Duplicate Finder

A self-hosted Docker web app that scans a photo/video library, detects duplicates using four methods, and lets you review them in a gallery UI. No files are ever moved, renamed, or deleted — all decisions are recorded in SQLite only.

Quick start

# 1. Edit docker-compose.yml — set your photos volume path
# 2. Build and run
docker compose up -d --build
# 3. Open http://localhost:8765
# 4. Enter folder path in UI and click Scan

Volume mounts

Container path	Purpose
/photos	Your photo library — mounted read-only
/data	SQLite database persistence

Edit docker-compose.yml to point these at your NAS paths.

Detection methods

Method	Color	Description
SHA-256	Blue	Byte-identical files
Perceptual hash	Purple	Visually similar photos (hamming ≤ 10)
EXIF timestamp + device	Amber	Same camera, same moment
File size + dimensions	Gray	Same size and resolution (low confidence)

Scan modes

Mode	Description
Incremental	Only re-hashes changed/new files. Prior decisions preserved.
New files only	Indexes newly added files. Existing decisions untouched.
Rebuild groups	Re-runs detection on existing index. No re-hashing.
Full reset	Wipes everything and scans from scratch.

Google Takeout

The scanner automatically detects Google Takeout folder structures and reads .json sidecar files to restore correct capture timestamps and original filenames. Takeout files are flagged in the UI.

What "redundant" means

Marking a file redundant only writes to the database. Nothing is moved, renamed, or deleted. This tool produces a decision record only. A separate tool handles file actions.

Tech stack

• Python 3.12, FastAPI, Uvicorn
• SQLite (stdlib sqlite3)
• Pillow, imagehash, pillow-heif
• Vanilla JS single-page frontend
• Docker / docker-compose