diff --git a/src/serve_rendered.js b/src/serve_rendered.js
index 6968b43..da92fd6 100644
--- a/src/serve_rendered.js
+++ b/src/serve_rendered.js
@@ -33,7 +33,7 @@ import {
 const FLOAT_PATTERN = '[+-]?(?:\\d+|\\d+.?\\d+)';
 const PATH_PATTERN =
   /^((fill|stroke|width)\:[^\|]+\|)*(enc:.+|-?\d+(\.\d*)?,-?\d+(\.\d*)?(\|-?\d+(\.\d*)?,-?\d+(\.\d*)?)+)/;
-const httpTester = /^\/\//;
+const httpTester = /^(http(s)?:)?\/\//;
 
 const mercator = new SphericalMercator();
 const getScale = (scale) => (scale || '@1x').slice(1, 2) | 0;
diff --git a/src/serve_style.js b/src/serve_style.js
index 5f4e5ee..de981c7 100644
--- a/src/serve_style.js
+++ b/src/serve_style.js
@@ -9,7 +9,7 @@ import { validate } from '@maplibre/maplibre-gl-style-spec';
 
 import { getPublicUrl } from './utils.js';
 
-const httpTester = /^\/\//;
+const httpTester = /^(http(s)?:)?\/\//;
 
 const fixUrl = (req, url, publicUrl, opt_nokey) => {
   if (!url || typeof url !== 'string' || url.indexOf('local://') !== 0) {