Converter
JPG to PDF
FreeCombines images into a single PDF, with control over page size, order and margins.
Add to Chrome
Focused browser tools since 2019
Sharp tools. No fluff, no accounts.
Kobaltstack makes small browser extensions, each built to solve exactly one problem. No sign-ups, no tracking, no bloat.
3
Tools, each doing one job
100K+
People use a Kobaltstack tool every week
0
Accounts, sign-ups or passwords required
The stack
Three tools. Zero friction.
Each one is a production extension that people use every day. Click through to install it from the Chrome Web Store.
Security
Authenticator
FreeTime-based 2FA codes that live in your browser: encrypted, portable and offline-first.
Add to Chrome
Converter
MP4 to MP3
from $5Extracts clean audio from any MP4 right on your machine. Files never leave your computer.
Add to Chrome
About
Do one thing. Do it exceptionally well.
We are a small independent studio that has been shipping utility extensions since 2019. Today more than 100,000 people reach for a Kobaltstack tool every week — quietly, and without ever signing up.
One job per tool
Each product answers a single question. No settings panels for things you do not need.
Your data stays local
Conversion and processing happen in your browser. Your files never touch our servers.
No account wall
Install, click, done. No logins, no email verification, no cookie pop-ups.
Built to last
We keep improving the same tools instead of inventing new ones every quarter.
Contact
Get in touch
A question, a partnership idea or feedback about one of our tools? Write to us — we answer every message, usually within two business days.