Integration · OneDrive
Back up email to OneDrive — automatically.
Forward any email to your private InboxBucket address and the original .eml lands in a folder in your own OneDrive — headers, body, and attachments intact. Ideal if you already live in Outlook and Microsoft 365.
Free plan available · No credit card required
- From:
- Acme Billing <[email protected]>
- To:
- [email protected]
- Subject:
- Invoice #4471 — June services
- Files:
- invoice-4471.pdf
/Apps/InboxBucket/2026/07/0713__invoice-4471__acme-billing.eml
✓ stored · 84 KB · original MIME
Why back up to OneDrive
A copy that outlives the account.
Your mailbox is one lock away
A flagged sign-in or a lapsed subscription can put your Outlook mailbox out of reach — and every receipt and contract with it. A standing .eml archive doesn't depend on getting back in.
Files, not a locked export
Not a PST you'll wrestle into an app. Each email is a single .eml in your OneDrive — browsable, searchable, and openable in Outlook or anything else.
It runs without you
One forwarding rule in Outlook and new mail archives itself from then on — no scheduled export to remember, no app left running on a PC.
How it works
Three steps, then it runs itself.
Connect OneDrive
Sign in with your Microsoft account and approve one thing: a single app folder InboxBucket creates in your OneDrive. It's Microsoft's most limited file permission — nothing else in your OneDrive is exposed.
Get your address
You receive a private inbound address that exists only to receive your mail:
[email protected]Forward anything
Forward one message by hand, or set an auto-forward rule in Outlook so every email backs itself up. Seconds later, the original .eml is sitting in your OneDrive.
The access we ask for
One app folder. Nothing else.
InboxBucket asks Microsoft for a single permission: access to one app folder it creates in your OneDrive. That's the most limited file access Microsoft offers — it can't see, open, or change anything outside that folder. The rest of your OneDrive, and everything in Microsoft 365, stays private.
We're the pipe, not the vault. Mail only passes through us on its way to your OneDrive; what we keep is the metadata behind your dashboard — sender, subject, date, status — never the messages. Revoke access whenever you like from your Microsoft account, and the .eml files already saved stay put.
- Creates and manages one app folder in your OneDrive
- No access to the rest of your OneDrive or Microsoft 365 files
- Can't read, edit, or delete anything it didn't create
- Revocable anytime — your saved .eml files remain
What lands in your OneDrive
Sorted, dated, and yours.
InboxBucket files each message into a dated folder tree inside its app folder, named so you can find anything at a glance. Each file is a complete .eml — the original message, not a rendering or an export.
A note on space: OneDrive's free tier is 5 GB, and a Microsoft 365 subscription raises it to 1 TB — ample for years of mail. Since each .eml is just text plus its attachments, a large archive is usually a small slice of that. Prefer somewhere else? Point InboxBucket at Google Drive, Dropbox, or S3 instead.
OneDrive/
└── Apps/
└── InboxBucket/
└── 2026/
└── 07/
├── 0713__invoice-4471__acme-billing.eml
├── 0711__signed-contract__legal.eml
└── 0708__flight-receipt__airline.emlThe details
Built like a backup should be.
The original message, nothing rewritten
Every email lands as a .eml — the raw RFC 822 message with headers, body, and attachments in one file. Open it in Outlook, Apple Mail, Thunderbird, or a text editor, with no conversion, ever.
Attachments land intact
Files are streamed to OneDrive in chunks, so a 40 MB signed contract arrives whole, attached to the message it came with — past any single-request size limit.
Stored once, however it arrives
People double-forward and mail servers retry. We deduplicate on Message-ID, so each message is written to your OneDrive exactly once.
Only senders you approve
A per-sender allowlist keeps a scraped address from filling your OneDrive with spam — only mail from senders you've approved is ever archived.
Loud on failure, never silent
An expired token or a Graph API hiccup queues the upload and retries it, with status visible in your dashboard until it lands — and a clear prompt if the connection needs re-authorizing.
Findable without folder-digging
Sender, subject, date, and status are indexed for every message, so you search your archive from the dashboard instead of clicking through OneDrive.
Using Outlook or Microsoft 365?
OneDrive pairs naturally with Outlook. Set a forwarding rule in Outlook.com or the Outlook app that points at your InboxBucket address, and every message archives itself to OneDrive.
FAQ
OneDrive backup, answered.
Where are my emails stored?
In your own OneDrive. InboxBucket passes each message through only long enough to parse and deliver it, then writes the original .eml to the app folder it created in your OneDrive. The archived copy lives in your account, not ours — we keep only the metadata (sender, subject, date, status) that powers your searchable dashboard.
What OneDrive permissions does InboxBucket need?
Access to a single app folder it creates — the most limited file permission Microsoft offers. InboxBucket cannot see, open, or change anything outside that folder; the rest of your OneDrive and Microsoft 365 files stay private. You can revoke access anytime from your Microsoft account security settings, and the files already saved stay where they are.
Does this work with OneDrive for Business and Microsoft 365?
Yes. It works with both a personal OneDrive (a personal Microsoft account) and OneDrive for Business under a Microsoft 365 work or school account — the .eml files land in your OneDrive either way. Work and school accounts may require the usual one-time admin consent, depending on how your organization configures third-party apps.
How much OneDrive storage do I need?
OneDrive's free tier is 5 GB, and a Microsoft 365 subscription raises that to 1 TB — ample for years of mail. Each .eml is just text plus its attachments, so a large archive is usually a small slice of your quota. If you'd rather not use OneDrive space at all, point InboxBucket at Google Drive, Dropbox, or S3 instead.
How do I back up Outlook email to OneDrive automatically?
Connect OneDrive, then add your InboxBucket address as a forwarding rule in Outlook.com or the Outlook app and confirm it. From then on, matching mail is archived to your OneDrive automatically. You can scope the rule so only the mail you choose — receipts, contracts, specific senders — is forwarded.
What format are the backups in?
Every email is stored as a .eml file — the standard RFC 822 message exactly as it arrived, with headers, body, and attachments in one portable file. No proprietary format and nothing to export later; it opens in Outlook or any other mail client, or a plain text editor.
Is OneDrive email backup free?
Yes. The Free plan archives 100 emails a month, with one inbound address and one storage connection, plus full-fidelity .eml backup and searchable history — enough to back up your most important mailbox to OneDrive. The allowance resets on the 1st. The Lifetime plan is a one-time $79 payment with unlimited archived emails, addresses, and storage connections, no subscription.
Can I revoke InboxBucket's access later?
Anytime, from the app permissions in your Microsoft account. Revoking stops new mail from being written, and everything already archived stays in your OneDrive — the files are yours, in a standard format, whether or not InboxBucket is still connected.
Free plan · No credit card
Put your email in your own OneDrive.
Connect OneDrive, get your address, and the next email you forward is saved to a folder you own.
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