Problem: Researchers and grad students accumulate hundreds or thousands of PDF papers with useless filenames like 1706.03762.pdf or download(3).pdf. Manually renaming and tagging them is tedious, and existing tools like Adobe Acrobat do not identify a paper from its content or hash. A HN commenter said it plainly: 'Is there a tool for finding metadata of pdf files based on their hash or content? Like MusicBrainz Picard for identifying and tagging mp3 files.'
Product: PDF Scholar. It brings the MusicBrainz Picard model to academic PDFs. You point it at a folder or drop in files, and it identifies each paper by content extraction (title, authors, DOI, arXiv ID) and file hash, then queries scholarly metadata sources to confirm and enrich. It renames files by a template you choose (for example Author-Year-Title) and writes clean embedded PDF metadata.
Solution mechanics: Extract text and existing PDF tags, match against known identifiers, fall back to fuzzy title/author matching, and use a hash lookup so a re-download of the same paper resolves instantly. Batch operations handle large libraries in one pass.
MVP: A desktop or local app that scans a folder, extracts title/author/DOI from PDF content, looks up canonical metadata, previews proposed renames, and applies them plus embedded metadata. Start with arXiv and DOI-resolvable papers since those give the cleanest matches.
Revenue: One-time license or low monthly SaaS for individuals, with a higher tier for larger libraries and citation export. Comparables in the indie SaaS range (Rezi ~$2580/mo MRR, Kibu ~$2343/mo MRR, Kitze ~$2233 last 30d) suggest a solo-scale but real revenue ceiling for a focused tool.
GTM: Answer the exact HN and StackExchange threads where people ask for this, publish an open comparison to manual Acrobat workflows, and post in grad student and academic subreddits.
Growth loops: Shared rename templates and a public metadata match cache mean each user's corrections improve identification for everyone, and clean filenames get shared in labs, pulling in colleagues.