Stormbird — Download Gmail to a USB Drive. No Cloud.

⚡ What it does

Your inbox,
offline forever.

Stormbird connects to Gmail via IMAP and downloads every email — inbox, sent, drafts, all mail — as a standard .eml file on your USB drive.

The entire archive is indexed in a local SQLite database. Search across 50,000 emails in under 100ms. No internet required.

Every file gets a SHA-256 checksum at write time. Corruption is detected automatically on every startup.

Stormbird v1.0.0

→Connecting to imap.gmail.com:993

✓ Authenticated: you@gmail.com

→Syncing folder: Inbox

UIDs 1–100 of 24,847 downloaded

Verifying SHA-256 checksums...

✓ 100 files written. All verified.

UIDs 101–200 of 24,847...

✓ 100 files written. All verified.

[Checkpoint saved — UID 200]

→Resumable. Ctrl+C to pause.

⚡ The problem

Your email history is one locked account away from being gone.

Most people assume their email is safe because it's "in Google." It's accessible — which is not the same thing.

RISK 01

Account lockout

Google suspends millions of accounts every year for suspected violations. The appeal process takes weeks — with no guarantee of recovery. If your account is your only copy, you have no access during that entire period. Possibly never again.

RISK 02

Gmail Takeout isn't a backup

Takeout is a one-time snapshot. Every email you receive after export is unprotected. It exports to MBOX — a single giant file with no search. If the download fails halfway through, you start over. And it doesn't keep syncing.

RISK 03

Cloud archiving defeats the point

Paid cloud archive services solve the backup problem by sending your data to yet another company's servers. You've traded one point of failure for another, while paying $5–20/month for the privilege.

⚡

Stormbird is different. It downloads your Gmail to a USB drive you already own. .eml files you can open in any email client. SHA-256 checksums on every file. Resumable sync that never re-downloads the same email. Free, forever.

⚡ Features

Everything you need.
Nothing you don't.

📥IMAP Sync
Downloads your entire Gmail inbox over IMAP. Resumable — saves a UID checkpoint every 100 emails. Never downloads the same email twice. Doesn't mark anything as read.
raw TLS · no packages

🔒

SHA-256 Integrity

Every .eml file gets a cryptographic fingerprint at write time. Spot-check on startup. Full deep scan weekly. Corrupted files flagged automatically.

atomic writes · MANIFEST.txt

🔍

Offline Search

Press Ctrl+F to search across every account and every folder simultaneously. Results in under 100ms. No internet. No query leaves your device.

SQLite local index

⏏

Safe Eject

Flushes the SQLite WAL, closes all connections, then ejects the drive. One click. Never a corrupted archive from an accidental unplug.

PowerShell · diskutil

🗄

NAS Backup

Full or incremental copy to any network path or local folder. Daily or weekly schedule. Set once, runs automatically while Stormbird is open.

set and forget

✉

Compose & Send

Write and send emails from the archive. Persistent outbox queue — messages queue offline and send automatically when internet returns.

SMTP port 587 · STARTTLS

💾

Portable Architecture

Runs from a USB drive. Leaves nothing on the host computer. Plug into any Windows or macOS machine and your full archive is there instantly.

no install required

📊

Process Manager

Every service is monitored with heartbeat tracking. Auto-restarts on failure up to 3 times. Live log console with Ctrl+` shows all activity in real time.

9 states · auto-restart

🎨

Dark & Classic Themes

True-black dark theme with amber accents, and a clean classic light theme. Toggle from Settings or the titlebar. Changes apply instantly.

persists between sessions

⚡ How it works

Up and running in under
five minutes.

The setup wizard walks you through everything on first launch. After that, sync is one click.

STEP 01

Enable Gmail IMAP

Turn on IMAP in Gmail settings under Forwarding and POP/IMAP. Takes 30 seconds.

STEP 02

Generate an App Password

A 16-character code from Google — not your real password. Generate it from myaccount.google.com and revoke it any time.

Security → App Passwords

STEP 03

Extract to your USB drive

Download Stormbird, extract the zip to your USB drive. No installer. Double-click to run.

STEP 04

Click Sync. Walk away.

Stormbird downloads everything. If you close it, sync resumes from the last checkpoint. You'll never download the same email twice.

⚡ Integrity

Every email
has a fingerprint.

SHA-256 checksums are computed at write time and stored in the database. Files are verified against their stored checksum on every startup and in a full deep scan every week.

✓

Atomic writes

Write to .tmp → verify checksum → rename. Never a partial or corrupt file on disk.

✓

Startup spot-check

50 randomly selected files verified every time Stormbird opens. Corruption found before it matters.

✓

MANIFEST.txt

Plain-text checksum file in every year/month folder. Verify your archive with standard tools on any platform, without Stormbird.

✓

Rolling DB snapshots

Last 3 copies of the SQLite database kept automatically. Recover from database corruption independently of the email files.

