Backblaze B2 vs OneDrive and SharePoint files (Microsoft Graph)

Backblaze B2

$6.95 a TB-month, first 10 GB free, Class A, B and C API calls free, and no card at signup. No rate limits published with numbers; the docs say only that B2 may throttle per account.

OneDrive and SharePoint files (Microsoft Graph)

One REST surface covers personal OneDrive, work OneDrive and SharePoint libraries, with resumable uploads, sharing links that take an expiry date and per-file Selected permissions. The status page needs JavaScript, an app must be registered and consented to by a person, and the JavaScript client on npm lacks a token-leak fix merged in June 2026.

Backblaze B2

1. Take the region from the key's S3 endpoint (the second label of s3.<region>.backblazeb2.com) and pass it as the SDK region
2. Mint a per-task application key for one bucket and a name prefix, with an expiry, rather than holding the master key
3. Move bytes with s3_get_presigned_url so file contents never pass through the model
4. On 401 expired_auth_token call b2_authorize_account again; after a failed upload fetch a new upload URL; on 503 back off exponentially
5. Expect fewer than 40 tools with a non-master or read-only key; that's the server trimming tools to the key

OneDrive and SharePoint files (Microsoft Graph)

1. Use PUT /content only up to 250 MB. Above 10 MiB Microsoft advises createUploadSession, with fragments in multiples of 320 KiB and under 60 MiB each
2. Send the bearer token on the createUploadSession POST only. The PUT calls to uploadUrl can return 401 if an Authorization header is included
3. Set expirationDateTime and scope on createLink. Without a scope the tenant's default link type is created, which may be wider than intended
4. Follow the 302 from GET /content straight away. Pre-authenticated download URLs can expire within minutes and need no Authorization header
5. Wait for Retry-After on 429 and 503. Throttled requests still count against the limits, and continued overuse can get the app blocked