diff --git a/lib/synth-audio.js b/lib/synth-audio.js
index 7d25038..5db3ac4 100644
--- a/lib/synth-audio.js
+++ b/lib/synth-audio.js
@@ -1295,7 +1295,7 @@ const synthCartesia = async(logger, {
 const synthResemble = async(logger, {
   credentials, options, stats, voice, text, renderForCaching, disableTtsStreaming
 }) => {
-  const {api_key, resemble_tts_uri} = credentials;
+  const {api_key, resemble_tts_uri, resemble_tts_use_tls} = credentials;
   const {project_uuid, use_hd} = options || {};
 
   /* default to using the streaming interface, unless disabled by env var OR we want just a cache file */
@@ -1308,6 +1308,7 @@ const synthResemble = async(logger, {
     if (project_uuid) params += `,project_uuid=${project_uuid}`;
     if (use_hd) params += `,use_hd=${use_hd}`;
     if (resemble_tts_uri) params += `,endpoint=${resemble_tts_uri}`;
+    if (resemble_tts_use_tls) params += `,use_tls=${resemble_tts_use_tls}`;
 
     params += '}';