diff --git a/src/inc/companies.php b/src/inc/companies.php
new file mode 100644
index 0000000..702151f
--- /dev/null
+++ b/src/inc/companies.php
@@ -0,0 +1,58 @@
+<?php
+class companies {
+  public static function add($company, $cif) {
+    global $con;
+
+    $scompany = db::sanitize($company);
+    $scif = db::sanitize($cif);
+    return mysqli_query($con, "INSERT INTO companies (name, cif) VALUES ('$scompany', '$scif')");
+  }
+
+  public static function edit($id, $name, $cif) {
+    global $con;
+
+    $sid = (int)$id;
+    $sname = db::sanitize($name);
+    $scif = db::sanitize($cif);
+
+    return mysqli_query($con, "UPDATE companies SET name = '$sname', cif = '$scif' WHERE id = $sid LIMIT 1");
+  }
+
+  public static function get($id) {
+    global $con;
+
+    $sid = (int)$id;
+
+    $query = mysqli_query($con, "SELECT * FROM companies WHERE id = $sid");
+
+    if (!mysqli_num_rows($query)) return false;
+
+    return mysqli_fetch_assoc($query);
+  }
+
+  public static function getAll($simplified = true, $mixed = false) {
+    global $con;
+
+    $query = mysqli_query($con, "SELECT * FROM companies ORDER BY id ASC");
+
+    $categories = [];
+
+    while ($row = mysqli_fetch_assoc($query)) {
+      if ($simplified) $categories[$row["id"]] = $row["name"];
+      elseif ($mixed) $categories[$row["id"]] = $row;
+      else $categories[] = $row;
+    }
+
+    return $categories;
+  }
+
+  public static function exists($id) {
+    global $con;
+
+    if ($id == -1) return true;
+
+    $query = mysqli_query($con, "SELECT id FROM companies WHERE id = ".(int)$id);
+
+    return (mysqli_num_rows($query) > 0);
+  }
+}