The "small codebase" claim hinges on the fact that you're not counting the lines of code in nginx, leveldb, and other external software that are glued together to make this system. Those systems may reflect the years of battle-hardening you seek.
So, it may be more reliable than you think by virtue of that selective counting of codebase lines.
So, it may be more reliable than you think by virtue of that selective counting of codebase lines.