of artistic elements designed by Frank Gehry. The company’s inclusive culture is reflected in its rainbow‑styled décor and open‑mind environment, encouraging things like drones or Oculus VR in the office.

Posters in the office serve as internal branding and “political education.” Everyone can contribute designs, and a dedicated room produces the posters.

Transparency is a core principle: there is no strict permission control, and any employee can view MAU, DAU, and detailed metrics on the intranet, reducing management overhead.

The workspace is an open‑plan “internet‑café” style, fostering communication and peer pressure (e.g., being seen if you’re late or playing games). Trust by default is granted, with strong enforcement against leaks.

Typical project staffing: 2‑3 designers, 5‑10 engineers, 2‑3 product managers, working in two‑week sprints. Design precedes development, but continuous interaction occurs throughout.

Code review is mandatory across Facebook, Google, Uber, Airbnb, etc., often using tools like Phabricator (open‑source, customized and localized by the fund) and internal task systems. For CI/CD, Jenkins is common, though Travis CI and Drone are recommended alternatives.

2. How Does Facebook’s News Feed Work?

Xu Wanhong: CTO of Shenzhou Didi, former Facebook engineer.

The News Feed is Facebook’s most important product, serving over 1 billion users, each receiving more than 2 000 stories daily.

Real‑time publishing without missing important stories.

Latency from story creation to delivery is under 1 second, with ranking taking less than 200 ms; data loss is below 1E‑6, relying heavily on system architecture.

Best content is placed at the top to boost user engagement, driven by a ranking system.

System architecture uses both push and pull models; Facebook prefers the pull model to reduce storage overhead.

Ranking assigns scores to stories based on weighted user actions (click, like, comment), with comments receiving higher weight. Machine‑learning models predict the probability of each action for each user, using real‑time feature generation, training, and publishing. Personalization combines generic models with user‑specific data, though full per‑user models are limited by scale.

The feedback loop continuously updates models with real‑time user behavior, improving relevance over time.

Facebook also places high demands on engineers’ technical abilities and provides comprehensive training, including the powerful design tool Origami for interactive design and code generation.

This article is reproduced with permission from Fengrui Capital (freesvc). Feel free to discuss.