📁 E:\Stormbird-Data\mail\

└── you@gmail.com\ ├── Inbox\2024\01\ │ ├── a3f8b2c1d4e5f6a7.eml │ ├── b9c2d3e4f5a6b7c8.eml │ └── MANIFEST.txt └── Sent\2024\01\ ├── c1d2e3f4a5b6c7d8.eml └── MANIFEST.txt

SHA-256 · MANIFEST.txt

a3f8b2c1d4e5f6a7.eml

a3f8b2c1d4e5f6a7b9c2d3e4f5a6b7c8
d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6

⚡ Comparison

How Stormbird compares.

Feature	⚡ Stormbird	Gmail Takeout	Thunderbird	Cloud Archiver
Runs from USB drive	✓ Yes	—	✗ No	—
No installation required	✓ Yes	✓ Yes	✗ No	✓ Web
Ongoing sync	✓ Yes	✗ One-time	✓ Yes	✓ Yes
Open .eml format	✓ Yes	⚠ MBOX	✓ Yes	✗ Proprietary
Zero cloud / no data leaves device	✓ Yes	✓ Yes	✓ Yes	✗ No
Built-in offline search	✓ Yes	✗ No	✓ Yes	✓ Yes
SHA-256 checksums	✓ Yes	✗ No	✗ No	⚠ Rarely
Safe USB eject	✓ Yes	—	✗ No	—
Monthly cost	✓ Free	✓ Free	✓ Free	$5–20/mo

⚡ Who it's for

Built for people who take
their data seriously.

🩺

Medical professionals

Patient communications need local retention. Portable across clinics. No cloud exposure for sensitive records.

⚖️

Lawyers & paralegals

Client correspondence is privileged. Off-cloud. Portable archive for case work across offices and courts.

📰

Journalists

Source protection requires no third-party access. Offline-first archive that never touches another server.

🔬

Researchers

Years of research correspondence. Institutional email gets deactivated on exit. Archive it before it's gone.

🔐

Privacy-conscious users

Object to cloud storage on principle. Full data ownership. No telemetry, no analytics, no accounts.

🗃️

Data hoarders

.eml files, SHA-256 checksums, MANIFEST.txt, rolling DB snapshots. Your archive, your terms, forever.

⚡ Technical details

Built properly.

For the technically curious — no shortcuts, no black boxes.

Shell

Electron 29 — cross-platform desktop framework

UI

React 18 + Vite 5 — production-optimised bundle

Database

sql.js (WASM SQLite) — zero native compilation, fully portable

IMAP

Raw Node.js TLS sockets — zero external packages, custom {N} byte-count parser

SMTP

nodemailer — Gmail App Password, port 587, STARTTLS

Storage

Atomic writes — .tmp → verify SHA-256 → rename. Never a corrupt file.

Windows

Windows 10 / 11 x64 — fully supported, primary platform

macOS

macOS 10.15+ Intel — supported. Apple Silicon via Rosetta 2.

⚡ FAQ

Common questions.

Is Stormbird really free?

Yes. Stormbird is free to download and use with no limitations, no trial period, and no premium tier that locks features. If you find it useful, there's an optional Buy Me a Coffee link in Settings → About.

Does my email data leave my device?

Never. Stormbird stores everything on the drive you specify — a USB drive, your PC, or wherever you point it. There is no sync to any cloud, no telemetry, and no analytics. The only outbound connections are to Gmail's IMAP and SMTP servers when you sync or send.

Will it mark my emails as read?

No. Stormbird uses IMAP BODY.PEEK[] which explicitly does not alter the read/unread flag. Your Gmail inbox is completely unchanged by a sync.

What if I unplug the drive during a sync?

Sync stops and the database stays consistent. Stormbird saves a UID checkpoint after every 100 emails. On next launch, it detects the last checkpoint and resumes from there. No emails are lost, no emails are re-downloaded.

Can I read my emails without Stormbird?

Yes. Every email is stored as a standard .eml file in RFC 2822 format. You can open any .eml file with Thunderbird, Apple Mail, Outlook, or any compatible email client on any platform — no lock-in.

How much storage does it use?

The app itself is about 150MB. Email storage depends on your archive size. A typical 10-year Gmail account with moderate use occupies 2–8GB. If you have years of large attachments, plan for more. A 32GB or 64GB USB drive covers most people comfortably.

Does it work with Outlook / Yahoo / iCloud?

Version 1.0.0 supports Gmail only. Support for other standard IMAP providers is planned for v1.1 — the underlying IMAP client is provider-agnostic, it just needs testing with each provider's authentication model.

Is the App Password safe?

Your App Password is stored locally in the SQLite database on your drive — it never leaves your device. App Passwords are separate from your main Google password and can be revoked instantly from myaccount.google.com/apppasswords without affecting anything else.

Download your Gmailto a USB drive.

Your inbox,offline forever.

Your email history is one locked account away from being gone.

Everything you need.Nothing you don't.

Up and running in underfive minutes.

Every emailhas a fingerprint.