diff --git a/src/FileUploader.ts b/src/FileUploader.ts
index 8bd62be..c7be45a 100644
--- a/src/FileUploader.ts
+++ b/src/FileUploader.ts
@@ -1,4 +1,4 @@
-import { isLogInRequired, needsRetry } from './utils'
+import { isLogInRequired, needsRetry, isUrl } from './utils'
 import { CsrfToken } from './types/CsrfToken'
 import { UploadFile } from './types/UploadFile'
 
@@ -11,7 +11,10 @@ export class FileUploader {
     private jobsPath: string,
     private setCsrfTokenWeb: any,
     private csrfToken: CsrfToken | null = null
-  ) {}
+  ) {
+    if (serverUrl) isUrl(serverUrl)
+  }
+
   private retryCount = 0
 
   public uploadFile(sasJob: string, files: UploadFile[], params: any) {
diff --git a/src/SAS9ApiClient.ts b/src/SAS9ApiClient.ts
index 010d63a..40ffb09 100644
--- a/src/SAS9ApiClient.ts
+++ b/src/SAS9ApiClient.ts
@@ -1,9 +1,13 @@
+import { isUrl } from './utils'
+
 /**
  * A client for interfacing with the SAS9 REST API
  *
  */
 export class SAS9ApiClient {
-  constructor(private serverUrl: string) {}
+  constructor(private serverUrl: string) {
+    if (serverUrl) isUrl(serverUrl)
+  }
 
   /**
    * returns on object containing the server URL
diff --git a/src/SASViyaApiClient.ts b/src/SASViyaApiClient.ts
index b560076..31dd8a4 100644
--- a/src/SASViyaApiClient.ts
+++ b/src/SASViyaApiClient.ts
@@ -2,7 +2,8 @@ import {
   isAuthorizeFormRequired,
   parseAndSubmitAuthorizeForm,
   convertToCSV,
-  makeRequest
+  makeRequest,
+  isUrl
 } from './utils'
 import * as NodeFormData from 'form-data'
 import * as path from 'path'
@@ -26,7 +27,10 @@ export class SASViyaApiClient {
     if (!rootFolderName) {
       throw new Error('Root folder must be provided.')
     }
+
+    if (serverUrl) isUrl(serverUrl)
   }
+
   private csrfToken: CsrfToken | null = null
   private rootFolder: Folder | null = null
   private sessionManager = new SessionManager(
diff --git a/src/SessionManager.ts b/src/SessionManager.ts
index 5a782c2..a0c6fb9 100644
--- a/src/SessionManager.ts
+++ b/src/SessionManager.ts
@@ -1,5 +1,5 @@
 import { Session, Context, CsrfToken } from './types'
-import { asyncForEach, makeRequest } from './utils'
+import { asyncForEach, makeRequest, isUrl } from './utils'
 
 const MAX_SESSION_COUNT = 1
 
@@ -8,7 +8,10 @@ export class SessionManager {
     private serverUrl: string,
     private contextName: string,
     private setCsrfToken: (csrfToken: CsrfToken) => void
-  ) {}
+  ) {
+    if (serverUrl) isUrl(serverUrl)
+  }
+
   private sessions: Session[] = []
   private currentContext: Context | null = null
   private csrfToken: CsrfToken | null = null
diff --git a/src/utils/index.ts b/src/utils/index.ts
index 6a15042..0eb205b 100644
--- a/src/utils/index.ts
+++ b/src/utils/index.ts
@@ -13,3 +13,4 @@ export * from './parseSasViyaLog'
 export * from './serialize'
 export * from './splitChunks'
 export * from './parseWeboutResponse'
+export * from './isUrl'
diff --git a/src/utils/isUrl.ts b/src/utils/isUrl.ts
new file mode 100644
index 0000000..1e64fa7
--- /dev/null
+++ b/src/utils/isUrl.ts
@@ -0,0 +1,12 @@
+export const isUrl = (url: string): boolean => {
+  const pattern = new RegExp(
+    '^(http://|https://)[a-z0-9]+([-.]{1}[a-z0-9]+)*.[a-z]{2,5}(:[0-9]{1,5})?(/.*)?$',
+    'gi'
+  )
+
+  if (pattern.test(url)) return true
+  else
+    throw new Error(
+      `'${url}' is not a valid url. An example of a valid url is 'http://valid-url.com'.`
+    )
+}