Connect Backblaze B2 to WordPress

1. 1

   Create the bucket

   Sign in to Backblaze, go to B2 Cloud Storage > Buckets and select Create a Bucket.

   Name: unique across all of Backblaze, at least 6 characters, letters, numbers and hyphens.

   Files in Bucket: choose Public so visitors can see your images (see the next steps).

   After creating it, copy the Endpoint shown on the bucket (s3.<region>.backblazeb2.com). The part between "s3." and ".backblazeb2.com" is the region to enter in Offloft.

   Bucket name

   my-site-media

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   Open Backblaze B2's consoleBackblaze B2's documentation

2. 2

   Create an application key for this bucket

   Go to Application Keys and select Add a New Application Key. The master application key does not work with the S3 API, so a new key is needed.

   Allow access to Bucket(s): choose "my-site-media". Type of Access: choose Read and Write.

   Select Create New Key. In Offloft, the keyID is the Access Key ID and the applicationKey is the Secret Access Key. Backblaze shows the applicationKey only once.

   Open Backblaze B2's consoleBackblaze B2's documentation

3. 3

   Let visitors read the files

   Backblaze makes files readable per bucket, not per file. Open Buckets, select Bucket Settings on "my-site-media" and set Files in Bucket to Public.

   If Public is not offered, Backblaze first asks you to verify your email address and to have a payment history on the account.

   Open Backblaze B2's consoleBackblaze B2's documentation

4. 4

   Serve files from your own domain through CloudflareOptional

   Find your bucket's download host: open any file in the bucket and look at its Friendly URL, for example https://f004.backblazeb2.com/file/my-site-media/….

   In Cloudflare DNS, add a CNAME record for media.yoursite.com pointing to that host (f00x.backblazeb2.com), with the proxy (orange cloud) on. Set SSL/TLS to Full (strict).

   Under Rules, create a URL Rewrite Rule: when the hostname equals media.yoursite.com, rewrite the path dynamically with the expression below, so visitors do not see /file/my-site-media in addresses.

   In Offloft, use https://media.yoursite.com as the delivery address.

   Rewrite expression

   concat("/file/my-site-media", http.request.uri.path)

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   Delivery address

   https://media.yoursite.com

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   Open Backblaze B2's consoleBackblaze B2's documentation

5. 5

   Allow your site to read files (CORS)Optional

   This step is optional. Images on your pages load without it. You need it only when your site's own scripts read files from storage, for example image editors, web fonts or 3D viewers. The rule below lets only your site read files, and only read them.

   Open Bucket Settings on "my-site-media", go to CORS Rules, choose Share everything in this bucket with one origin, enter your site's address below and apply the rule to the S3 Compatible API.

   Origin

   https://yoursite.com

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   Open Backblaze B2's consoleBackblaze B2's documentation

6. 6

   Run the connection test and the delivery check

   In Offloft, paste your values and run the connection test. It checks your credentials, finds the bucket, uploads a test file, reads it back and deletes it. The delivery check then loads a small test image from your public address. Offloft serves nothing from the cloud until both pass.

The steps above match the guide inside the plugin, checked against Backblaze B2's documentation on 2026-10-26. Example values are shown here; the plugin fills in your own.