diff --git a/lib/get-aws-sts-token.js b/lib/get-aws-sts-token.js
index 84bdd9a..4d9340e 100644
--- a/lib/get-aws-sts-token.js
+++ b/lib/get-aws-sts-token.js
@@ -5,17 +5,17 @@ const EXPIRY = 3600;
 
 async function getAwsAuthToken(
   logger, createHash, retrieveHash,
-  {accessKeyId, secretAccessKey, region, RoleArn}) {
+  {accessKeyId, secretAccessKey, region, roleArn}) {
   logger = logger || noopLogger;
   try {
-    const key = makeAwsKey(RoleArn || accessKeyId);
+    const key = makeAwsKey(roleArn || accessKeyId);
     const obj = await retrieveHash(key);
     if (obj) return {...obj, servedFromCache: true};
 
     let data;
-    if (RoleArn) {
+    if (roleArn) {
       const stsClient = new STSClient({ region });
-      const roleToAssume = { RoleArn, RoleSessionName: 'Jambonz_Speech', DurationSeconds: EXPIRY};
+      const roleToAssume = { RoleArn: roleArn, RoleSessionName: 'Jambonz_Speech', DurationSeconds: EXPIRY};
       const command = new AssumeRoleCommand(roleToAssume);
 
       data = await stsClient.send(command);
diff --git a/lib/get-tts-voices.js b/lib/get-tts-voices.js
index 98552ec..0376a5f 100644
--- a/lib/get-tts-voices.js
+++ b/lib/get-tts-voices.js
@@ -111,7 +111,7 @@ const getAwsVoices = async(_client, createHash, retrieveHash, logger, credential
           logger, createHash, retrieveHash,
           {
             region,
-            RoleArn: roleArn
+            roleArn
           }),
       });
     } else {
diff --git a/lib/synth-audio.js b/lib/synth-audio.js
index 1fb938d..516073c 100644
--- a/lib/synth-audio.js
+++ b/lib/synth-audio.js
@@ -285,7 +285,7 @@ const synthPolly = async(createHash, retrieveHash, logger,
           logger, createHash, retrieveHash,
           {
             region,
-            RoleArn: roleArn
+            roleArn
           }),
       });
     } else {