diff --git a/e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/EmailsFetcher.kt b/e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/EmailsFetcher.kt
index 01c0a9f..5c526b7 100644
--- a/e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/EmailsFetcher.kt
+++ b/e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/EmailsFetcher.kt
@@ -327,6 +327,7 @@ open class EmailsFetcher(
     }
 
     protected open fun mapAccountToJavaMailProperties(account: EmailAccount, options: FetchEmailsOptions) = Properties().apply {
+        // the documentation of all properties can be found here: https://javaee.github.io/javamail/docs/api/com/sun/mail/imap/package-summary.html
         put("mail.store.protocol", "imap")
 
         put("mail.imap.host", account.serverAddress)
@@ -336,6 +337,10 @@ open class EmailsFetcher(
         val timeout = (options.connectTimeoutSeconds * 1000).toString()
         put("mail.imap.connectiontimeout", timeout)
         put("mail.imap.timeout", timeout)
+
+        // speeds up fetching data tremendously
+        put("mail.imap.fetchsize", "819200") // Partial fetch size in bytes. Defaults to 16K.
+        put("mail.imap.partialfetch", "false") // Controls whether the IMAP partial-fetch capability should be used. Defaults to true.
     }
 
 }
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