MB Builder 5.0.0 RC1: Performance Optimized, Live Preview for Columns and More

After months of building, testing, and gathering valuable feedback from users through the Alpha and Beta releases, MB Builder 5.0.0 RC1 is now officially available, packed with all the powerful features and ready for use.

This release marks a major milestone, not only with a refreshed interface but also with significant improvements in performance, usability, and flexibility. Specifically, it brings:

• Extreme performance boost with AJAX saving for smooth, reload-free field editing.
• The addition of the floating structure panel lets you configure fields while keeping full visibility and control over the entire field group layout.
• Live preview for MB Columns allows you to set the custom column in the Settings panel or resize right on the live preview.
• Full merged with recent updates from the main version which now supports for Local JSON, WPML & Polylang integrations, making it ready for use.

This version is now available for download and testing.

We’re beyond excited to finally share these changes with you. Let’s dive in!

Optimized Performance

We’ve always aimed to make each version release faster than the last, and RC1 is no exception. This version brings a massive performance boost, especially noticeable when working with field groups that contain hundreds. We tested on a field group that has about 300 fields and nested groups up to 4 or 5 levels.

In the RC1 version, we rewrote how data is saved. Leverage the power of AJAX-based saving and improved loading logic. As a result, everything takes effect instantly the moment you click. No more losing fields due to premature saving, everything is now safely handled behind the scenes.

You can now confidently work on large, complex field structures, switching between tabs, editing fields, or saving drafts without delays or accidental data loss. The experience is smoother, faster, and more reliable than ever.

Floating Structure Panel

During the two earlier stages, we received a flood of user suggestions about the layout, where the panels should live, such as a dual sidebar, an option to choose whether the panel will be on the left or right, etc. We tested every layout you proposed. To ensure your experience and page speed, we decided to keep the main structure panel on the left and add an option to make it floating as below:

When you click a field in the floating structure panel, that field is instantly highlighted in the live preview, along with its settings. This brings out the biggest advantage of this layout: you can edit the field’s settings while keeping a clear overview of the entire field group structure.

You can move the floating panel anywhere you want. That new position will be remembered. On this panel, you can close, open, as well as drag and drop to rearrange the fields and subfields, or use the quick action.

There is a small but useful change: You can now collapse or expand all groups in both normal and floating structure panels, making it much easier to manage complex field groups.

To us, this interface is a perfect balance between WordPress familiarity and page builder style. We continue to follow the principles: stay true to the native feel while optimizing your workflow and overall performance. So, as you can see, the floating structure panel takes inspiration from the structure tools used in today’s most popular page builders.

Two-Way Interaction Between MB Columns and Live Preview

As you may already know, live preview for settings is one of the most significant improvements in MB Builder 5.0.0. And with the RC1 version, we’ve taken it even further by extending to MB Columns. This is one of the most exciting refinements in this release.

Now, when you adjust the number of grids to put your custom fields into in the Appearance tab, you can instantly see how the layout changes, no guesswork, no reloading. It works well with both fields and subfields in a group. Then, you can easily choose the most suitable layout without having to switch screens or update multiple times.

Another way is you can resize the field directly in the live preview, and the value of the custom column will be updated to the setting of that field automatically.

There’s a small visual change, but don’t worry, it doesn’t affect your fields at all. By default, the label is left-aligned. However, if there is at least one field with a custom column, labels will automatically shift above the input. This adjustment helps preserve the exact width you’ve set for each field, especially in tighter layouts where space is limited.

Together, these additions give you full control over how and where your data is stored and reused, whether you're developing solo or collaborating on a larger project.

Others

We also enhance UX with a toolbar. You just need to hover over the field, then its toolbar will display instead of clicking as previously. Saving one click saves your time and effort.

Besides, all the bugs you reported on the Beta version are fixed.

Last Words

We’ve packed a lot into this release from performance enhancements and better layout controls, to a more intuitive editing experience. These changes are built around real user feedback and real-world workflows, and we believe they’ll make your daily work with custom fields easier and more enjoyable than ever.

Please give the MB Builder 5.0.0 RC1 for a spin, explore all the improvements, and let us know what you think. Your feedback is what drives Meta Box forward, and we can’t wait to hear from you.