Productivity

Neroidea

Free browser tools and games — HEIC converter, seller fee calculators, daily puzzles.

Neroidea

About Neroidea

Neroidea is a free browser toolkit that runs entirely client-side — no account, nothing uploaded. Batch HEIC conversion (JPG/PNG/WebP/PDF) with EXIF preserved, seller fee calculators for six marketplaces with 2026 official rates, daily games (Promptle, Math Party, Magic Cube), and a curated gallery of 1,100+ AI artworks with the exact prompts behind them.

Who is Neroidea for?

iPhone users who got HEIC files they cannot open and were about to upload them to a random converter site; marketplace sellers on Amazon, Etsy, eBay, Depop, Poshmark or Mercari doing fee math in a spreadsheet; people who want a two-minute daily puzzle.

How does Neroidea work?

Open neroidea.com, pick a tool (e.g. HEIC converter), drop files or type numbers, download the result. No sign-up, nothing leaves the browser.

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