# Flexcard build and maintenance best practices

*Omnistudio Developer Study Guide · Flexcards · Last updated October 27, 2026 · https://www.certifyforce.com/study-guide/omnistudio-developer/flexcards/flexcard-build-and-maintenance-best-practices*

The Flexcard practices a developer applies while building and maintaining cards: moving cards to the standard designer through a new version, the 15-20 minute update delay and the Template API setting, parent data nodes that bypass the child's source, safe custom CSS, performance settings and Design Assistant recommended limits.

- Certification: Salesforce Omnistudio Developer
- Exam section: Flexcards
- Study guide: https://www.certifyforce.com/study-guide/omnistudio-developer

**Official exam objective:**

> Describe best practices for Flexcards.

## What the exam expects

- Move managed-package-designer cards to the standard designer without losing the ability to edit them in the old designer.
- Explain why an updated card still shows the old version and what to do about it.
- Make sure a child card that receives a parent data node gets every field it displays.
- Keep custom CSS maintainable, and apply the performance settings and recommended limits the designer checks.

Key terms: **standard designer** (the Flexcard designer in Omnistudio Standard Runtime), **Template API** (a setting Salesforce Support enables so updates appear faster), **data node** (the parent data passed to a child card, such as `{records[0]}`), **Design Assistant** (real-time health feedback in the designer), **recommended limit** (a threshold that triggers an informational or warning message).

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Switching designers | Create a new version in the managed package designer first | [Standard Designer Best Practices](https://help.salesforce.com/s/articleView?id=xcloud.os_best_practices_for_using_the_omnistudio_standard_designer.htm&language=en_US&type=5) |
| One-way open | Opened in the standard designer, a component can't be edited in the managed package designer | [Standard Designer Best Practices](https://help.salesforce.com/s/articleView?id=xcloud.os_best_practices_for_using_the_omnistudio_standard_designer.htm&language=en_US&type=5) |
| Update delay | Allow 15–20 minutes, even after clearing cache | [Configure Flexcard Settings](https://help.salesforce.com/s/articleView?id=xcloud.os_set_up_a_flexcard_in_the_flexcard_designer_37646.htm&language=en_US&type=5) |
| Old versions keep loading | Ask Salesforce Support to enable the Template API setting | [Configure Flexcard Settings](https://help.salesforce.com/s/articleView?id=xcloud.os_set_up_a_flexcard_in_the_flexcard_designer_37646.htm&language=en_US&type=5) |
| Parent data node | Child uses the parent's data; fields must exist in the parent's source | [Embed Flexcard in a Flexcard](https://help.salesforce.com/s/articleView?id=xcloud.os_embed_flexcard_inside_another_flexcard_29030.htm&language=en_US&type=5) |
| Custom CSS support | Salesforce Support can't assist with custom CSS issues | [Style a Flexcard](https://help.salesforce.com/s/articleView?id=xcloud.os_style_flexcard_elements_38751.htm&language=en_US&type=5) |
| Child Flexcards | Recommended at most 7 per parent | [Recommended Limits](https://help.salesforce.com/s/articleView?id=xcloud.os_omnistudio_design_assistant_recommended_limits.htm&language=en_US&type=5) |
| Data Table rows | Recommended at most 750 | [Recommended Limits](https://help.salesforce.com/s/articleView?id=xcloud.os_omnistudio_design_assistant_recommended_limits.htm&language=en_US&type=5) |

## Check yourself

- Why create a new version before opening an active card in the standard designer?
- When should you contact Salesforce Support about a Flexcard update?
- Why deselect Preload Conditional Component on a conditional element?
- What is the recommended maximum number of child Flexcards in a parent?

## Sources

- [Best Practices for Using the Omnistudio Standard Designer](https://help.salesforce.com/s/articleView?id=xcloud.os_best_practices_for_using_the_omnistudio_standard_designer.htm&language=en_US&type=5)
- [Configure Flexcard Settings](https://help.salesforce.com/s/articleView?id=xcloud.os_set_up_a_flexcard_in_the_flexcard_designer_37646.htm&language=en_US&type=5)
- [Embed Flexcard in a Flexcard](https://help.salesforce.com/s/articleView?id=xcloud.os_embed_flexcard_inside_another_flexcard_29030.htm&language=en_US&type=5)
- [Style a Flexcard](https://help.salesforce.com/s/articleView?id=xcloud.os_style_flexcard_elements_38751.htm&language=en_US&type=5)
- [Recommended Limits](https://help.salesforce.com/s/articleView?id=xcloud.os_omnistudio_design_assistant_recommended_limits.htm&language=en_US&type=5)
- [Omnistudio Flexcards](https://help.salesforce.com/s/articleView?id=sf.os_omnistudio_flexcards_24388.htm&language=en_US&type=5)
- [Set Up Conditions to a Flexcard Element](https://help.salesforce.com/s/articleView?id=sf.os_add_conditions_to_a_flexcard_element_35370.htm&language=en_US&type=5)
- [Disable Platform Cache for Flexcards in Omnistudio](https://help.salesforce.com/s/articleView?id=sf.os_disable_platform_cache_for_flexcards_in_omnistudio_38435.htm&language=en_US&type=5)
- [Monitor Flexcards and Omniscripts with Design Assistant (release note)](https://help.salesforce.com/s/articleView?id=release-notes.rn_omnistudio_validate_manage_health_flexcards_omniscripts.htm&release=254&language=en_US&type=5)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 4 linked practice questions, and unlimited timed mock exams are included with the Omnistudio Developer pack (USD $19): https://www.certifyforce.com/practice-exams