LINER, founded in 2015 in South Korea, predates most tools in this category by several years and began as a browser-based highlighting and annotation tool for any web page or PDF, not an academic-specific product, before layering AI-powered search and question-answering on top of that annotation foundation more recently.
That highlighter-first origin still shows in the product: annotations and highlights sync across a user's own browsing and reading, general web content included, rather than being scoped only to uploaded academic PDFs the way several younger competitors in this category are. The AI search layer then answers questions grounded in a user's own saved highlights alongside broader search.
A free tier covers standard use, and paid plans start around $12 a month for more features. For someone who wants highlighting and annotation across general web reading, not only academic PDFs, with AI search layered on top of their own saved material, LINER's broader scope and longer operating history address a different need than the academic-only tools surrounding it in this category.
