---
title: "Klaviyo Custom Objects beta APIs change shape at revision 2026-10-15.pre | Harbyn"
description: "Klaviyo Custom Objects beta APIs change shape at revision 2026-10-15.pre."
canonical: "https://harbyn.com/changes/klaviyo/2026-10-15-custom-objects-metadata-and-record-apis-change-shape-in-beta"
last-updated: 2026-10-15
---

# Klaviyo Custom Objects beta APIs change shape at revision 2026-10-15.pre

Markdown version of <https://harbyn.com/changes/klaviyo/2026-10-15-custom-objects-metadata-and-record-apis-change-shape-in-beta>.

Breaking change - Klaviyo. low severity. In effect.

At beta revision 2026-10-15.pre the Custom Objects metadata and record APIs (object types, object schemas, object records and data source mappings) change shape and remain in beta. The generally available versions at revision 2026-07-15 are not affected.

The deadline passed on Oct 15, 2026.

## Facts

| Fact | Value |
| --- | --- |
| Vendor | [Klaviyo](https://harbyn.com/vendors/klaviyo.md) |
| Kind | Breaking change |
| Severity | low |
| Status | In effect |
| Announced | Oct 15, 2026 |
| Effective | Oct 15, 2026 |
| Added to Harbyn | Oct 15, 2026 |
| Lead time | Added on the day of the deadline |
| API versions (revision) | `2026-10-15.pre` |
| Review | Reviewed by a person, extracted by a model |

## Find it in your code

```sh
npx harbyn scan
```

The scanner reads your repository on your machine and reports every file and line that uses the identifiers above. Nothing leaves your machine.

## Sources

Where this event comes from: the page we read, when we read it, and the hash of that snapshot.

- <https://developers.klaviyo.com/en/docs/changelog_> (changelog, fetched 2026-10-15 17:07 UTC, sha256 `01d139e2f77e3a1d11324ffe05cb17966313e973a91e9e42b712e44406fcb0b7`)

## Related changes

### More from Klaviyo

- [Revision 2026-10-15 replaces Campaigns API request and response shapes with the omnichannel model](https://harbyn.com/changes/klaviyo/2026-10-15-omnichannel-campaigns-api-changes-campaign-request-and-response-shapes.md) (Breaking change, effective Oct 15, 2026)
- [Revision 2026-10-15 changes the universal content display\_options shape](https://harbyn.com/changes/klaviyo/2026-10-15-universal-content-display-options-has-a-new-shape.md) (Breaking change, effective Oct 15, 2026)

### Changes at other vendors

- [Amazon Selling Partner API: October listing attribute usage and enumeration value updates](https://harbyn.com/changes/amazon-sp-api/2026-10-14-sp-api-updates-new-listings-items-api-ivp-values-in-eu5-jp-and-ca-stores-oct-2.md) (effective Oct 26, 2026)
- [Supabase: four CBC-mode TLS 1.2 cipher suites will be removed from project HTTP APIs](https://harbyn.com/changes/supabase/2026-10-12-an-outdated-subset-of-tls-1-2-ciphers-will-be-disabled-on-project-http-apis.md) (effective Nov 10, 2026)
- [Google Workspace APIs: OAuth clients must be marked as agentic to call Google Workspace MCP servers](https://harbyn.com/changes/google-workspace/2026-10-12-oauth-clients-must-be-marked-as-agentic-to-call-google-workspace-mcp-servers.md) (effective Nov 11, 2026)
- [Bitbucket Cloud API: Git Credential Manager upgrade required for OAuth 2.0 Git authentication](https://harbyn.com/changes/bitbucket/2026-10-13-git-credential-manager-upgrade-required-for-oauth-2-0-git-authentication.md) (effective Nov 30, 2026)

[All upcoming deadlines](https://harbyn.com/deadlines.md)