Developer Changelog

Legacy APIs and Apps: What's Going Unsupported and When

criley@hubspot.com (Chris Riley) — Tue, 15 Sep 2026 13:55:41 GMT

At Fall Spotlight on September 15, HubSpot is announcing the end of support for v1-v3 APIs, legacy public apps, and legacy private apps, all with a September 2027 enforcement date. If your integration or app uses any of these, you have a 12-month window to migrate.

This changelog covers v1-v3. Support for v4 is ending on its own separate timeline, March 30, 2027, which was announced earlier this year. See the previously published v4 changelog for that timeline.

This post covers breaking changes only. For everything new and non-breaking in this release, including the APIs reaching general availability, the updated APIs, the new public betas, and the latest AI builder tools, see the Fall Spotlight 2026 developer rollup.

Fall 2026 Spotlight - Developer / Builder Updates

Brooke Bond — Tue, 15 Sep 2026 13:55:01 GMT

This changelog rounds up the developer and builder updates in HubSpot's Fall Spotlight 2026 release: what's now generally available on Developer Platform version 2026.09, the new and updated APIs, the APIs entering public beta, and the latest AI builder tools. To learn more about what was announced during UNBOUND, visit the general Spotlight page and the developer Spotlight page.

This rollup covers non-breaking updates only. For the breaking changes in this release, including legacy API versions and legacy apps moving to unsupported status, see Breaking Change: Legacy APIs and Legacy Apps Are Going Unsupported.

August 2026 Rollup

aswebster@hubspot.com (Ashley Webster) — Thu, 27 Aug 2026 18:30:02 GMT

August’s developer updates expand how teams bring data into HubSpot and automate CRM operations. This month introduces webhook data sources for Data Studio, preserves active workflow enrollments when records are merged, and adds app object support to association workflow actions. Together, these changes reduce custom integration work and help automations continue with less manual intervention.

Legacy Private App Creation Being Disabled

dedson@hubspot.com (Dennis Edson) — Thu, 27 Aug 2026 13:42:19 GMT

HubSpot is permanently removing the ability to create new legacy, non-Project based, private apps through the account UI. Users needing similar functionality should use Service Keys, available via Developer Platform Projects version 2026.09 or later, which supports system-to-system integrations. This sunset impacts customer accounts on two timelines based on their age. All existing legacy private apps are not affected at this time.

Pipelines API V1 Sunset: December 4, 2026

dedson@hubspot.com (Dennis Edson) — Fri, 14 Aug 2026 14:37:13 GMT

HubSpot will sunset the Pipelines API V1 on December 4, 2026. After this date, the API will no longer be supported. If your integration relies on V1 endpoints, you'll need to migrate to the 2026-03 or newer version before the deadline to avoid disruption.

Node 18.x and 20.x Runtimes Deprecated for Chatflow Custom Code Snippets

dedson@hubspot.com (Dennis Edson) — Wed, 12 Aug 2026 20:04:13 GMT

Node 18.x and 20.x are being deprecated as supported runtimes for Chatflows custom code snippets. If you have bot code snippets running on either of these versions, you need to upgrade them to Node 24.x before August 31st, 2026, or you will lose the ability to edit those snippets until the upgrade is completed.

Breaking Change: CRM API Write Validation Enforcement Starting with the 2026-09 API Version

dedson@hubspot.com (Dennis Edson) — Tue, 11 Aug 2026 15:11:49 GMT

Starting with the /2026-09/ API version shipping on September 8, 2026, HubSpot will enforce admin-configured validation rules on all CRM API write paths. If your integration creates or updates CRM records, please make sure that it conforms to the below changes before updating your version of the API.

July 2026 Rollup

jmclaren@hubspot.com (Jon McLaren) — Fri, 31 Jul 2026 16:07:18 GMT

This month's updates include a raised owner property limit, larger Webhooks Journal batch sizes, and a new historical API usage chart — plus public betas for Contract Imports and the Payment Links API. Read on for the details.

Breaking Change: Pipeline and pipeline stage delete endpoints will validate references by default starting with the 2026-09 API version

dedson@hubspot.com (Dennis Edson) — Tue, 21 Jul 2026 16:00:17 GMT

7/23/2026 Edit - The post has been updated to include the Deal object specific validateDealStageUsagesBeforeDelete query parameter.

Availability: This is a breaking change for the next GA date-based API version, /2026-09/. It does not change the behavior of the current GA API version or earlier versions. Integrations will see this behavior only after moving to /2026-09/ or later.

Learn more about HubSpot's Date Based Versioning

What is changing?

Starting in version /2026-09/ of the Pipelines API, HubSpot will validate references before deleting a pipeline or pipeline stage. If the pipeline or stage is in use, the delete request will be blocked and return a validation error.

This makes public API deletes behave the same way as deletes from the pipeline settings page in HubSpot, where deleting a pipeline or stage is already blocked when it is in use.

The reference check is enabled by default because validateReferencesBeforeDelete and validateDealStageUsagesBeforeDelete will default to true in /2026-09/.

validateDealStageUsagesBeforeDelete is used for the Deal object and validateReferencesBeforeDelete for all other object types.

To bypass this validation, pass:

validateReferencesBeforeDelete=false

validateDealStageUsageBeforeDelete=false

Affected endpoints

DELETE/crm/pipelines/{version}/{objectType}/{pipelineId}
DELETE/crm/pipelines/{version}/{objectType}/{pipelineId}/stages/{stageId}
PATCH/crm/pipelines/[version]/({objectType})/({pipelineId})
PUT/crm/pipelines/[version]/({objectType})/({pipelineId})

This change applies when {version} is /2026-09/ or a later DBV version.

Why does this matter?

This change makes pipeline deletion behavior consistent between the HubSpot UI and the public API, and helps prevent accidental deletion of pipelines or stages that are still referenced by existing objects.

Integrations that currently rely on deleting in-use pipelines or stages may receive a 400 validation error after upgrading to /2026-09/. To preserve the previous behavior, explicitly set validateReferencesBeforeDelete=false, or validateDealStageUsagesBeforeDelete, or remain on an earlier version until you are ready to migrate.

Migration guidance

Before upgrading to /2026-09/, review any integration logic that deletes pipelines or pipeline stages. If your integration expects deletes to succeed even when a pipeline or stage is in use, update the request to pass false to the above mentioned query parameters. Otherwise, handle the new validation error and prompt users to remove references before retrying the delete.

Question or comments? Join us in the community

Developer updates for June 2026

dedson@hubspot.com (Dennis Edson) — Mon, 29 Jun 2026 18:44:29 GMT

June’s developer updates include new CRM and customer success signals, cleaner subscription-status histories, expanded Knowledge Vault support for structured data, app object activity association controls, quote module customization, and several CLI improvements. This roundup also covers custom event timeline configuration and new Remote MCP server capabilities for content analytics and landing page creation.