When running Duplicity with Backblaze's B2 as outlined in some articles:

duplicity ~ b2://[keyID]:[application key]@[B2 bucket name]

Real values hidden, but provided though the Backblaze B2 UI.

I encounter the following error:

InvalidBackendURL: Syntax error (port) in: b2://[keyID]:[application key]@[B2 bucket name] AFalse BNone [keyID]:[application key partial]\

Where the application key is partially chopped off at the slash. I have attempted many alternatives to escape the slash such as double quotes, single quotes, and backslash escaping, but nothing improves the situation.

2 Answers 2


as the target is given in url format


actually the proper solution would be to url-encode the userinfo, the part between schema:// and the @ . slash '/' for obvious reason is an illegal character there so it needs to be escaped which should be done via percent-encoding (url-encoding) https://en.wikipedia.org/wiki/Percent-encoding . e.g.

duplicity ~ b2://keyID:application/key@[B2 bucket name]

would need to become

duplicity ~ b2://keyID:application%2Fkey@[B2 bucket name]

because '/' is '%2F' percent encoded.

have fun.. ede/duply.net

  • As user ede-duply.net replied, replace "/" in the applicationKey with "%2" Commented Sep 24, 2022 at 13:54
  • @overthehills wouldn't that be '%2F' ? just updated my answer to be more explicit. Commented Sep 26, 2022 at 23:37

The only resolution I have found is to create a new application key in the Backblaze B2 UI that does not include a slash. The creation of a new application key may need to be repeated several times to get one without a slash.

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