Error 404; API URL changed

Occasional Participant

Error 404; API URL changed


We just started receiving 404 server response when using the API during the registration process to our Web Site.

The call to API in made to supply a new registrant’s info to Constant Contact to enable sending recurring emails .

The URL triggering the 404 response is

+ dynamic part consisting of several field-value pairs to pass needed email content identification and new Contact (registrant) info to API:


This is the sample of dynamic part:

ic=Coupon%20Sentinel%20-%20Press%20Edition& SomeCompany &Home_Phone=&Address_Line_1=&Address_Line_2=&City=&State=&Country=&Postal_Code=&Email_Type=H"


This was working for several years, and suddenly stopped working.

The loginName / loginPassword remain valid the for the account.

We contacted the general support, and they suggested all new base URL:


We appended the existing dynamic part to it, and attempted to register.

The registration went through (there was no 404 response from API anymore); however, the new Contact info did not get into Constant Contact at all.


In other words, people could register, but they will not get emails they opted for.

The registration process is completely compromised, and this situation needs to be resolved ASAP.


If you need examples of actual requests to Constant Contact API made during registration attempts, please contact us directly:

Thanks in advance for your support.


We did find that some customers who are using certain older versions of the SiteVisitor API are now receiving a 404 page not found when trying to use them.  We have over the years updated the URL in our documentation and in our systems, but up until this past week we have always maintained a backwards compatibility with redirects.  We did some security work this weekend that caused these redirects to no longer work.


You will want to use this URL to get this to work going forward.  Again though, this is a depricated API and this API will be fully retired at a future date.  We recommend anyone using this API start the process of updating sooner to make the change over easier.

David J

Occasional Participant

We did not have any issues with; however, did not always work.

Our users subscribe to the one type of email based on their preferences.

When they change their preferences our site requests API_UnsubscribeSiteVisitor.jsp to remove the old subscription,

then API_AddSiteVisitor.jsp to add a new one.

It works well at times; however, sometimes we still see 2 subscriptions in Constant Contact.

If we request a problematic URL .. API_UnsubscribeSiteVisitor.jsp..  in the IE browser, we get the IE download error message, but the subscription is gone from Constant Contact.

Not sure what the problem may be.


We'll take a look at this problem on our end.  A better solution for you though would be to implement out REST APIs and phase out the Site Visitor API.  The REST API allows you to check to see if someone already exists and if they do, you can pull out all their existing information and allow them to update it.  

Dave Berard
Senior Product Manager, Constant Contact
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