diff --git a/API.md b/API.md
index 88b1b70..e6cedc3 100644
--- a/API.md
+++ b/API.md
@@ -75,10 +75,10 @@ var pass = new Pass(options);
| options | Object | The options to create the pass | false | -
| options.model | String/Path | The model path to be used to generate a new model. | false | -
| options.certificates | Object | The certificate object containing the paths to certs files. | false | -
-| options.certificates.wwdr | String/Path | The path to Apple WWDR certificate. | false | -
-| options.certificates.signerCert | String/Path | The path to Developer certificate file. | false | -
-| options.certificates.signerKey | Object | The object containing developer certificate's key and passphrase. | false | -
-| options.certificates.signerKey.keyFile | String/Path | The path to developer certificate key. | false | -
+| options.certificates.wwdr | String/Path | The path to Apple WWDR certificate or its content. | false | -
+| options.certificates.signerCert | String/Path | The path to Developer certificate file or its content. | false | -
+| options.certificates.signerKey | Object/String | The object containing developer certificate's key and passphrase. If string, it can be the path to the key file or its content. If object, must have `keyFile` key and might need `passphrase`. | false | -
+| options.certificates.signerKey.keyFile | String/Path | The path to developer certificate key or its content. | false | -
| options.certificates.signerKey.passphrase | String \| Number | The passphrase to use to unlock the key. | false | -
| options.overrides | Object | Dictionary containing all the keys you can override in the pass.json file and does not have a method to get overridden. | true | { }
| options.shouldOverwrite | Boolean | Setting this property to false, will make properties in `overrides` and fields to be pushed along with the ones added through methods to the existing ones in pass.json. | true | true
diff --git a/README.md b/README.md
index 2958117..0e848fb 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,8 @@
Simple Node.js interface to generate customized Apple Wallet Passes for iOS.
+
+