Updated October 4, 2026
Atsumaru Open-Source Architecture: A Practical Overview
What the public repository says about Atsumaru's stack, local setup, and development workflow.
Atsumaru's architecture is unusual among reader sites: fully self-hosted infrastructure — and, importantly, no longer open source. Here is the practical picture.
Fully self-hosted
"Self-hosted" means the project runs its own infrastructure rather than renting reader widgets or embedding third-party players. That is what enables the speed: advanced prefetching, direct page serving, and a reader tuned end-to-end. It is also expensive to operate — one reason the developer cites for keeping the code closed.
No longer open source — the history
Atsumaru launched open source in 2022. Over time, the developer found almost nobody contributed code — while many wanted instructions to deploy for-profit copies. So the code was closed; the old 1.0 code remains available on the project's dev branch for the curious, but 2.0 and beyond are proprietary.
What this means for you
- Do not expect a GitHub repo to self-host from — there is no current open-source release to deploy.
- "Self-hosted" describes their infra, not yours — you read on atsu.moe; you cannot run your own Atsumaru from public code.
- Guides calling it open-source are outdated — now you know the real story.
The PWA angle
For mobile, Atsumaru ships as a progressive web app — installed from the browser, updating automatically, no app store involved. See using the web reader. Back to the Atsumaru overview.