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A ‘premium’ version of this plugin is now available. See our downloads page for details.

We’ve had a few goodies for WordPress get added to our Downloads page recently. From an addon to the popular Contact Form 7 plugin, to Campaign Press for resellers, there’s been plenty to keep fans of the popular CMS amused.

A sample completed subscribe form

Despite the seeming abundance of addons for existing form plugins, there has been one thing missing – a standalone widget for adding a Campaign Monitor subscribe form to the sidebar of a WordPress-powered site. That was until the Campaign Monitor Ajax Subscription Widget for WordPress neatly filled this gap, providing a convenient way for designers to add a form to their site and for visitors to opt-in for email newsletters and announcements, without having to sit through an unnecessary page load.

This widget takes the pain out of setting up a subscribe form – all you have to do is add a form title, your Campaign Monitor API key and the List ID for an existing subscriber list in your account. The result is a simple form that collects names, email addresses and provides a simple confirmation message on signup.

In the next update, a shortcode will be provided so a form can be added anywhere on a WordPress page or post.

Many thanks to developer Lee Willis for sharing this awesome plugin for free – he’s also responsible for the VirtueMart plugin for Joomla! that we’ve also featured. You can install the Campaign Monitor Ajax Subscription Widget for WordPress from within the ‘Plugins’ section of your WordPress dashboard or via WordPress.org. To view more details and screenshots, visit Lee’s website.

  • Scott Offord

    Why is it so hard to find these two API keys in the CM account???

  • David Greiner

    Scott, apologies for any problems you had tracking them down. You can find good instructions on this here. We have plans to centralise all of this in your account soon to make this an easier process.

  • Myself

    FYI, you have some missing screenshots/images here: https://www.campaignmonitor.com/api/getting-started/

  • Ros Hodgekiss

    Thanks for letting us know, we’ll get them fixed up shortly. :D

  • Jeffrey Brown

    I’ve installed this… double and triple checked everything and tried it every which way I can… And, I’m still getting this message:

    “Sorry, we weren’t able to sign you up. Please check your details, and try again.”

    Any clues… have left a reply on the developers site but that hasn’t even been moderated yet. Love CM, been there for years… hope this gets fixed.


  • Ros Hodgekiss

    @Jeff – Thanks Jeff, unfortunately we can’t offer any support for this plugin on our end, but we’ll follow up with the developer

  • Lee Willis

    I exchanged a few emails with Jeff last night, we’re still working through what the problem might be – I’ll update here if there’s any updates needed to the plugin.

  • Lee Willis

    Looks like just confusion over which API key is which…..

  • Scott Offord

    excellent. thanks for the update.

  • Óli Jón

    I have the same problem as Jeff using CM Ajax Forms. There are three API keys to choose from, as far as I can see:

    API Account ID
    API Client ID
    API List ID

    Which one goes into:

    Account API Key
    List API Key

    I have tried every combination without success.

    – Oli

  • Lee Willis

    Hi Óli Jón – think we’ve got your issue sorted – it was a PHP compatibility issue – ideally the plugin needs PHP 5.2 or higher.

  • Óli Jón


    Thank you very much for your truly excellent service! The way you stand behind your excellent (and free) product is admirable.

    The very best to you, kind sir!

    – Óli

  • sue

    will this form work for a SquareSpace site?

  • Ros Hodgekiss

    Hi sue, you would be better off using our other AJAX subscribe form. Check out this page on adding JavaScript to Squarespace sites, as you may have to do a bit of legwork to get this happening.

  • Jonathan Slatter

    Hi – I can’t get this to work using 1&1 server. I have the CM Account API and List API in the widget, but I always just get this message when i try and subscribe an email address: “Sorry, we weren’t able to sign you up. Please check your details, and try again”

    On my 1&1 Control panel it says MySQL DB is version 5.0 – do you think that is the problem? Does it have to be 5.2? Is there any way around it?

    Looks like such a neat widget, I would love to get this working.

    BTW – I have your shipping plug for WP E-commerce – and that is excellent (now that I have taken the UK into their own unique continent!)
    Thanks for your excellent work Lee.


  • Lee Willis

    Hi Jonathan – think we’ve already got your issue sorted? It was a PHP compatibility issue same as Óli Jón.

This blog provides general information and discussion about email marketing and related subjects. The content provided in this blog ("Content”), should not be construed as and is not intended to constitute financial, legal or tax advice. You should seek the advice of professionals prior to acting upon any information contained in the Content. All Content is provided strictly “as is” and we make no warranty or representation of any kind regarding the Content.
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