Problem
Default download filenames are garbage — download (47).pdf, IMG_2241.png.
A folder of those is a hostile place to search through weeks later.
Approach
A Chrome extension that catches the download and renames it from a rule set:
smart placeholders ({domain}, {date}, {time}, {originalFilename},
{category}, {extension}), custom regex placeholders with text and counter
types, and a floating preview that shows the resolved name before the file
is saved.
Stack
Plain Manifest V3: vanilla JavaScript, no framework, no build step. HTML + CSS for the options UI, a small placeholder DSL, and safe filename sanitization. A few hundred lines — easier to audit than to bundle.
What shipped
Published on the Chrome Web Store (v1.3.0): drag-and-drop placeholder ordering, automatic file categorization, custom separators, and the live preview panel.
What’s next
Cross-browser support and an exportable rule pack so teams can share conventions.