diff --git a/author/author.go b/author/author.go
new file mode 100644
index 0000000..87a2239
--- /dev/null
+++ b/author/author.go
@@ -0,0 +1,116 @@
+package author
+
+import (
+	"github.com/writeas/writefreely/config"
+	"os"
+	"path/filepath"
+	"regexp"
+)
+
+// Regex pattern for valid usernames
+var validUsernameReg = regexp.MustCompile("^[a-zA-Z0-9][a-zA-Z0-9-]*$")
+
+// List of reserved usernames
+var reservedUsernames = map[string]bool{
+	"a":                true,
+	"about":            true,
+	"add":              true,
+	"admin":            true,
+	"administrator":    true,
+	"adminzone":        true,
+	"api":              true,
+	"article":          true,
+	"articles":         true,
+	"auth":             true,
+	"authenticate":     true,
+	"browse":           true,
+	"c":                true,
+	"categories":       true,
+	"category":         true,
+	"changes":          true,
+	"create":           true,
+	"css":              true,
+	"data":             true,
+	"dev":              true,
+	"developers":       true,
+	"draft":            true,
+	"drafts":           true,
+	"edit":             true,
+	"edits":            true,
+	"faq":              true,
+	"feed":             true,
+	"feedback":         true,
+	"guide":            true,
+	"guides":           true,
+	"help":             true,
+	"index":            true,
+	"js":               true,
+	"login":            true,
+	"logout":           true,
+	"me":               true,
+	"media":            true,
+	"meta":             true,
+	"metadata":         true,
+	"new":              true,
+	"news":             true,
+	"post":             true,
+	"posts":            true,
+	"privacy":          true,
+	"publication":      true,
+	"publications":     true,
+	"publish":          true,
+	"random":           true,
+	"read":             true,
+	"reader":           true,
+	"register":         true,
+	"remove":           true,
+	"signin":           true,
+	"signout":          true,
+	"signup":           true,
+	"start":            true,
+	"status":           true,
+	"summary":          true,
+	"support":          true,
+	"tag":              true,
+	"tags":             true,
+	"team":             true,
+	"template":         true,
+	"templates":        true,
+	"terms":            true,
+	"terms-of-service": true,
+	"termsofservice":   true,
+	"theme":            true,
+	"themes":           true,
+	"tips":             true,
+	"tos":              true,
+	"update":           true,
+	"updates":          true,
+	"user":             true,
+	"users":            true,
+	"yourname":         true,
+}
+
+// IsValidUsername returns true if a given username is neither reserved nor
+// of the correct format.
+func IsValidUsername(cfg *config.Config, username string) bool {
+	// Username has to be above a character limit
+	if len(username) < cfg.App.MinUsernameLen {
+		return false
+	}
+	// Username is invalid if page with the same name exists. So traverse
+	// available pages, adding them to reservedUsernames map that'll be checked
+	// later.
+	// TODO: use pagesDir const
+	filepath.Walk("pages/", func(path string, i os.FileInfo, err error) error {
+		reservedUsernames[i.Name()] = true
+		return nil
+	})
+
+	// Username is invalid if it is reserved!
+	if _, reserved := reservedUsernames[username]; reserved {
+		return false
+	}
+
+	// TODO: use correct regexp function here
+	return len(validUsernameReg.FindStringSubmatch(username)) > 0
+}