diff --git a/genmanifest/genmanifest.go b/genmanifest/genmanifest.go
new file mode 100644
index 0000000..958928f
--- /dev/null
+++ b/genmanifest/genmanifest.go
@@ -0,0 +1,121 @@
+// Utility to generate web extension manifest files from GJSON (Generic JSON)
+// templates, given some dependencies.
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"regexp"
+	"strings"
+)
+
+var beginningOfIfStatement = regexp.MustCompile(`^\s*#if defined\(([^\(\)]*)\)\s*$`)
+var endOfIfStatement = regexp.MustCompile(`^\s*#endif\s*$`)
+
+var (
+  quietMode = flag.Bool("quiet", false, "Quiet mode")
+	templateFile = flag.String("template", "", "Template file")
+	destFile = flag.String("dest", "", "Destination file")
+)
+
+// findWithCaseFolding returns whether there is some element of slice which is
+// equal to val under Unicode case-folding.
+func findWithCaseFolding(slice []string, val string) bool {
+	for _, item := range slice {
+		if strings.EqualFold(item, val) {
+			return true
+		}
+	}
+	return false
+}
+
+// Given a Generic JSON (GJSON) template and the dependencies met,
+// WriteManifest will write at dest the manifest file generated from the
+// template according to the dependencies.
+func WriteManifest(template io.Reader, dest io.Writer, dependencies []string) error {
+	level := 0
+	activeLevel := 0
+	scanner := bufio.NewScanner(template)
+	for scanner.Scan() {
+		line := scanner.Text()
+		considerLine := false
+		if m := beginningOfIfStatement.FindStringSubmatch(line); m != nil {
+			if level == activeLevel {
+				statementDeps := m[1]
+				deps := strings.Split(statementDeps, "||")
+				for _, dep := range deps {
+					dep = strings.TrimSpace(dep)
+					if findWithCaseFolding(dependencies, dep) {
+						activeLevel++
+						break
+					}
+				}
+			}
+			level++
+		} else if m := endOfIfStatement.MatchString(line); m {
+			if activeLevel == level {
+				activeLevel--
+			}
+			level--
+		} else {
+			considerLine = level == activeLevel
+		}
+
+		if considerLine {
+			_, err := io.WriteString(dest, line+"\n")
+			if err != nil {
+				return fmt.Errorf("Can't write manifest: %v", err)
+			}
+		}
+	}
+
+	return nil
+}
+
+// WriteManifestFileNames is the same as WriteManifest, but instead of receiving
+// read and write handlers for each file, this function receives the file names
+// as strings and reads/writes from/to those files.
+func WriteManifestFileNames(templateFile string, destFile string, dependencies []string) error {
+	template, err := os.Open(templateFile)
+	if err != nil {
+		return fmt.Errorf("Couldn't open file %v: %v", templateFile, err)
+	}
+	defer template.Close()
+
+	dest, err := os.Create(destFile)
+	if err != nil {
+		return fmt.Errorf("Couldn't create file %v: %v", destFile, err)
+	}
+	defer dest.Close()
+
+	return WriteManifest(template, dest, dependencies)
+}
+
+func main() {
+	log.SetPrefix("generatemanifest: ")
+  log.SetFlags(0)
+
+  flag.Parse()
+  dependencies := flag.Args()
+
+  if len(dependencies) == 0 {
+    log.Fatalf("Pass the dependencies as arguments (for instance, run `go run generateManifest.go CHROMIUM`).")
+  }
+	if (*templateFile == "") {
+		log.Fatalf("Pass the template file name via the -template flag.")
+	}
+	if (*destFile == "") {
+		log.Fatalf("Pass the destination file name via the -dest flag.")
+	}
+
+	err := WriteManifestFileNames(*templateFile, *destFile, dependencies)
+  if err != nil {
+    log.Fatalf("%v", err)
+  } else if !*quietMode {
+    log.Println("Manifest has been generated successfully")
+  }
+}