Connect Backblaze B2

Last updated: November 7, 2026

BucketWorx works with Backblaze B2 through its S3-compatible API, with settings made for B2. You need three things from Backblaze: a key ID, an application key, and the region in your bucket's endpoint.

What you need from Backblaze

1. An application key. In the Backblaze web console, under B2 Cloud Storage, open Application Keys and click Add a New Application Key. Give it a name, choose All buckets or one bucket in Allow Access to Bucket(s), and click Create New Key. Backblaze shows the applicationKey only once, so copy it and the keyID straight away.
2. Your region. On the Buckets page, each bucket shows its endpoint, such as s3.us-west-004.backblazeb2.com. The region is the part after s3.: us-west-004 there.

A key for one bucket can't list your buckets unless you also tick Allow List All Bucket Names when you create it. Without it, BucketWorx still works: see the last of the common problems below.

Add the account in BucketWorx

1. Click Add account, in the middle of the first-launch window or in the sidebar.
2. Open the Provider drop-down and choose Backblaze B2. BucketWorx fills in the settings B2 needs.
3. Type a name you will recognise, such as "B2 backups".
4. Type the region, for example us-west-004. BucketWorx fills in the endpoint from it.
5. Paste the keyID as the access key ID and the applicationKey as the secret access key.
6. Press Test connection. Within about ten seconds it says "Connected. Found N buckets.", or tells you what is wrong.
7. Press Save. The account appears in the sidebar. Click it to see its buckets.

Your secret is kept in your operating system's keychain (Windows Credential Manager, the macOS Keychain, or the Secret Service on Linux), never in BucketWorx's settings file or its logs.

What's different on B2

We run BucketWorx's full test suite against B2. This is what we found, and what BucketWorx does about it. The provider notes compare every provider.

• Every bucket keeps old versions. B2 keeps them whether you ask or not, so you can always restore an earlier version or undelete a file. Moves and renames count on that: if a lifecycle rule removes old versions, BucketWorx stops and says so.
• No conditional writes. B2 refuses "only if it's still the file you chose", so BucketWorx looks at the destination just before each write. Because B2 keeps the old version, nothing is lost even if someone else writes in that moment.
• File dates carry over. BucketWorx stores each file's modification time the way B2 expects (src_last_modified_millis), so the Backblaze web console and the B2 command line show it too.
• Daily caps on the free tier. When you reach one, B2 refuses downloads or requests until the next day. BucketWorx says that's what happened, instead of showing it as a permissions problem.
• No tags, no website redirects, and no tabs or line breaks in file names. BucketWorx doesn't offer what B2 can't keep.
• New buckets go where your key is. B2 doesn't take a location for a new bucket, so BucketWorx doesn't ask for one.

Common problems

• "Couldn't reach the server" or a wrong-region error. Check the region against your bucket's endpoint. It's the full name, such as us-west-004, not just us-west.
• The key is refused. Make sure you pasted the applicationKey, not the keyID, as the secret. If you lost the applicationKey, create a new key: Backblaze can't show it again.
• Downloads fail partway through the day. You may have reached a daily cap. BucketWorx says so; raise the cap in the Backblaze console or wait until the next day.
• The key can't list buckets. Type the bucket names into the account's Bucket names field, or create a key with Allow List All Bucket Names ticked.

What you can do next

• Sync a folder to a B2 bucket, with a preview first.
• Copy files between buckets, including between B2 and Amazon S3, Wasabi or Cloudflare R2.
• Share a file with a link that expires.