I Built a Voice Recorder Extension for Firefox That Keeps All Your Notes Offline

The Problem With Cloud Voice Notes

Every voice note app I tried wanted an account. Then a subscription. Then cloud storage "for sync." And you're trusting a third party with audio recordings that might contain sensitive stuff — medical reminders, personal thoughts, client calls.

I wanted something simpler: record, save, done. No internet required.

What I Built

Voice Notes & Audio Recorder is a Firefox extension that records audio directly in your browser, saves it locally, and never touches a server.

Key things it does:

• Records audio using WebRTC (browser's built-in mic access)
• Stores recordings in IndexedDB — stays in your browser, stays on your machine
• Playback from the extension popup
• No account, no cloud, no phone home

Available on Firefox Add-Ons: https://addons.mozilla.org/firefox/addon/voice-notes-audio-recorder/

Why Firefox?

Firefox has better privacy controls and extension APIs than Chrome. The activeTab permission model means the extension only gets access when you explicitly click it.

Use Cases

I use it for:

• Quick memos when typing would take too long
• Meeting summaries right after a call (before you forget)
• Grocery lists while walking around the kitchen
• Journaling when thinking out loud is easier than writing

The Technical Part

Recording is handled by the MediaRecorder API. Chunks are accumulated via ondataavailable, assembled into a Blob, then stored via IndexedDB. Playback uses a standard audio element with the blob URL. No server, no fetch, no external dependencies.

The entire extension is ~300 lines across 3 files. Simple enough to audit yourself.

Privacy By Design

Audio recordings on your device, controlled by you. That's it. No telemetry, no analytics, no external calls.

If you've been looking for a private voice notes option without the app baggage, give it a try. It's free and open to review.

Firefox Add-Ons page