Build ATS-ready resumes with your own AI. Your data never leaves your device.
Resume engine
Transform your raw AI output into a high-impact executive resume. Use our precise formatting tools to render metrics-driven bullet points that instantly pass automated screening systems.
Cover letter generator
Generate a highly targeted cover letter tailored directly to a job description. The prompt engine securely links to your local resume data to stack real evidence in your application.
Draft Cover LetterReal-time activity
These numbers reflect real-time activity across the entire Esper Library community.
Resumes built on this site
Cover letters crafted live.
Keep Esper Library independent
There is no subscription and no paywall—everything runs in your browser. Optional tips help cover hosting and ongoing work on prompts, templates, and privacy-first tooling so the project can stay free for everyone.
How BYOAI actually works
Generate the prompt
We analyze the current constraints of ATS systems and generate a highly engineered prompt specifically designed to extract, parse, and optimize your career data.
Bring your own AI
Copy our prompt and paste it directly into the AI you already use, such as ChatGPT, Claude, or Gemini. Let the world's smartest models do the heavy lifting for you.
The local workspace
Bring the perfected text back to Esper Library. Our engine compiles it into a flawless, ATS-optimized PDF document strictly within your browser. No server storage.
The architectural advantage
You supply your preferred AI engine. We supply the high-value prompt architecture. You get premium output without the standard monthly subscription trap.
Total privacy
Your entire career history is stored locally in your browser. We never track, harvest, or store your personal data on external servers.
ATS-optimized
Built specifically to bypass Applicant Tracking Systems. Export your documents instantly into a clean, parsed, standard format.
Why ATS optimization matters
Research shows that resume format and keyword optimization significantly impact your chances of reaching hiring managers.
Average time recruiters spend on the initial resume scan, per eye-tracking research.
JobEase ResearchFrequently asked questions
Is Esper Library a free resume builder?
Yes. Esper Library is completely free. There are no subscription fees, premium tiers, or hidden costs. All features—including the ATS-optimized resume engine, cover letter generator, and formatting tools—are available at no charge.
How does the BYOAI system work?
BYOAI (Bring Your Own AI) means Esper Library provides the prompt architecture and formatting engine, while you supply your own AI to generate content. You copy our engineered prompts into ChatGPT, Claude, Gemini, or any other AI you prefer, generate the output, then paste it back into Esper Library. The platform compiles everything into polished, ATS-safe documents—no proprietary AI required.
Are the documents ATS-optimized?
Yes. All documents built with Esper Library are specifically designed to bypass Applicant Tracking Systems and parse cleanly. The formatting engine produces clean, structured output that ATS software can read accurately, so your resume reaches hiring managers instead of getting filtered out.