> For the complete documentation index, see [llms.txt](https://developer.kizen.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.kizen.com/docs/concepts/objects/custom-fields/custom-field-apis.md).

# Custom Field APIs

## Overview

<code class="expression">space.vars.field</code> APIs expose field metadata so developers can understand schemas, validate configurations, and build integrations that adapt as data models evolve. These endpoints support schema-aware development by enabling dynamic field references instead of static mappings.

Access to metadata is essential for scalable integration design because it allows applications to:

* Discover schema structure automatically
* Validate payloads before synchronization
* Adapt to configuration changes
* Map fields across systems
* Support middleware and transformation workflows

Using metadata-driven integrations reduces the risk of failures caused by schema drift and improves long-term maintainability.

### How Custom Fields Are Exposed Programmatically

<code class="expression">space.vars.fields</code> are exposed through metadata endpoints as structured objects that describe how each field behaves. API responses include field identifiers, data types, configuration and validation rules, permission-based visibility, and category groupings.

Use these APIs when integrations must adapt to changing schemas or validate configuration before writing data. Retrieving field metadata helps ensure valid values, supports field mapping, enables dynamic integrations, and reduces reliance on hard-coded references for greater long-term stability.

***

## API Topics in This Section

Use the following endpoints to retrieve and interact with <code class="expression">space.vars.field</code> metadata:

* [Retrieve Object Details API](/docs/concepts/objects/object-apis/retrieve-object-details-by-id-api.md)
* [Search for Object Fields API](/docs/concepts/objects/custom-fields/custom-field-apis/search-object-fields-api.md)
* [Retrieve Object Field Options API](/docs/concepts/objects/custom-fields/custom-field-apis/retrieve-object-field-options-api.md)

Use these endpoints to fetch metadata and available option sets, allowing you to discover the schema and verify valid values before sending data through your integration.

Dynamic tag fields also support runtime value creation. To reference available tags programmatically, retrieve field options using the field options endpoint before submitting data.

***

## What’s Next

Review related metadata and schema topics when designing integrations to ensure your implementation can adapt as the platform evolves. Continue building schema-aware integrations with the following resources:

<details>

<summary>Related Topics</summary>

* [Custom Fields](/docs/concepts/objects/custom-fields.md)
* [Search for Custom Object Fields API](/docs/concepts/objects/custom-fields/custom-field-apis/search-object-fields-api.md)
* [Retrieve Object Field Options API](/docs/concepts/objects/custom-fields/custom-field-apis/retrieve-object-field-options-api.md)
* [Retrieve Object Details API](/docs/concepts/objects/object-apis/retrieve-object-details-by-id-api.md)
* [Custom Field Permissions](/docs/concepts/objects/custom-fields/custom-field-permissions.md)

</details>


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