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Frequently Asked Questions

If you don't find the answers to you questions here, check our Developer Documentation.

The Basics

  • What is CloudSponge?

    CloudSponge is a software-as-a-service product that imports all the major address books. Most websites use our product so that their users don’t have to type email addresses into their referral forms when they want to send an invitation, greeting card or coupon to someone they know.

  • Which contact sources does CloudSponge support?

    Please visit our contact sources directory for an up to date list of our supported address books along with real time availability monitoring.

    We continue to add support for more contact sources. If you would like to be notified when we have added support for a particular contact source, please send us feedback.

  • What browsers does CloudSponge support?

    CloudSponge supports the major browsers on Windows, Mac and mobile systems:</p>

    • Chrome
    • FireFox
    • Internet Explorer 7+
    • Safari
    • Mobile Safari
  • Do I have to be a programmer to use CloudSponge?

    No. A little programming knowledge is helpful, but we give you a simple piece of code that you can paste into the page on your website with your referral form.

    If you are a programmer, you will find dozens of customization options in our Developer Documentation including the ability to use our API so that you can have complete control over every pixel of the user experience.

Using CloudSponge

  • Does CloudSponge also send emails to my users for me?

    No. We’re only handling the address book importing part of the solution for you. You’ll have to send the invitations or coupons to your users’ friends yourself. For transactional email delivery we highly recommend SendGrid rather than using your own mail server.

  • Can I customize the CloudSponge widget?

    Absolutely! There are tons of ways you can customize the widget, we’ve written a whole section about widget customizations in our Developer Documentation.

  • Do I have to use your “Choose Your Contacts” page?

    No. You can let our widget guide the user through importing their contacts, then pass the contacts to your application to render them. The beforeDisplayContacts callback lets you get the full list of contacts in JavaScript and suppress the display of the contact chooser. Find a minimal example here.

  • When I try to use the widget, I see a popup saying something about ‘quirks mode’. How do I resolve this?

    The widget must be included on a page with a valid doctype tag. Insert <!DOCTYPE html> in the first line of your page to enable the widget.

  • Is there a known issue with this importing from OS X Contacts and/or Outlook?

    There can be an issue when the browser’s Java Plugin is disabled. This most commonly happens with FireFox but is known to happen with other browsers. Enabling your browser’s Java Plugin will resolve this.

  • Why doesn’t every contact in my address book appear in the widget?

    You may not see every contact in the widget because CloudSponge only displays contacts that pass through some simple email validation. This ensures that your application only gets a list of contacts with reasonable looking email addresses.

    One common address that is filtered is the Exchange address. These addresses generally follow this format:

    /o=ORGANIZATION_NAME/ou=organizational group/cd=RECIPIENTS/cn=username</code>

    If you would like all the emails to appear in the widget, you can set an option to override the filtering of these emails. Specifying:

    performEmailValidation: false

    in the csPageOptions will display every contact with an email address, valid or not.

  • How do I brand the AOL import user experience?

    Branding the AOL experience is only possible if you have an existing developer relationship with AOL.

  • How do I fix the “invalid client” error after I change the branding for Gmail?

    After applying the changes to see your domain in the Google Authentication window, you may still get an invalid client error from Google.

    That error is displayed when under “APIs & auth” -> “Consent screen” you have empty field. Make sure the field “Product Name” is correctly filled in and that you have also selected an e-mail address. You can find “Consent screen” by going to Then, click on your project’s name and go to “APIs & auth” -> “Consent screen”.

  • Are you sure that the CloudSponge servers can handle my traffic?

    The CloudSponge servers are hosted by Amazon Web Services with redundancy at every level of the stack and load balancing on our most critical parts.

    Operating on thousands of websites for several years has given us all the data we need to know exactly how much activity each of our server instances can handle. Our monitoring thresholds are set at “better-safe-than-sorry” levels to make sure we are notified well in advance of any bottlenecks forming.

    The ability to launch more server instances instantly coupled with our generous monitoring thresholds gives us full confidence that we can handle any amount of traffic that your website can send our way.

  • Does Yahoo return the name of the account owner through your API?

    Yes it does. It requires that the user grant access to read the user’s Yahoo Mail during the OAuth flow.

    In general, we return the contacts_owner whenever possible, but in some cases this is not possible, e.g. from a CSV upload or if your Yahoo credentials don’t include the Yahoo Mail scope.

  • I registered How can I make my domain key work on

    When you register a domain, the domain key will work on more specific subdomains like However the inverse is not true. If you register, the domain key will not work on

    The solution to this is to transfer your domain to be You can do that from the ‘Cancel’ tab of the domain details page.

    If you are registering a new domain, we always recommend registering the apex domain (e.g. so it can also be used on subdomains. The exception to this is when your site is hosted on another service that uses a subdomain to redirect to your.

    Exceptions: My site is hosted on Using the full subdomain is appropriate here. My site is always available on If your site has a url rewrite from -> or these domains point to different sites, then of course it makes sense to register the subdomain.

Security & Privacy

  • Does CloudSponge keep my users’ address books?

    No. Your user’s address book will stay in memory on our servers for a few minutes so that your website has a chance to download it, but then it’s wiped from memory and never written to disk.

  • How does CloudSponge handle my users’ login credentials for the address book sources?

    In most cases, we never see the credentials. Google, Yahoo and Microsoft all have delegated authentication frameworks that ensure that their users never have to give their credentials away to third parties like us. Desktop address books like Outlook and OS X Contacts use an applet that your users have to allow to run before we can access their data. For the other address book sources, we never save their credentials to disk and we wipe it from our server’s memory after a few minutes.