Writing a geocoder is hard because they combine natural language processing (i.e. address parsing, an exceptionally hard problem) with the need to search through a very large dataset, typically 300-500GB but sometimes more. Doing that for each query generally requires using ElasticSearch, which doesn't respond well to being run on a VPS with 512MB of RAM. If you're not interested in this subject, there are lots of other posts on this site you can go read about.

Edit: In addition to the RAM requirements, you need a persistent volume containing the entire index attached to each serving instance, which is a real bummer when you want to scale horizontally.

> When you write like this it sounds very unprofessional. Also you are basically saying "this is really expensive, unless it isn't".

Likewise actually, it's kind of unprofessional to respond in this way to somebody's personal writing style for a writeup on her personal blog about a personal project. Go read some other Show HN thread, there's lots of genuinely cool stuff here, no need to pick on someone for writing in a way you disapprove of.