Liner is a freemium AI search engine and research assistant from Seoul-based Liner Corp. that answers questions with line-by-line source citations, aimed at students, researchers, and professionals who need to verify where an answer came from. It combines an ad-supported free plan with paid Pro and Max subscriptions that unlock access to several major third-party AI models.
What it is
Liner (liner.com, formerly at getliner.com) is positioned as an AI-powered search and research tool built for people who need traceable answers rather than a plain summary. Liner states that "every answer comes from a reputable source" and that users can "follow each source to check them yourself." Its target audience, per the vendor's own framing and independent reviews, is students, researchers, and professionals doing verification-heavy work such as literature review or fact-checking, rather than casual browsing.
How it cites sources
Liner uses inline, line-by-line source citations: independent review site Unite.AI describes it as generating "credible answers with line-by-line source citations to easily verify information," and Liner's own search page states that "every answer comes from a reputable source." This makes it straightforward to trace a specific sentence of an answer back to the web page it came from, rather than only seeing a general source list at the end of a response.
Pricing and access
Liner is freemium. The free plan is listed at $0.00 and includes "Unlimited Advanced Search," though it is ad-supported ("Answers with ads"). The paid Pro plan starts at $14.99 per month when billed annually (the standalone monthly price is $17.99/month); Pro adds access to major third-party AI models, including OpenAI's ChatGPT (o4-mini, GPT-4.1), Google's Gemini (2.5 Pro/Flash), and Anthropic's Claude (4 Opus/Sonnet), alongside Liner's own proprietary Pro models. A higher Max tier also exists per the vendor's pricing page.
Privacy and data use
Liner may use data provided by users to train its internally developed models, but it offers an opt-out: deactivating the "history" and "learning" items in account settings stops new data from being used for model training, per Liner's privacy policy. On hosting, Liner's privacy policy documents overseas data transfers to US-based infrastructure — Google Cloud Platform and Amazon Web Services for cloud hosting, and OpenAI, Anthropic, and Google as AI processors — with no EU-hosting option documented; the policy also states that refusing this overseas transfer means you cannot use the Liner service, so EU users should review the transfer terms before signing up.
Who it's for
Liner fits students, researchers, and professionals who want AI answers they can verify sentence-by-sentence, and who may already want access to multiple frontier AI models (ChatGPT, Gemini, Claude) inside one subscription rather than paying for each separately. Casual users who just want a free, ad-supported search-and-cite tool can also use the free plan, but anyone handling EU personal data under GDPR should note that Liner's documented infrastructure and AI processing all sit in the US, with no EU-hosting alternative currently published.