---
schema_version: "1"
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title: Writable External Objects Considerations for Salesforce Connect—Custom Adapters
collection: admin
version: current
locale: en-us
portal_url: https://docs.salesforce.com/admin/current/en-us/platform/264-0-0/apex_considerations_writable_external_objects.md
canonical_url: https://help.salesforce.com/s/articleView?id=platform.apex_considerations_writable_external_objects.htm&release=264.0.0&type=5
source_site: help.salesforce.com
content_type: documentation
content_hash: 9f48f6d932e10b10e93fe09e99bd8adb9bc69d7cab03782832f3b8e87c140c82
description: Some special behaviors and limitations affect writable external objects that are associated with custom adapters for Salesforce Connect.
products:
  - Salesforce Platform
  - Security
release: "264"
---
# Writable External Objects Considerations for Salesforce Connect—Custom Adapters

Some special behaviors and limitations affect writable external objects that are associated with custom adapters for Salesforce Connect.

### Required Editions

<table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small edition">
      <colgroup>
        <col>
      </colgroup>
      <tbody>
        <tr class="">
          <td class="slds-cell-wrap" style="vertical-align:top;">Available in: both Salesforce Classic and Lightning Experience (not for high-data-volume
            external objects)</td>

        </tr>
        <tr class="">
          <td class="slds-cell-wrap" style="vertical-align:top;">
            <p>Available in: <strong>Developer</strong> Edition</p>
            <p style="margin-bottom:0;">Available for an extra cost
              in: <strong>Enterprise</strong>, <strong>Performance</strong>, and <strong>Unlimited</strong>
              Editions</p>
          </td>

        </tr>
      </tbody>
    </table>

- Writable external objects aren’t available for high-data-volume external data sources.
- Queued changes to the external data execute over time, so external object records that are read successively can contain different data.

Also review the considerations that apply to all Salesforce Connect adapters.

#### See Also

- [Writable External Objects in Salesforce Connect](https://help.salesforce.com/s/articleView?id=platform.platform_connect_considerations_writable_external_objects.htm&release=264.0.0&type=5 "Select Writable External Objects when you define an external data source and use Salesforce Connect external objects to create, update, and delete data. External objects are read only by default.")
- [Custom Adapter for Salesforce Connect](https://help.salesforce.com/s/articleView?id=platform.apex_adapter_about.htm&release=264.0.0&type=5 "Connect to any data anywhere for a complete view of your business. Use the Apex Connector Framework to develop a custom adapter for Salesforce Connect.")
- [_Apex Developer Guide_ : Writable External Objects](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_connector_external_objects_writeable.htm)