diff --git a/src/dns/gcdns.js b/src/dns/gcdns.js
index e5808eb2e..52e5e75a0 100644
--- a/src/dns/gcdns.js
+++ b/src/dns/gcdns.js
@@ -46,7 +46,6 @@ function getDnsCredentials(domainConfig) {
 async function getZoneByName(domainConfig, zoneName) {
     assert.strictEqual(typeof domainConfig, 'object');
     assert.strictEqual(typeof zoneName, 'string');
-    assert.strictEqual(typeof callback, 'function');
 
     const gcdns = new GCDNS(getDnsCredentials(domainConfig));
 
diff --git a/src/dns/manual.js b/src/dns/manual.js
index 27397868a..99a3427c9 100644
--- a/src/dns/manual.js
+++ b/src/dns/manual.js
@@ -69,7 +69,6 @@ async function wait(domainObject, subdomain, type, value, options) {
 
 async function verifyDomainConfig(domainObject) {
     assert.strictEqual(typeof domainObject, 'object');
-    assert.strictEqual(typeof callback, 'function');
 
     const zoneName = domainObject.zoneName;
 
diff --git a/src/dns/namecom.js b/src/dns/namecom.js
index 855df8e67..9f8f50353 100644
--- a/src/dns/namecom.js
+++ b/src/dns/namecom.js
@@ -79,7 +79,6 @@ async function updateRecord(domainConfig, zoneName, recordId, name, type, values
     assert.strictEqual(typeof name, 'string');
     assert.strictEqual(typeof type, 'string');
     assert(Array.isArray(values));
-    assert.strictEqual(typeof callback, 'function');
 
     debug(`update:${recordId} on ${name} in zone ${zoneName} of type ${type} with values ${JSON.stringify(values)}`);
 
diff --git a/src/dns/route53.js b/src/dns/route53.js
index 7d1c9e80e..054a13f6e 100644
--- a/src/dns/route53.js
+++ b/src/dns/route53.js
@@ -75,7 +75,6 @@ async function getZoneByName(domainConfig, zoneName) {
 async function getHostedZone(domainConfig, zoneName) {
     assert.strictEqual(typeof domainConfig, 'object');
     assert.strictEqual(typeof zoneName, 'string');
-    assert.strictEqual(typeof callback, 'function');
 
     const zone = await getZoneByName(domainConfig, zoneName);
 
diff --git a/src/dns/vultr.js b/src/dns/vultr.js
index 6411692e4..372f0ddbb 100644
--- a/src/dns/vultr.js
+++ b/src/dns/vultr.js
@@ -202,7 +202,6 @@ async function wait(domainObject, subdomain, type, value, options) {
 
 async function verifyDomainConfig(domainObject) {
     assert.strictEqual(typeof domainObject, 'object');
-    assert.strictEqual(typeof callback, 'function');
 
     const domainConfig = domainObject.config,
         zoneName = domainObject.zoneName;