Esper Library: Free BYOAI Resume Engine – Professional resume and cover letter formatting with your own AI

Summary: Esper Library is a free resume builder and AI cover letter generator that creates ATS-compliant career documents by integrating user-provided AI tools. It processes resumes locally to minimize costs and produce professional PDF layouts.

What it does

Users upload a resume or generate new content, link their preferred AI, and the engine formats the output into a polished, ATS-safe PDF. All data is stored locally to reduce server overhead.

Who it's for

Individuals seeking professional resume and cover letter formatting while using their existing AI subscriptions for content generation.

Why it matters

It avoids redundant AI subscription costs by leveraging users’ own AI tools and ensures documents pass ATS filters with professional formatting.