This plugin allows you to easily embed Web forms built with Formstack's online form builder into your sidebar, pages, and posts.
As of April 2026, Formstack Online Forms is a WordPress forms plugin with 1.0K+ active installations and a 2.5/5 rating from 8 reviews. It has been downloaded 82K+ times in total. Requires WordPress 2.8+ and PHP false+. Available on WordPress.org since 2010. Last updated 6 years ago — may have compatibility concerns. Download volume is stable this week. Top alternative: WPForms – Easy Form Builder for….
Formstack’s WordPress form plugin makes it quick and easy to embed contact forms, lead generation forms, payment forms, and more on your WordPress blogs and websites. Build customized online forms in seconds with our drag-and-drop interface, and integrate with 40+ third-party apps, including Salesforce, MailChimp, and PayPal.
This plugin features two components:
The Formstack widget allows you to embed Formstack web forms into your sidebar. The widget automatically optimizes the web form’s CSS to make your online forms fit and look great on your WordPress pages.
The Formstack Plugin adds a button to the TinyMCE editor that allows you to easily select the Formstack web form you wish to embed. Once a form is selected, a shortcode will be inserted into the…
For a system that asks a lot of money for their service, you would think they would keep their features up to date. Nope. Can’t use this plugin, it just errors out. Can’t even use their embed javascript because you get a 403 server error.
It seem like you guys are trying to do too many things, but nothing works properly.
Signed up with Formstack, your Drupal extension doesn’t work, this WordPress extension doesn’t work either. It sends people to Formstack for confirmation instead of staying on the same page.
This plugin hasn’t been updated for 2 years.
.. wtf!
The only thing I’m stuck with are iFrames. These suck, but at least work.
Get a grip guys. You charge a lot of money for your service.
The previous plugin worked fine. This won’t authenticate and won’t allow me access to my forms.
When saving new API and client ID it gives me this:
Warning: Invalid argument supplied for foreach() in /home2/ogom/public_html/wp-content/plugins/formstack/plugin.php on line 288
Warning: Invalid argument supplied for foreach() in /home2/ogom/public_html/wp-content/plugins/formstack/plugin.php on line 288
Warning: Cannot modify header information – headers already sent by (output started at /home2/ogom/public_html/wp-content/plugins/formstack/plugin.php:288) in /home2/ogom/public_html/wp-includes/pluggable.php on line 1210
Form cache can be refreshed immediately to pull in new forms rather than wait an unknown period for the new form to appear in your list. With 300+ forms the old plugin was quite slow, this one loads the forms from a cache, thus loads relatively immediately compared to the APIv1.
Overall huge improvement. I would have given it 4/5 stars because the forms aren’t ordered, but Michael who made the plugin is amazing and provided a workaround via the support thread. Quite easy fix with roughly 4 lines of code (not sure why they haven’t pushed the changes as 2.0.2).
Formstack is a great product overall, integrating with major players. If I had to give a cost to formstack in general (not the plugin) higher than average cost would be the biggest drawback for most small businesses.
Ignore the 1 star reviews, this plugin works just fine if you can handle 5 minutes of setup.
From Formstack’s own website… “compatible with up to WordPress 4.0”
It wants you to use Formstack’s API v1 which is now deprecated and discouraged BY FORMSTACK!
Do not install this plugin!
| WordPress | 2.8+ requiredTested up to 5.1.22 |
| PHP | false+ required |
Plugin data sourced from WordPress.org. Analysis and metrics by PluginSift.