Why Khan Academy Switched 500K Lines from Python to Go

Khan Academy, a US nonprofit educational organization, has rewritten its Goliath backend project in Go, replacing the previous Python 2 implementation with more than 500,000 lines of Go code.

When the Goliath project started, no one on the team knew Go, but experiments showed it was a better choice; today all backend and full‑stack engineers write Go, and progressive delivery has allowed the team to cross a major milestone, with over 500,000 lines running in production.

Python 2 reached end‑of‑life in early 2020, prompting a large‑scale migration. Chief software architect Kevin Dangoor noted that moving from Python 2 to 3 is not easy.

The team briefly considered Kotlin but ultimately chose Go because it offers a significant performance advantage over Python 3, extremely fast compilation, and strong editor support, enabling faster iteration.

Engineers report that Go is easy to write and read, praising its error handling, toolchain, and compilation speed. They also expressed a need for generics, especially when writing internal libraries that manipulate slices.

In conclusion, although Go can be more verbose than Python, the organization prefers it for its speed, tooling, and reliable production performance.